linux/drivers/nvdimm/pmem.c
Dan Williams f284a4f237 libnvdimm: introduce nvdimm_flush() and nvdimm_has_flush()
nvdimm_flush() is a replacement for the x86 'pcommit' instruction.  It is
an optional write flushing mechanism that an nvdimm bus can provide for
the pmem driver to consume.  In the case of the NFIT nvdimm-bus-provider
nvdimm_flush() is implemented as a series of flush-hint-address [1]
writes to each dimm in the interleave set (region) that backs the
namespace.

The nvdimm_has_flush() routine relies on platform firmware to describe
the flushing capabilities of a platform.  It uses the heuristic of
whether an nvdimm bus provider provides flush address data to return a
ternary result:

      1: flush addresses defined
      0: dimm topology described without flush addresses (assume ADR)
 -errno: no topology information, unable to determine flush mechanism

The pmem driver is expected to take the following actions on this ternary
result:

      1: nvdimm_flush() in response to REQ_FUA / REQ_FLUSH and shutdown
      0: do not set, WC or FUA on the queue, take no further action
 -errno: warn and then operate as if nvdimm_has_flush() returned '0'

The caveat of this heuristic is that it can not distinguish the "dimm
does not have flush address" case from the "platform firmware is broken
and failed to describe a flush address".  Given we are already
explicitly trusting the NFIT there's not much more we can do beyond
blacklisting broken firmwares if they are ever encountered.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-11 16:13:42 -07:00

406 lines
11 KiB
C

/*
* Persistent Memory Driver
*
* Copyright (c) 2014-2015, Intel Corporation.
* Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
* Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
#include <asm/cacheflush.h>
#include <linux/blkdev.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/badblocks.h>
#include <linux/memremap.h>
#include <linux/vmalloc.h>
#include <linux/pfn_t.h>
#include <linux/slab.h>
#include <linux/pmem.h>
#include <linux/nd.h>
#include "pmem.h"
#include "pfn.h"
#include "nd.h"
static struct device *to_dev(struct pmem_device *pmem)
{
/*
* nvdimm bus services need a 'dev' parameter, and we record the device
* at init in bb.dev.
*/
return pmem->bb.dev;
}
static struct nd_region *to_region(struct pmem_device *pmem)
{
return to_nd_region(to_dev(pmem)->parent);
}
static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
unsigned int len)
{
struct device *dev = to_dev(pmem);
sector_t sector;
long cleared;
sector = (offset - pmem->data_offset) / 512;
cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
if (cleared > 0 && cleared / 512) {
dev_dbg(dev, "%s: %llx clear %ld sector%s\n",
__func__, (unsigned long long) sector,
cleared / 512, cleared / 512 > 1 ? "s" : "");
badblocks_clear(&pmem->bb, sector, cleared / 512);
}
invalidate_pmem(pmem->virt_addr + offset, len);
}
static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
unsigned int len, unsigned int off, int rw,
sector_t sector)
{
int rc = 0;
bool bad_pmem = false;
void *mem = kmap_atomic(page);
phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
bad_pmem = true;
if (rw == READ) {
if (unlikely(bad_pmem))
rc = -EIO;
else {
rc = memcpy_from_pmem(mem + off, pmem_addr, len);
flush_dcache_page(page);
}
} else {
/*
* Note that we write the data both before and after
* clearing poison. The write before clear poison
* handles situations where the latest written data is
* preserved and the clear poison operation simply marks
* the address range as valid without changing the data.
* In this case application software can assume that an
* interrupted write will either return the new good
* data or an error.
*
* However, if pmem_clear_poison() leaves the data in an
* indeterminate state we need to perform the write
* after clear poison.
*/
flush_dcache_page(page);
memcpy_to_pmem(pmem_addr, mem + off, len);
if (unlikely(bad_pmem)) {
pmem_clear_poison(pmem, pmem_off, len);
memcpy_to_pmem(pmem_addr, mem + off, len);
}
}
kunmap_atomic(mem);
return rc;
}
static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
{
int rc = 0;
bool do_acct;
unsigned long start;
struct bio_vec bvec;
struct bvec_iter iter;
struct pmem_device *pmem = q->queuedata;
do_acct = nd_iostat_start(bio, &start);
bio_for_each_segment(bvec, bio, iter) {
rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
bvec.bv_offset, bio_data_dir(bio),
iter.bi_sector);
if (rc) {
bio->bi_error = rc;
break;
}
}
if (do_acct)
nd_iostat_end(bio, start);
if (bio_data_dir(bio))
nvdimm_flush(to_region(pmem));
bio_endio(bio);
return BLK_QC_T_NONE;
}
static int pmem_rw_page(struct block_device *bdev, sector_t sector,
struct page *page, int rw)
{
struct pmem_device *pmem = bdev->bd_queue->queuedata;
int rc;
rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, rw, sector);
if (rw & WRITE)
nvdimm_flush(to_region(pmem));
