mirror of
https://github.com/torvalds/linux.git
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4de13d7aa8
Pull block core updates from Jens Axboe: - Major bit is Kents prep work for immutable bio vecs. - Stable candidate fix for a scheduling-while-atomic in the queue bypass operation. - Fix for the hang on exceeded rq->datalen 32-bit unsigned when merging discard bios. - Tejuns changes to convert the writeback thread pool to the generic workqueue mechanism. - Runtime PM framework, SCSI patches exists on top of these in James' tree. - A few random fixes. * 'for-3.10/core' of git://git.kernel.dk/linux-block: (40 commits) relay: move remove_buf_file inside relay_close_buf partitions/efi.c: replace useless kzalloc's by kmalloc's fs/block_dev.c: fix iov_shorten() criteria in blkdev_aio_read() block: fix max discard sectors limit blkcg: fix "scheduling while atomic" in blk_queue_bypass_start Documentation: cfq-iosched: update documentation help for cfq tunables writeback: expose the bdi_wq workqueue writeback: replace custom worker pool implementation with unbound workqueue writeback: remove unused bdi_pending_list aoe: Fix unitialized var usage bio-integrity: Add explicit field for owner of bip_buf block: Add an explicit bio flag for bios that own their bvec block: Add bio_alloc_pages() block: Convert some code to bio_for_each_segment_all() block: Add bio_for_each_segment_all() bounce: Refactor __blk_queue_bounce to not use bi_io_vec raid1: use bio_copy_data() pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage pktcdvd: use bio_copy_data() block: Add bio_copy_data() ...
2020 lines
48 KiB
C
2020 lines
48 KiB
C
/*
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* Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public Licens
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
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*
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*/
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/uio.h>
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#include <linux/iocontext.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/mempool.h>
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#include <linux/workqueue.h>
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#include <linux/cgroup.h>
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#include <scsi/sg.h> /* for struct sg_iovec */
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#include <trace/events/block.h>
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/*
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* Test patch to inline a certain number of bi_io_vec's inside the bio
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* itself, to shrink a bio data allocation from two mempool calls to one
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*/
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#define BIO_INLINE_VECS 4
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static mempool_t *bio_split_pool __read_mostly;
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/*
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* if you change this list, also change bvec_alloc or things will
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* break badly! cannot be bigger than what you can fit into an
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* unsigned short
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*/
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#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
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static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
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BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
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};
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#undef BV
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/*
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* fs_bio_set is the bio_set containing bio and iovec memory pools used by
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* IO code that does not need private memory pools.
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*/
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struct bio_set *fs_bio_set;
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EXPORT_SYMBOL(fs_bio_set);
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/*
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* Our slab pool management
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*/
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struct bio_slab {
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struct kmem_cache *slab;
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unsigned int slab_ref;
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unsigned int slab_size;
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char name[8];
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};
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static DEFINE_MUTEX(bio_slab_lock);
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static struct bio_slab *bio_slabs;
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static unsigned int bio_slab_nr, bio_slab_max;
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static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
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{
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unsigned int sz = sizeof(struct bio) + extra_size;
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struct kmem_cache *slab = NULL;
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struct bio_slab *bslab, *new_bio_slabs;
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unsigned int new_bio_slab_max;
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unsigned int i, entry = -1;
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mutex_lock(&bio_slab_lock);
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i = 0;
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while (i < bio_slab_nr) {
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bslab = &bio_slabs[i];
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if (!bslab->slab && entry == -1)
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entry = i;
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else if (bslab->slab_size == sz) {
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slab = bslab->slab;
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bslab->slab_ref++;
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break;
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}
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i++;
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}
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if (slab)
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goto out_unlock;
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if (bio_slab_nr == bio_slab_max && entry == -1) {
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new_bio_slab_max = bio_slab_max << 1;
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new_bio_slabs = krealloc(bio_slabs,
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new_bio_slab_max * sizeof(struct bio_slab),
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GFP_KERNEL);
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if (!new_bio_slabs)
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goto out_unlock;
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bio_slab_max = new_bio_slab_max;
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bio_slabs = new_bio_slabs;
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}
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if (entry == -1)
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entry = bio_slab_nr++;
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bslab = &bio_slabs[entry];
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snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
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slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL);
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if (!slab)
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goto out_unlock;
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printk(KERN_INFO "bio: create slab <%s> at %d\n", bslab->name, entry);
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bslab->slab = slab;
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bslab->slab_ref = 1;
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bslab->slab_size = sz;
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out_unlock:
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mutex_unlock(&bio_slab_lock);
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return slab;
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}
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static void bio_put_slab(struct bio_set *bs)
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{
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struct bio_slab *bslab = NULL;
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unsigned int i;
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mutex_lock(&bio_slab_lock);
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for (i = 0; i < bio_slab_nr; i++) {
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if (bs->bio_slab == bio_slabs[i].slab) {
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bslab = &bio_slabs[i];
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break;
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}
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}
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if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
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goto out;
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WARN_ON(!bslab->slab_ref);
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if (--bslab->slab_ref)
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goto out;
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kmem_cache_destroy(bslab->slab);
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bslab->slab = NULL;
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out:
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mutex_unlock(&bio_slab_lock);
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}
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unsigned int bvec_nr_vecs(unsigned short idx)
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{
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return bvec_slabs[idx].nr_vecs;
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}
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void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
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{
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BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
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if (idx == BIOVEC_MAX_IDX)
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mempool_free(bv, pool);
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else {
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struct biovec_slab *bvs = bvec_slabs + idx;
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kmem_cache_free(bvs->slab, bv);
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}
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}
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struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
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mempool_t *pool)
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{
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struct bio_vec *bvl;
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/*
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* see comment near bvec_array define!
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*/
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switch (nr) {
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case 1:
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*idx = 0;
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break;
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case 2 ... 4:
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*idx = 1;
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break;
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case 5 ... 16:
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*idx = 2;
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break;
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case 17 ... 64:
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*idx = 3;
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break;
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case 65 ... 128:
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*idx = 4;
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break;
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case 129 ... BIO_MAX_PAGES:
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*idx = 5;
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break;
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default:
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return NULL;
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}
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/*
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* idx now points to the pool we want to allocate from. only the
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* 1-vec entry pool is mempool backed.
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*/
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if (*idx == BIOVEC_MAX_IDX) {
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fallback:
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bvl = mempool_alloc(pool, gfp_mask);
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} else {
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struct biovec_slab *bvs = bvec_slabs + *idx;
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gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
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/*
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* Make this allocation restricted and don't dump info on
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* allocation failures, since we'll fallback to the mempool
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* in case of failure.
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*/
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__gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
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/*
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* Try a slab allocation. If this fails and __GFP_WAIT
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* is set, retry with the 1-entry mempool
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*/
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bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
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if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
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*idx = BIOVEC_MAX_IDX;
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goto fallback;
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}
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}
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return bvl;
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}
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static void __bio_free(struct bio *bio)
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{
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bio_disassociate_task(bio);
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if (bio_integrity(bio))
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bio_integrity_free(bio);
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}
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static void bio_free(struct bio *bio)
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{
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struct bio_set *bs = bio->bi_pool;
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void *p;
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__bio_free(bio);
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if (bs) {
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if (bio_flagged(bio, BIO_OWNS_VEC))
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bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
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/*
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* If we have front padding, adjust the bio pointer before freeing
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*/
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p = bio;
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p -= bs->front_pad;
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mempool_free(p, bs->bio_pool);
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} else {
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/* Bio was allocated by bio_kmalloc() */
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kfree(bio);
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}
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}
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void bio_init(struct bio *bio)
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{
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memset(bio, 0, sizeof(*bio));
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bio->bi_flags = 1 << BIO_UPTODATE;
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atomic_set(&bio->bi_cnt, 1);
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}
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EXPORT_SYMBOL(bio_init);
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/**
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* bio_reset - reinitialize a bio
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* @bio: bio to reset
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*
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* Description:
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* After calling bio_reset(), @bio will be in the same state as a freshly
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* allocated bio returned bio bio_alloc_bioset() - the only fields that are
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* preserved are the ones that are initialized by bio_alloc_bioset(). See
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* comment in struct bio.
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*/
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void bio_reset(struct bio *bio)
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{
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unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
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__bio_free(bio);
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memset(bio, 0, BIO_RESET_BYTES);
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bio->bi_flags = flags|(1 << BIO_UPTODATE);
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}
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EXPORT_SYMBOL(bio_reset);
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static void bio_alloc_rescue(struct work_struct *work)
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{
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struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
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struct bio *bio;
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while (1) {
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spin_lock(&bs->rescue_lock);
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bio = bio_list_pop(&bs->rescue_list);
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spin_unlock(&bs->rescue_lock);
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if (!bio)
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break;
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generic_make_request(bio);
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}
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}
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static void punt_bios_to_rescuer(struct bio_set *bs)
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{
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struct bio_list punt, nopunt;
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struct bio *bio;
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/*
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* In order to guarantee forward progress we must punt only bios that
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* were allocated from this bio_set; otherwise, if there was a bio on
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* there for a stacking driver higher up in the stack, processing it
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* could require allocating bios from this bio_set, and doing that from
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* our own rescuer would be bad.
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*
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* Since bio lists are singly linked, pop them all instead of trying to
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* remove from the middle of the list:
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*/
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bio_list_init(&punt);
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bio_list_init(&nopunt);
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while ((bio = bio_list_pop(current->bio_list)))
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bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
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*current->bio_list = nopunt;
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spin_lock(&bs->rescue_lock);
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bio_list_merge(&bs->rescue_list, &punt);
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spin_unlock(&bs->rescue_lock);
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queue_work(bs->rescue_workqueue, &bs->rescue_work);
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}
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/**
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* bio_alloc_bioset - allocate a bio for I/O
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* @gfp_mask: the GFP_ mask given to the slab allocator
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* @nr_iovecs: number of iovecs to pre-allocate
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* @bs: the bio_set to allocate from.
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*
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* Description:
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* If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
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* backed by the @bs's mempool.
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*
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* When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
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* able to allocate a bio. This is due to the mempool guarantees. To make this
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* work, callers must never allocate more than 1 bio at a time from this pool.
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* Callers that need to allocate more than 1 bio must always submit the
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* previously allocated bio for IO before attempting to allocate a new one.
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* Failure to do so can cause deadlocks under memory pressure.
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*
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* Note that when running under generic_make_request() (i.e. any block
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* driver), bios are not submitted until after you return - see the code in
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* generic_make_request() that converts recursion into iteration, to prevent
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* stack overflows.
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*
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* This would normally mean allocating multiple bios under
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* generic_make_request() would be susceptible to deadlocks, but we have
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* deadlock avoidance code that resubmits any blocked bios from a rescuer
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* thread.
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*
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* However, we do not guarantee forward progress for allocations from other
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* mempools. Doing multiple allocations from the same mempool under
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* generic_make_request() should be avoided - instead, use bio_set's front_pad
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* for per bio allocations.
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*
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* RETURNS:
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* Pointer to new bio on success, NULL on failure.
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*/
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struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
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{
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gfp_t saved_gfp = gfp_mask;
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unsigned front_pad;
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unsigned inline_vecs;
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unsigned long idx = BIO_POOL_NONE;
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struct bio_vec *bvl = NULL;
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struct bio *bio;
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void *p;
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if (!bs) {
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if (nr_iovecs > UIO_MAXIOV)
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return NULL;
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p = kmalloc(sizeof(struct bio) +
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nr_iovecs * sizeof(struct bio_vec),
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gfp_mask);
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front_pad = 0;
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inline_vecs = nr_iovecs;
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} else {
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/*
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* generic_make_request() converts recursion to iteration; this
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* means if we're running beneath it, any bios we allocate and
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* submit will not be submitted (and thus freed) until after we
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* return.
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*
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* This exposes us to a potential deadlock if we allocate
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* multiple bios from the same bio_set() while running
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* underneath generic_make_request(). If we were to allocate
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* multiple bios (say a stacking block driver that was splitting
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* bios), we would deadlock if we exhausted the mempool's
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* reserve.
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*
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* We solve this, and guarantee forward progress, with a rescuer
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* workqueue per bio_set. If we go to allocate and there are
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* bios on current->bio_list, we first try the allocation
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* without __GFP_WAIT; if that fails, we punt those bios we
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* would be blocking to the rescuer workqueue before we retry
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* with the original gfp_flags.
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*/
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if (current->bio_list && !bio_list_empty(current->bio_list))
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gfp_mask &= ~__GFP_WAIT;
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p = mempool_alloc(bs->bio_pool, gfp_mask);
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if (!p && gfp_mask != saved_gfp) {
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punt_bios_to_rescuer(bs);
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gfp_mask = saved_gfp;
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p = mempool_alloc(bs->bio_pool, gfp_mask);
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}
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front_pad = bs->front_pad;
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inline_vecs = BIO_INLINE_VECS;
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}
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if (unlikely(!p))
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return NULL;
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bio = p + front_pad;
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bio_init(bio);
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if (nr_iovecs > inline_vecs) {
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bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
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if (!bvl && gfp_mask != saved_gfp) {
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punt_bios_to_rescuer(bs);
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gfp_mask = saved_gfp;
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bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
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}
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if (unlikely(!bvl))
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goto err_free;
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bio->bi_flags |= 1 << BIO_OWNS_VEC;
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} else if (nr_iovecs) {
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bvl = bio->bi_inline_vecs;
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}
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bio->bi_pool = bs;
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bio->bi_flags |= idx << BIO_POOL_OFFSET;
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bio->bi_max_vecs = nr_iovecs;
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bio->bi_io_vec = bvl;
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return bio;
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err_free:
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mempool_free(p, bs->bio_pool);
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return NULL;
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}
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EXPORT_SYMBOL(bio_alloc_bioset);
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|
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void zero_fill_bio(struct bio *bio)
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{
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unsigned long flags;
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struct bio_vec *bv;
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int i;
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bio_for_each_segment(bv, bio, i) {
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char *data = bvec_kmap_irq(bv, &flags);
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memset(data, 0, bv->bv_len);
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flush_dcache_page(bv->bv_page);
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bvec_kunmap_irq(data, &flags);
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}
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}
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EXPORT_SYMBOL(zero_fill_bio);
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/**
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* bio_put - release a reference to a bio
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* @bio: bio to release reference to
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*
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* Description:
|
|
* Put a reference to a &struct bio, either one you have gotten with
|
|
* bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
|
|
**/
|
|
void bio_put(struct bio *bio)
|
|
{
|
|
BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
|
|
|
|
/*
|
|
* last put frees it
|
|
*/
|
|
if (atomic_dec_and_test(&bio->bi_cnt))
|
|
bio_free(bio);
|
|
}
|
|
EXPORT_SYMBOL(bio_put);
|
|
|
|
inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
|
|
{
|
|
if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
|
|
blk_recount_segments(q, bio);
|
|
|
|
return bio->bi_phys_segments;
|
|
}
|
|
EXPORT_SYMBOL(bio_phys_segments);
|
|
|
|
/**
|
|
* __bio_clone - clone a bio
|
|
* @bio: destination bio
|
|
* @bio_src: bio to clone
|
|
*
|
|
* Clone a &bio. Caller will own the returned bio, but not
|
|
* the actual data it points to. Reference count of returned
|
|
* bio will be one.
|
|
*/
|
|
void __bio_clone(struct bio *bio, struct bio *bio_src)
|
|
{
|
|
memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
|
|
bio_src->bi_max_vecs * sizeof(struct bio_vec));
|
|
|
|
/*
|
|
* most users will be overriding ->bi_bdev with a new target,
|
|
* so we don't set nor calculate new physical/hw segment counts here
|
|
*/
|
|
bio->bi_sector = bio_src->bi_sector;
|
|
bio->bi_bdev = bio_src->bi_bdev;
|
|
bio->bi_flags |= 1 << BIO_CLONED;
|
|
bio->bi_rw = bio_src->bi_rw;
|
|
bio->bi_vcnt = bio_src->bi_vcnt;
|
|
bio->bi_size = bio_src->bi_size;
|
|
bio->bi_idx = bio_src->bi_idx;
|
|
}
|
|
EXPORT_SYMBOL(__bio_clone);
|
|
|
|
/**
|
|
* bio_clone_bioset - clone a bio
|
|
* @bio: bio to clone
|
|
* @gfp_mask: allocation priority
|
|
* @bs: bio_set to allocate from
|
|
*
|
|
* Like __bio_clone, only also allocates the returned bio
|
|
*/
|
|
struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
|
|
struct bio_set *bs)
|
|
{
|
|
struct bio *b;
|
|
|
|
b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
|
|
if (!b)
|
|
return NULL;
|
|
|
|
__bio_clone(b, bio);
|
|
|
|
if (bio_integrity(bio)) {
|
|
int ret;
|
|
|
|
ret = bio_integrity_clone(b, bio, gfp_mask);
|
|
|
|
if (ret < 0) {
|
|
bio_put(b);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
return b;
|
|
}
|
|
EXPORT_SYMBOL(bio_clone_bioset);
|
|
|
|
/**
|
|
* bio_get_nr_vecs - return approx number of vecs
|
|
* @bdev: I/O target
|
|
*
|
|
* Return the approximate number of pages we can send to this target.
|
|
* There's no guarantee that you will be able to fit this number of pages
|
|
* into a bio, it does not account for dynamic restrictions that vary
|
|
* on offset.
|
|
*/
|
|
int bio_get_nr_vecs(struct block_device *bdev)
|
|
{
|
|
struct request_queue *q = bdev_get_queue(bdev);
|
|
int nr_pages;
|
|
|
|
nr_pages = min_t(unsigned,
|
|
queue_max_segments(q),
|
|
queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
|
|
|
|
return min_t(unsigned, nr_pages, BIO_MAX_PAGES);
|
|
|
|
}
|
|
EXPORT_SYMBOL(bio_get_nr_vecs);
|
|
|
|
static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
|
|
*page, unsigned int len, unsigned int offset,
|
|
unsigned short max_sectors)
|
|
{
|
|
int retried_segments = 0;
|
|
struct bio_vec *bvec;
|
|
|
|
/*
|
|
* cloned bio must not modify vec list
|
|
*/
|
|
if (unlikely(bio_flagged(bio, BIO_CLONED)))
|
|
return 0;
|
|
|
|
if (((bio->bi_size + len) >> 9) > max_sectors)
|
|
return 0;
|
|
|
|
/*
|
|
* For filesystems with a blocksize smaller than the pagesize
|
|
* we will often be called with the same page as last time and
|
|
* a consecutive offset. Optimize this special case.
|
|
*/
|
|
if (bio->bi_vcnt > 0) {
|
|
struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
|
|
|
|
if (page == prev->bv_page &&
|
|
offset == prev->bv_offset + prev->bv_len) {
|
|
unsigned int prev_bv_len = prev->bv_len;
|
|
prev->bv_len += len;
|
|
|
|
if (q->merge_bvec_fn) {
|
|
struct bvec_merge_data bvm = {
|
|
/* prev_bvec is already charged in
|
|
bi_size, discharge it in order to
|
|
simulate merging updated prev_bvec
|
|
as new bvec. */
|
|
.bi_bdev = bio->bi_bdev,
|
|
.bi_sector = bio->bi_sector,
|
|
.bi_size = bio->bi_size - prev_bv_len,
|
|
.bi_rw = bio->bi_rw,
|
|
};
|
|
|
|
if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
|
|
prev->bv_len -= len;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
if (bio->bi_vcnt >= bio->bi_max_vecs)
|
|
return 0;
|
|
|
|
/*
|
|
* we might lose a segment or two here, but rather that than
|
|
* make this too complex.
|
|
*/
|
|
|
|
while (bio->bi_phys_segments >= queue_max_segments(q)) {
|
|
|
|
if (retried_segments)
|
|
return 0;
|
|
|
|
retried_segments = 1;
|
|
blk_recount_segments(q, bio);
|
|
}
|
|
|
|
/*
|
|
* setup the new entry, we might clear it again later if we
|
|
* cannot add the page
|
|
*/
|
|
bvec = &bio->bi_io_vec[bio->bi_vcnt];
|
|
bvec->bv_page = page;
|
|
bvec->bv_len = len;
|
|
bvec->bv_offset = offset;
|
|
|
|
/*
|
|
* if queue has other restrictions (eg varying max sector size
|
|
* depending on offset), it can specify a merge_bvec_fn in the
|
|
* queue to get further control
|
|
*/
|
|
if (q->merge_bvec_fn) {
|
|
struct bvec_merge_data bvm = {
|
|
.bi_bdev = bio->bi_bdev,
|
|
.bi_sector = bio->bi_sector,
|
|
.bi_size = bio->bi_size,
|
|
.bi_rw = bio->bi_rw,
|
|
};
|
|
|
|
/*
|
|
* merge_bvec_fn() returns number of bytes it can accept
|
|
* at this offset
|
|
*/
|
|
if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
|
|
bvec->bv_page = NULL;
|
|
bvec->bv_len = 0;
|
|
bvec->bv_offset = 0;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* If we may be able to merge these biovecs, force a recount */
|
|
if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
|
|
bio->bi_flags &= ~(1 << BIO_SEG_VALID);
|
|
|
|
bio->bi_vcnt++;
|
|
bio->bi_phys_segments++;
|
|
done:
|
|
bio->bi_size += len;
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* bio_add_pc_page - attempt to add page to bio
|
|
* @q: the target queue
|
|
* @bio: destination bio
|
|
* @page: page to add
|
|
* @len: vec entry length
|
|
* @offset: vec entry offset
|
|
*
|
|
* Attempt to add a page to the bio_vec maplist. This can fail for a
|
|
* number of reasons, such as the bio being full or target block device
|
|
* limitations. The target block device must allow bio's up to PAGE_SIZE,
|
|
* so it is always possible to add a single page to an empty bio.
|
|
*
|
|
* This should only be used by REQ_PC bios.
|
|
*/
|
|
int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
|
|
unsigned int len, unsigned int offset)
|
|
{
|
|
return __bio_add_page(q, bio, page, len, offset,
|
|
queue_max_hw_sectors(q));
|
|
}
|
|
EXPORT_SYMBOL(bio_add_pc_page);
|
|
|
|
/**
|
|
* bio_add_page - attempt to add page to bio
|
|
* @bio: destination bio
|
|
* @page: page to add
|
|
* @len: vec entry length
|
|
* @offset: vec entry offset
|
|
*
|
|
* Attempt to add a page to the bio_vec maplist. This can fail for a
|
|
* number of reasons, such as the bio being full or target block device
|
|
* limitations. The target block device must allow bio's up to PAGE_SIZE,
|
|
* so it is always possible to add a single page to an empty bio.
|
|
*/
|
|
int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
|
|
unsigned int offset)
|
|
{
|
|
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
|
|
return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
|
|
}
|
|
EXPORT_SYMBOL(bio_add_page);
|
|
|
|
struct submit_bio_ret {
|
|
struct completion event;
|
|
int error;
|
|
};
|
|
|
|
static void submit_bio_wait_endio(struct bio *bio, int error)
|
|
{
|
|
struct submit_bio_ret *ret = bio->bi_private;
|
|
|
|
ret->error = error;
|
|
complete(&ret->event);
|
|
}
|
|
|
|
/**
|
|
* submit_bio_wait - submit a bio, and wait until it completes
|
|
* @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
|
|
* @bio: The &struct bio which describes the I/O
|
|
*
|
|
* Simple wrapper around submit_bio(). Returns 0 on success, or the error from
|
|
* bio_endio() on failure.
|
|
*/
|
|
int submit_bio_wait(int rw, struct bio *bio)
|
|
{
|
|
struct submit_bio_ret ret;
|
|
|
|
rw |= REQ_SYNC;
|
|
init_completion(&ret.event);
|
|
bio->bi_private = &ret;
|
|
bio->bi_end_io = submit_bio_wait_endio;
|
|
submit_bio(rw, bio);
|
|
wait_for_completion(&ret.event);
|
|
|
|
return ret.error;
|
|
}
|
|
EXPORT_SYMBOL(submit_bio_wait);
|
|
|
|
/**
|
|
* bio_advance - increment/complete a bio by some number of bytes
|
|
* @bio: bio to advance
|
|
* @bytes: number of bytes to complete
|
|
*
|
|
* This updates bi_sector, bi_size and bi_idx; if the number of bytes to
|
|
* complete doesn't align with a bvec boundary, then bv_len and bv_offset will
|
|
* be updated on the last bvec as well.
|
|
*
|
|
* @bio will then represent the remaining, uncompleted portion of the io.
|
|
*/
|
|
void bio_advance(struct bio *bio, unsigned bytes)
|
|
{
|
|
if (bio_integrity(bio))
|
|
bio_integrity_advance(bio, bytes);
|
|
|
|
bio->bi_sector += bytes >> 9;
|
|
bio->bi_size -= bytes;
|
|
|
|
if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
|
|
return;
|
|
|
|
while (bytes) {
|
|
if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
|
|
WARN_ONCE(1, "bio idx %d >= vcnt %d\n",
|
|
bio->bi_idx, bio->bi_vcnt);
|
|
break;
|
|
}
|
|
|
|
if (bytes >= bio_iovec(bio)->bv_len) {
|
|
bytes -= bio_iovec(bio)->bv_len;
|
|
bio->bi_idx++;
|
|
} else {
|
|
bio_iovec(bio)->bv_len -= bytes;
|
|
bio_iovec(bio)->bv_offset += bytes;
|
|
bytes = 0;
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bio_advance);
|
|
|
|
/**
|
|
* bio_alloc_pages - allocates a single page for each bvec in a bio
|
|
* @bio: bio to allocate pages for
|
|
* @gfp_mask: flags for allocation
|
|
*
|
|
* Allocates pages up to @bio->bi_vcnt.
|
|
*
|
|
* Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
|
|
* freed.
|
|
*/
|
|
int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
|
|
{
|
|
int i;
|
|
struct bio_vec *bv;
|
|
|
|
bio_for_each_segment_all(bv, bio, i) {
|
|
bv->bv_page = alloc_page(gfp_mask);
|
|
if (!bv->bv_page) {
|
|
while (--bv >= bio->bi_io_vec)
|
|
__free_page(bv->bv_page);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(bio_alloc_pages);
|
|
|
|
/**
|
|
* bio_copy_data - copy contents of data buffers from one chain of bios to
|
|
* another
|
|
* @src: source bio list
|
|
* @dst: destination bio list
|
|
*
|
|
* If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
|
|
* @src and @dst as linked lists of bios.
|
|
*
|
|
* Stops when it reaches the end of either @src or @dst - that is, copies
|
|
* min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
|
|
*/
|
|
void bio_copy_data(struct bio *dst, struct bio *src)
|
|
{
|
|
struct bio_vec *src_bv, *dst_bv;
|
|
unsigned src_offset, dst_offset, bytes;
|
|
void *src_p, *dst_p;
|
|
|
|
src_bv = bio_iovec(src);
|
|
dst_bv = bio_iovec(dst);
|
|
|
|
src_offset = src_bv->bv_offset;
|
|
dst_offset = dst_bv->bv_offset;
|
|
|
|
while (1) {
|
|
if (src_offset == src_bv->bv_offset + src_bv->bv_len) {
|
|
src_bv++;
|
|
if (src_bv == bio_iovec_idx(src, src->bi_vcnt)) {
|
|
src = src->bi_next;
|
|
if (!src)
|
|
break;
|
|
|
|
src_bv = bio_iovec(src);
|
|
}
|
|
|
|
src_offset = src_bv->bv_offset;
|
|
}
|
|
|
|
if (dst_offset == dst_bv->bv_offset + dst_bv->bv_len) {
|
|
dst_bv++;
|
|
if (dst_bv == bio_iovec_idx(dst, dst->bi_vcnt)) {
|
|
dst = dst->bi_next;
|
|
if (!dst)
|
|
break;
|
|
|
|
dst_bv = bio_iovec(dst);
|
|
}
|
|
|
|
dst_offset = dst_bv->bv_offset;
|
|
}
|
|
|
|
bytes = min(dst_bv->bv_offset + dst_bv->bv_len - dst_offset,
|
|
src_bv->bv_offset + src_bv->bv_len - src_offset);
|
|
|
|
src_p = kmap_atomic(src_bv->bv_page);
|
|
dst_p = kmap_atomic(dst_bv->bv_page);
|
|
|
|
memcpy(dst_p + dst_bv->bv_offset,
|
|
src_p + src_bv->bv_offset,
|
|
bytes);
|
|
|
|
kunmap_atomic(dst_p);
|
|
kunmap_atomic(src_p);
|
|
|
|
src_offset += bytes;
|
|
dst_offset += bytes;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bio_copy_data);
|
|
|
|
struct bio_map_data {
|
|
struct bio_vec *iovecs;
|
|
struct sg_iovec *sgvecs;
|
|
int nr_sgvecs;
|
|
int is_our_pages;
|
|
};
|
|
|
|
static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
|
|
struct sg_iovec *iov, int iov_count,
|
|
int is_our_pages)
|
|
{
|
|
memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
|
|
memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
|
|
bmd->nr_sgvecs = iov_count;
|
|
bmd->is_our_pages = is_our_pages;
|
|
bio->bi_private = bmd;
|
|
}
|
|
|
|
static void bio_free_map_data(struct bio_map_data *bmd)
|
|
{
|
|
kfree(bmd->iovecs);
|
|
kfree(bmd->sgvecs);
|
|
kfree(bmd);
|
|
}
|
|
|
|
static struct bio_map_data *bio_alloc_map_data(int nr_segs,
|
|
unsigned int iov_count,
|
|
gfp_t gfp_mask)
|
|
{
|
|
struct bio_map_data *bmd;
|
|
|
|
if (iov_count > UIO_MAXIOV)
|
|
return NULL;
|
|
|
|
bmd = kmalloc(sizeof(*bmd), gfp_mask);
|
|
if (!bmd)
|
|
return NULL;
|
|
|
|
bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
|
|
if (!bmd->iovecs) {
|
|
kfree(bmd);
|
|
return NULL;
|
|
}
|
|
|
|
bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
|
|
if (bmd->sgvecs)
|
|
return bmd;
|
|
|
|
kfree(bmd->iovecs);
|
|
kfree(bmd);
|
|
return NULL;
|
|
}
|
|
|
|
static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
|
|
struct sg_iovec *iov, int iov_count,
|
|
int to_user, int from_user, int do_free_page)
|
|
{
|
|
int ret = 0, i;
|
|
struct bio_vec *bvec;
|
|
int iov_idx = 0;
|
|
unsigned int iov_off = 0;
|
|
|
|
bio_for_each_segment_all(bvec, bio, i) {
|
|
char *bv_addr = page_address(bvec->bv_page);
|
|
unsigned int bv_len = iovecs[i].bv_len;
|
|
|
|
while (bv_len && iov_idx < iov_count) {
|
|
unsigned int bytes;
|
|
char __user *iov_addr;
|
|
|
|
bytes = min_t(unsigned int,
|
|
iov[iov_idx].iov_len - iov_off, bv_len);
|
|
iov_addr = iov[iov_idx].iov_base + iov_off;
|
|
|
|
if (!ret) {
|
|
if (to_user)
|
|
ret = copy_to_user(iov_addr, bv_addr,
|
|
bytes);
|
|
|
|
if (from_user)
|
|
ret = copy_from_user(bv_addr, iov_addr,
|
|
bytes);
|
|
|
|
if (ret)
|
|
ret = -EFAULT;
|
|
}
|
|
|
|
bv_len -= bytes;
|
|
bv_addr += bytes;
|
|
iov_addr += bytes;
|
|
iov_off += bytes;
|
|
|
|
if (iov[iov_idx].iov_len == iov_off) {
|
|
iov_idx++;
|
|
iov_off = 0;
|
|
}
|
|
}
|
|
|
|
if (do_free_page)
|
|
__free_page(bvec->bv_page);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* bio_uncopy_user - finish previously mapped bio
|
|
* @bio: bio being terminated
|
|
*
|
|
* Free pages allocated from bio_copy_user() and write back data
|
|
* to user space in case of a read.
|
|
*/
|
|
int bio_uncopy_user(struct bio *bio)
|
|
{
|
|
struct bio_map_data *bmd = bio->bi_private;
|
|
int ret = 0;
|
|
|
|
if (!bio_flagged(bio, BIO_NULL_MAPPED))
|
|
ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
|
|
bmd->nr_sgvecs, bio_data_dir(bio) == READ,
|
|
0, bmd->is_our_pages);
|
|
bio_free_map_data(bmd);
|
|
bio_put(bio);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(bio_uncopy_user);
|
|
|
|
/**
|
|
* bio_copy_user_iov - copy user data to bio
|
|
* @q: destination block queue
|
|
* @map_data: pointer to the rq_map_data holding pages (if necessary)
|
|
* @iov: the iovec.
|
|
* @iov_count: number of elements in the iovec
|
|
* @write_to_vm: bool indicating writing to pages or not
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* Prepares and returns a bio for indirect user io, bouncing data
|
|
* to/from kernel pages as necessary. Must be paired with
|
|
* call bio_uncopy_user() on io completion.
|
|
*/
|
|
struct bio *bio_copy_user_iov(struct request_queue *q,
|
|
struct rq_map_data *map_data,
|
|
struct sg_iovec *iov, int iov_count,
|
|
int write_to_vm, gfp_t gfp_mask)
|
|
{
|
|
struct bio_map_data *bmd;
|
|
struct bio_vec *bvec;
|
|
struct page *page;
|
|
struct bio *bio;
|
|
int i, ret;
|
|
int nr_pages = 0;
|
|
unsigned int len = 0;
|
|
unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
|
|
|
|
for (i = 0; i < iov_count; i++) {
|
|
unsigned long uaddr;
|
|
unsigned long end;
|
|
unsigned long start;
|
|
|
|
uaddr = (unsigned long)iov[i].iov_base;
|
|
end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
start = uaddr >> PAGE_SHIFT;
|
|
|
|
/*
|
|
* Overflow, abort
|
|
*/
|
|
if (end < start)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
nr_pages += end - start;
|
|
len += iov[i].iov_len;
|
|
}
|
|
|
|
if (offset)
|
|
nr_pages++;
|
|
|
|
bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
|
|
if (!bmd)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ret = -ENOMEM;
|
|
bio = bio_kmalloc(gfp_mask, nr_pages);
|
|
if (!bio)
|
|
goto out_bmd;
|
|
|
|
if (!write_to_vm)
|
|
bio->bi_rw |= REQ_WRITE;
|
|
|
|
ret = 0;
|
|
|
|
if (map_data) {
|
|
nr_pages = 1 << map_data->page_order;
|
|
i = map_data->offset / PAGE_SIZE;
|
|
}
|
|
while (len) {
|
|
unsigned int bytes = PAGE_SIZE;
|
|
|
|
bytes -= offset;
|
|
|
|
if (bytes > len)
|
|
bytes = len;
|
|
|
|
if (map_data) {
|
|
if (i == map_data->nr_entries * nr_pages) {
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
|
|
page = map_data->pages[i / nr_pages];
|
|
page += (i % nr_pages);
|
|
|
|
i++;
|
|
} else {
|
|
page = alloc_page(q->bounce_gfp | gfp_mask);
|
|
if (!page) {
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
|
|
break;
|
|
|
|
len -= bytes;
|
|
offset = 0;
|
|
}
|
|
|
|
if (ret)
|
|
goto cleanup;
|
|
|
|
/*
|
|
* success
|
|
*/
|
|
if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
|
|
(map_data && map_data->from_user)) {
|
|
ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0);
|
|
if (ret)
|
|
goto cleanup;
|
|
}
|
|
|
|
bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
|
|
return bio;
|
|
cleanup:
|
|
if (!map_data)
|
|
bio_for_each_segment_all(bvec, bio, i)
|
|
__free_page(bvec->bv_page);
|
|
|
|
bio_put(bio);
|
|
out_bmd:
|
|
bio_free_map_data(bmd);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
/**
|
|
* bio_copy_user - copy user data to bio
|
|
* @q: destination block queue
|
|
* @map_data: pointer to the rq_map_data holding pages (if necessary)
|
|
* @uaddr: start of user address
|
|
* @len: length in bytes
|
|
* @write_to_vm: bool indicating writing to pages or not
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* Prepares and returns a bio for indirect user io, bouncing data
|
|
* to/from kernel pages as necessary. Must be paired with
|
|
* call bio_uncopy_user() on io completion.
|
|
*/
|
|
struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
|
|
unsigned long uaddr, unsigned int len,
|
|
int write_to_vm, gfp_t gfp_mask)
|
|
{
|
|
struct sg_iovec iov;
|
|
|
|
iov.iov_base = (void __user *)uaddr;
|
|
iov.iov_len = len;
|
|
|
|
return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
|
|
}
|
|
EXPORT_SYMBOL(bio_copy_user);
|
|
|
|
static struct bio *__bio_map_user_iov(struct request_queue *q,
|
|
struct block_device *bdev,
|
|
struct sg_iovec *iov, int iov_count,
|
|
int write_to_vm, gfp_t gfp_mask)
|
|
{
|
|
int i, j;
|
|
int nr_pages = 0;
|
|
struct page **pages;
|
|
struct bio *bio;
|
|
int cur_page = 0;
|
|
int ret, offset;
|
|
|
|
for (i = 0; i < iov_count; i++) {
|
|
unsigned long uaddr = (unsigned long)iov[i].iov_base;
|
|
unsigned long len = iov[i].iov_len;
|
|
unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
unsigned long start = uaddr >> PAGE_SHIFT;
|
|
|
|
/*
|
|
* Overflow, abort
|
|
*/
|
|
if (end < start)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
nr_pages += end - start;
|
|
/*
|
|
* buffer must be aligned to at least hardsector size for now
|
|
*/
|
|
if (uaddr & queue_dma_alignment(q))
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (!nr_pages)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
bio = bio_kmalloc(gfp_mask, nr_pages);
|
|
if (!bio)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ret = -ENOMEM;
|
|
pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
|
|
if (!pages)
|
|
goto out;
|
|
|
|
for (i = 0; i < iov_count; i++) {
|
|
unsigned long uaddr = (unsigned long)iov[i].iov_base;
|
|
unsigned long len = iov[i].iov_len;
|
|
unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
unsigned long start = uaddr >> PAGE_SHIFT;
|
|
const int local_nr_pages = end - start;
|
|
const int page_limit = cur_page + local_nr_pages;
|
|
|
|
ret = get_user_pages_fast(uaddr, local_nr_pages,
|
|
write_to_vm, &pages[cur_page]);
|
|
if (ret < local_nr_pages) {
|
|
ret = -EFAULT;
|
|
goto out_unmap;
|
|
}
|
|
|
|
offset = uaddr & ~PAGE_MASK;
|
|
for (j = cur_page; j < page_limit; j++) {
|
|
unsigned int bytes = PAGE_SIZE - offset;
|
|
|
|
if (len <= 0)
|
|
break;
|
|
|
|
if (bytes > len)
|
|
bytes = len;
|
|
|
|
/*
|
|
* sorry...
|
|
*/
|
|
if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
|
|
bytes)
|
|
break;
|
|
|
|
len -= bytes;
|
|
offset = 0;
|
|
}
|
|
|
|
cur_page = j;
|
|
/*
|
|
* release the pages we didn't map into the bio, if any
|
|
*/
|
|
while (j < page_limit)
|
|
page_cache_release(pages[j++]);
|
|
}
|
|
|
|
kfree(pages);
|
|
|
|
/*
|
|
* set data direction, and check if mapped pages need bouncing
|
|
*/
|
|
if (!write_to_vm)
|
|
bio->bi_rw |= REQ_WRITE;
|
|
|
|
bio->bi_bdev = bdev;
|
|
bio->bi_flags |= (1 << BIO_USER_MAPPED);
|
|
return bio;
|
|
|
|
out_unmap:
|
|
for (i = 0; i < nr_pages; i++) {
|
|
if(!pages[i])
|
|
break;
|
|
page_cache_release(pages[i]);
|
|
}
|
|
out:
|
|
kfree(pages);
|
|
bio_put(bio);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
/**
|
|
* bio_map_user - map user address into bio
|
|
* @q: the struct request_queue for the bio
|
|
* @bdev: destination block device
|
|
* @uaddr: start of user address
|
|
* @len: length in bytes
|
|
* @write_to_vm: bool indicating writing to pages or not
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* Map the user space address into a bio suitable for io to a block
|
|
* device. Returns an error pointer in case of error.
|
|
*/
|
|
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
|
|
unsigned long uaddr, unsigned int len, int write_to_vm,
|
|
gfp_t gfp_mask)
|
|
{
|
|
struct sg_iovec iov;
|
|
|
|
iov.iov_base = (void __user *)uaddr;
|
|
iov.iov_len = len;
|
|
|
|
return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
|
|
}
|
|
EXPORT_SYMBOL(bio_map_user);
|
|
|
|
/**
|
|
* bio_map_user_iov - map user sg_iovec table into bio
|
|
* @q: the struct request_queue for the bio
|
|
* @bdev: destination block device
|
|
* @iov: the iovec.
|
|
* @iov_count: number of elements in the iovec
|
|
* @write_to_vm: bool indicating writing to pages or not
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* Map the user space address into a bio suitable for io to a block
|
|
* device. Returns an error pointer in case of error.
|
|
*/
|
|
struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
|
|
struct sg_iovec *iov, int iov_count,
|
|
int write_to_vm, gfp_t gfp_mask)
|
|
{
|
|
struct bio *bio;
|
|
|
|
bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
|
|
gfp_mask);
|
|
if (IS_ERR(bio))
|
|
return bio;
|
|
|
|
/*
|
|
* subtle -- if __bio_map_user() ended up bouncing a bio,
|
|
* it would normally disappear when its bi_end_io is run.
|
|
* however, we need it for the unmap, so grab an extra
|
|
* reference to it
|
|
*/
|
|
bio_get(bio);
|
|
|
|
return bio;
|
|
}
|
|
|
|
static void __bio_unmap_user(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec;
|
|
int i;
|
|
|
|
/*
|
|
* make sure we dirty pages we wrote to
|
|
*/
|
|
bio_for_each_segment_all(bvec, bio, i) {
|
|
if (bio_data_dir(bio) == READ)
|
|
set_page_dirty_lock(bvec->bv_page);
|
|
|
|
page_cache_release(bvec->bv_page);
|
|
}
|
|
|
|
bio_put(bio);
|
|
}
|
|
|
|
/**
|
|
* bio_unmap_user - unmap a bio
|
|
* @bio: the bio being unmapped
|
|
*
|
|
* Unmap a bio previously mapped by bio_map_user(). Must be called with
|
|
* a process context.
|
|
*
|
|
* bio_unmap_user() may sleep.
|
|
*/
|
|
void bio_unmap_user(struct bio *bio)
|
|
{
|
|
__bio_unmap_user(bio);
|
|
bio_put(bio);
|
|
}
|
|
EXPORT_SYMBOL(bio_unmap_user);
|
|
|
|
static void bio_map_kern_endio(struct bio *bio, int err)
|
|
{
|
|
bio_put(bio);
|
|
}
|
|
|
|
static struct bio *__bio_map_kern(struct request_queue *q, void *data,
|
|
unsigned int len, gfp_t gfp_mask)
|
|
{
|
|
unsigned long kaddr = (unsigned long)data;
|
|
unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
unsigned long start = kaddr >> PAGE_SHIFT;
|
|
const int nr_pages = end - start;
|
|
int offset, i;
|
|
struct bio *bio;
|
|
|
|
bio = bio_kmalloc(gfp_mask, nr_pages);
|
|
if (!bio)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
offset = offset_in_page(kaddr);
|
|
for (i = 0; i < nr_pages; i++) {
|
|
unsigned int bytes = PAGE_SIZE - offset;
|
|
|
|
if (len <= 0)
|
|
break;
|
|
|
|
if (bytes > len)
|
|
bytes = len;
|
|
|
|
if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
|
|
offset) < bytes)
|
|
break;
|
|
|
|
data += bytes;
|
|
len -= bytes;
|
|
offset = 0;
|
|
}
|
|
|
|
bio->bi_end_io = bio_map_kern_endio;
|
|
return bio;
|
|
}
|
|
|
|
/**
|
|
* bio_map_kern - map kernel address into bio
|
|
* @q: the struct request_queue for the bio
|
|
* @data: pointer to buffer to map
|
|
* @len: length in bytes
|
|
* @gfp_mask: allocation flags for bio allocation
|
|
*
|
|
* Map the kernel address into a bio suitable for io to a block
|
|
* device. Returns an error pointer in case of error.
|
|
*/
|
|
struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
|
|
gfp_t gfp_mask)
|
|
{
|
|
struct bio *bio;
|
|
|
|
bio = __bio_map_kern(q, data, len, gfp_mask);
|
|
if (IS_ERR(bio))
|
|
return bio;
|
|
|
|
if (bio->bi_size == len)
|
|
return bio;
|
|
|
|
/*
|
|
* Don't support partial mappings.
|
|
*/
|
|
bio_put(bio);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
EXPORT_SYMBOL(bio_map_kern);
|
|
|
|
static void bio_copy_kern_endio(struct bio *bio, int err)
|
|
{
|
|
struct bio_vec *bvec;
|
|
const int read = bio_data_dir(bio) == READ;
|
|
struct bio_map_data *bmd = bio->bi_private;
|
|
int i;
|
|
char *p = bmd->sgvecs[0].iov_base;
|
|
|
|
bio_for_each_segment_all(bvec, bio, i) {
|
|
char *addr = page_address(bvec->bv_page);
|
|
int len = bmd->iovecs[i].bv_len;
|
|
|
|
if (read)
|
|
memcpy(p, addr, len);
|
|
|
|
__free_page(bvec->bv_page);
|
|
p += len;
|
|
}
|
|
|
|
bio_free_map_data(bmd);
|
|
bio_put(bio);
|
|
}
|
|
|
|
/**
|
|
* bio_copy_kern - copy kernel address into bio
|
|
* @q: the struct request_queue for the bio
|
|
* @data: pointer to buffer to copy
|
|
* @len: length in bytes
|
|
* @gfp_mask: allocation flags for bio and page allocation
|
|
* @reading: data direction is READ
|
|
*
|
|
* copy the kernel address into a bio suitable for io to a block
|
|
* device. Returns an error pointer in case of error.
|
|
*/
|
|
struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
|
|
gfp_t gfp_mask, int reading)
|
|
{
|
|
struct bio *bio;
|
|
struct bio_vec *bvec;
|
|
int i;
|
|
|
|
bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
|
|
if (IS_ERR(bio))
|
|
return bio;
|
|
|
|
if (!reading) {
|
|
void *p = data;
|
|
|
|
bio_for_each_segment_all(bvec, bio, i) {
|
|
char *addr = page_address(bvec->bv_page);
|
|
|
|
memcpy(addr, p, bvec->bv_len);
|
|
p += bvec->bv_len;
|
|
}
|
|
}
|
|
|
|
bio->bi_end_io = bio_copy_kern_endio;
|
|
|
|
return bio;
|
|
}
|
|
EXPORT_SYMBOL(bio_copy_kern);
|
|
|
|
/*
|
|
* bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
|
|
* for performing direct-IO in BIOs.
|
|
*
|
|
* The problem is that we cannot run set_page_dirty() from interrupt context
|
|
* because the required locks are not interrupt-safe. So what we can do is to
|
|
* mark the pages dirty _before_ performing IO. And in interrupt context,
|
|
* check that the pages are still dirty. If so, fine. If not, redirty them
|
|
* in process context.
|
|
*
|
|
* We special-case compound pages here: normally this means reads into hugetlb
|
|
* pages. The logic in here doesn't really work right for compound pages
|
|
* because the VM does not uniformly chase down the head page in all cases.
|
|
* But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
|
|
* handle them at all. So we skip compound pages here at an early stage.
|
|
*
|
|
* Note that this code is very hard to test under normal circumstances because
|
|
* direct-io pins the pages with get_user_pages(). This makes
|
|
* is_page_cache_freeable return false, and the VM will not clean the pages.
|
|
* But other code (eg, flusher threads) could clean the pages if they are mapped
|
|
* pagecache.
|
|
*
|
|
* Simply disabling the call to bio_set_pages_dirty() is a good way to test the
|
|
* deferred bio dirtying paths.
|
|
*/
|
|
|
|
/*
|
|
* bio_set_pages_dirty() will mark all the bio's pages as dirty.
|
|
*/
|
|
void bio_set_pages_dirty(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec;
|
|
int i;
|
|
|
|
bio_for_each_segment_all(bvec, bio, i) {
|
|
struct page *page = bvec->bv_page;
|
|
|
|
if (page && !PageCompound(page))
|
|
set_page_dirty_lock(page);
|
|
}
|
|
}
|
|
|
|
static void bio_release_pages(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec;
|
|
int i;
|
|
|
|
bio_for_each_segment_all(bvec, bio, i) {
|
|
struct page *page = bvec->bv_page;
|
|
|
|
if (page)
|
|
put_page(page);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
|
|
* If they are, then fine. If, however, some pages are clean then they must
|
|
* have been written out during the direct-IO read. So we take another ref on
|
|
* the BIO and the offending pages and re-dirty the pages in process context.
|
|
*
|
|
* It is expected that bio_check_pages_dirty() will wholly own the BIO from
|
|
* here on. It will run one page_cache_release() against each page and will
|
|
* run one bio_put() against the BIO.
|
|
*/
|
|
|
|
static void bio_dirty_fn(struct work_struct *work);
|
|
|
|
static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
|
|
static DEFINE_SPINLOCK(bio_dirty_lock);
|
|
static struct bio *bio_dirty_list;
|
|
|
|
/*
|
|
* This runs in process context
|
|
*/
|
|
static void bio_dirty_fn(struct work_struct *work)
|
|
{
|
|
unsigned long flags;
|
|
struct bio *bio;
|
|
|
|
spin_lock_irqsave(&bio_dirty_lock, flags);
|
|
bio = bio_dirty_list;
|
|
bio_dirty_list = NULL;
|
|
spin_unlock_irqrestore(&bio_dirty_lock, flags);
|
|
|
|
while (bio) {
|
|
struct bio *next = bio->bi_private;
|
|
|
|
bio_set_pages_dirty(bio);
|
|
bio_release_pages(bio);
|
|
bio_put(bio);
|
|
bio = next;
|
|
}
|
|
}
|
|
|
|
void bio_check_pages_dirty(struct bio *bio)
|
|
{
|
|
struct bio_vec *bvec;
|
|
int nr_clean_pages = 0;
|
|
int i;
|
|
|
|
bio_for_each_segment_all(bvec, bio, i) {
|
|
struct page *page = bvec->bv_page;
|
|
|
|
if (PageDirty(page) || PageCompound(page)) {
|
|
page_cache_release(page);
|
|
bvec->bv_page = NULL;
|
|
} else {
|
|
nr_clean_pages++;
|
|
}
|
|
}
|
|
|
|
if (nr_clean_pages) {
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&bio_dirty_lock, flags);
|
|
bio->bi_private = bio_dirty_list;
|
|
bio_dirty_list = bio;
|
|
spin_unlock_irqrestore(&bio_dirty_lock, flags);
|
|
schedule_work(&bio_dirty_work);
|
|
} else {
|
|
bio_put(bio);
|
|
}
|
|
}
|
|
|
|
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
|
|
void bio_flush_dcache_pages(struct bio *bi)
|
|
{
|
|
int i;
|
|
struct bio_vec *bvec;
|
|
|
|
bio_for_each_segment(bvec, bi, i)
|
|
flush_dcache_page(bvec->bv_page);
|
|
}
|
|
EXPORT_SYMBOL(bio_flush_dcache_pages);
|
|
#endif
|
|
|
|
/**
|
|
* bio_endio - end I/O on a bio
|
|
* @bio: bio
|
|
* @error: error, if any
|
|
*
|
|
* Description:
|
|
* bio_endio() will end I/O on the whole bio. bio_endio() is the
|
|
* preferred way to end I/O on a bio, it takes care of clearing
|
|
* BIO_UPTODATE on error. @error is 0 on success, and and one of the
|
|
* established -Exxxx (-EIO, for instance) error values in case
|
|
* something went wrong. No one should call bi_end_io() directly on a
|
|
* bio unless they own it and thus know that it has an end_io
|
|
* function.
|
|
**/
|
|
void bio_endio(struct bio *bio, int error)
|
|
{
|
|
if (error)
|
|
clear_bit(BIO_UPTODATE, &bio->bi_flags);
|
|
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
|
|
error = -EIO;
|
|
|
|
if (bio->bi_end_io)
|
|
bio->bi_end_io(bio, error);
|
|
}
|
|
EXPORT_SYMBOL(bio_endio);
|
|
|
|
void bio_pair_release(struct bio_pair *bp)
|
|
{
|
|
if (atomic_dec_and_test(&bp->cnt)) {
|
|
struct bio *master = bp->bio1.bi_private;
|
|
|
|
bio_endio(master, bp->error);
|
|
mempool_free(bp, bp->bio2.bi_private);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(bio_pair_release);
|
|
|
|
static void bio_pair_end_1(struct bio *bi, int err)
|
|
{
|
|
struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
|
|
|
|
if (err)
|
|
bp->error = err;
|
|
|
|
bio_pair_release(bp);
|
|
}
|
|
|
|
static void bio_pair_end_2(struct bio *bi, int err)
|
|
{
|
|
struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
|
|
|
|
if (err)
|
|
bp->error = err;
|
|
|
|
bio_pair_release(bp);
|
|
}
|
|
|
|
/*
|
|
* split a bio - only worry about a bio with a single page in its iovec
|
|
*/
|
|
struct bio_pair *bio_split(struct bio *bi, int first_sectors)
|
|
{
|
|
struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
|
|
|
|
if (!bp)
|
|
return bp;
|
|
|
|
trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
|
|
bi->bi_sector + first_sectors);
|
|
|
|
BUG_ON(bio_segments(bi) > 1);
|
|
atomic_set(&bp->cnt, 3);
|
|
bp->error = 0;
|
|
bp->bio1 = *bi;
|
|
bp->bio2 = *bi;
|
|
bp->bio2.bi_sector += first_sectors;
|
|
bp->bio2.bi_size -= first_sectors << 9;
|
|
bp->bio1.bi_size = first_sectors << 9;
|
|
|
|
if (bi->bi_vcnt != 0) {
|
|
bp->bv1 = *bio_iovec(bi);
|
|
bp->bv2 = *bio_iovec(bi);
|
|
|
|
if (bio_is_rw(bi)) {
|
|
bp->bv2.bv_offset += first_sectors << 9;
|
|
bp->bv2.bv_len -= first_sectors << 9;
|
|
bp->bv1.bv_len = first_sectors << 9;
|
|
}
|
|
|
|
bp->bio1.bi_io_vec = &bp->bv1;
|
|
bp->bio2.bi_io_vec = &bp->bv2;
|
|
|
|
bp->bio1.bi_max_vecs = 1;
|
|
bp->bio2.bi_max_vecs = 1;
|
|
}
|
|
|
|
bp->bio1.bi_end_io = bio_pair_end_1;
|
|
bp->bio2.bi_end_io = bio_pair_end_2;
|
|
|
|
bp->bio1.bi_private = bi;
|
|
bp->bio2.bi_private = bio_split_pool;
|
|
|
|
if (bio_integrity(bi))
|
|
bio_integrity_split(bi, bp, first_sectors);
|
|
|
|
return bp;
|
|
}
|
|
EXPORT_SYMBOL(bio_split);
|
|
|
|
/**
|
|
* bio_sector_offset - Find hardware sector offset in bio
|
|
* @bio: bio to inspect
|
|
* @index: bio_vec index
|
|
* @offset: offset in bv_page
|
|
*
|
|
* Return the number of hardware sectors between beginning of bio
|
|
* and an end point indicated by a bio_vec index and an offset
|
|
* within that vector's page.
|
|
*/
|
|
sector_t bio_sector_offset(struct bio *bio, unsigned short index,
|
|
unsigned int offset)
|
|
{
|
|
unsigned int sector_sz;
|
|
struct bio_vec *bv;
|
|
sector_t sectors;
|
|
int i;
|
|
|
|
sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
|
|
sectors = 0;
|
|
|
|
if (index >= bio->bi_idx)
|
|
index = bio->bi_vcnt - 1;
|
|
|
|
bio_for_each_segment_all(bv, bio, i) {
|
|
if (i == index) {
|
|
if (offset > bv->bv_offset)
|
|
sectors += (offset - bv->bv_offset) / sector_sz;
|
|
break;
|
|
}
|
|
|
|
sectors += bv->bv_len / sector_sz;
|
|
}
|
|
|
|
return sectors;
|
|
}
|
|
EXPORT_SYMBOL(bio_sector_offset);
|
|
|
|
/*
|
|
* create memory pools for biovec's in a bio_set.
|
|
* use the global biovec slabs created for general use.
|
|
*/
|
|
mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries)
|
|
{
|
|
struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
|
|
|
|
return mempool_create_slab_pool(pool_entries, bp->slab);
|
|
}
|
|
|
|
void bioset_free(struct bio_set *bs)
|
|
{
|
|
if (bs->rescue_workqueue)
|
|
destroy_workqueue(bs->rescue_workqueue);
|
|
|
|
if (bs->bio_pool)
|
|
mempool_destroy(bs->bio_pool);
|
|
|
|
if (bs->bvec_pool)
|
|
mempool_destroy(bs->bvec_pool);
|
|
|
|
bioset_integrity_free(bs);
|
|
bio_put_slab(bs);
|
|
|
|
kfree(bs);
|
|
}
|
|
EXPORT_SYMBOL(bioset_free);
|
|
|
|
/**
|
|
* bioset_create - Create a bio_set
|
|
* @pool_size: Number of bio and bio_vecs to cache in the mempool
|
|
* @front_pad: Number of bytes to allocate in front of the returned bio
|
|
*
|
|
* Description:
|
|
* Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
|
|
* to ask for a number of bytes to be allocated in front of the bio.
|
|
* Front pad allocation is useful for embedding the bio inside
|
|
* another structure, to avoid allocating extra data to go with the bio.
|
|
* Note that the bio must be embedded at the END of that structure always,
|
|
* or things will break badly.
|
|
*/
|
|
struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
|
|
{
|
|
unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
|
|
struct bio_set *bs;
|
|
|
|
bs = kzalloc(sizeof(*bs), GFP_KERNEL);
|
|
if (!bs)
|
|
return NULL;
|
|
|
|
bs->front_pad = front_pad;
|
|
|
|
spin_lock_init(&bs->rescue_lock);
|
|
bio_list_init(&bs->rescue_list);
|
|
INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
|
|
|
|
bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
|
|
if (!bs->bio_slab) {
|
|
kfree(bs);
|
|
return NULL;
|
|
}
|
|
|
|
bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
|
|
if (!bs->bio_pool)
|
|
goto bad;
|
|
|
|
bs->bvec_pool = biovec_create_pool(bs, pool_size);
|
|
if (!bs->bvec_pool)
|
|
goto bad;
|
|
|
|
bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
|
|
if (!bs->rescue_workqueue)
|
|
goto bad;
|
|
|
|
return bs;
|
|
bad:
|
|
bioset_free(bs);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(bioset_create);
|
|
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
/**
|
|
* bio_associate_current - associate a bio with %current
|
|
* @bio: target bio
|
|
*
|
|
* Associate @bio with %current if it hasn't been associated yet. Block
|
|
* layer will treat @bio as if it were issued by %current no matter which
|
|
* task actually issues it.
|
|
*
|
|
* This function takes an extra reference of @task's io_context and blkcg
|
|
* which will be put when @bio is released. The caller must own @bio,
|
|
* ensure %current->io_context exists, and is responsible for synchronizing
|
|
* calls to this function.
|
|
*/
|
|
int bio_associate_current(struct bio *bio)
|
|
{
|
|
struct io_context *ioc;
|
|
struct cgroup_subsys_state *css;
|
|
|
|
if (bio->bi_ioc)
|
|
return -EBUSY;
|
|
|
|
ioc = current->io_context;
|
|
if (!ioc)
|
|
return -ENOENT;
|
|
|
|
/* acquire active ref on @ioc and associate */
|
|
get_io_context_active(ioc);
|
|
bio->bi_ioc = ioc;
|
|
|
|
/* associate blkcg if exists */
|
|
rcu_read_lock();
|
|
css = task_subsys_state(current, blkio_subsys_id);
|
|
if (css && css_tryget(css))
|
|
bio->bi_css = css;
|
|
rcu_read_unlock();
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* bio_disassociate_task - undo bio_associate_current()
|
|
* @bio: target bio
|
|
*/
|
|
void bio_disassociate_task(struct bio *bio)
|
|
{
|
|
if (bio->bi_ioc) {
|
|
put_io_context(bio->bi_ioc);
|
|
bio->bi_ioc = NULL;
|
|
}
|
|
if (bio->bi_css) {
|
|
css_put(bio->bi_css);
|
|
bio->bi_css = NULL;
|
|
}
|
|
}
|
|
|
|
#endif /* CONFIG_BLK_CGROUP */
|
|
|
|
static void __init biovec_init_slabs(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < BIOVEC_NR_POOLS; i++) {
|
|
int size;
|
|
struct biovec_slab *bvs = bvec_slabs + i;
|
|
|
|
if (bvs->nr_vecs <= BIO_INLINE_VECS) {
|
|
bvs->slab = NULL;
|
|
continue;
|
|
}
|
|
|
|
size = bvs->nr_vecs * sizeof(struct bio_vec);
|
|
bvs->slab = kmem_cache_create(bvs->name, size, 0,
|
|
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
|
|
}
|
|
}
|
|
|
|
static int __init init_bio(void)
|
|
{
|
|
bio_slab_max = 2;
|
|
bio_slab_nr = 0;
|
|
bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
|
|
if (!bio_slabs)
|
|
panic("bio: can't allocate bios\n");
|
|
|
|
bio_integrity_init();
|
|
biovec_init_slabs();
|
|
|
|
fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
|
|
if (!fs_bio_set)
|
|
panic("bio: can't allocate bios\n");
|
|
|
|
if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
|
|
panic("bio: can't create integrity pool\n");
|
|
|
|
bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
|
|
sizeof(struct bio_pair));
|
|
if (!bio_split_pool)
|
|
panic("bio: can't create split pool\n");
|
|
|
|
return 0;
|
|
}
|
|
subsys_initcall(init_bio);
|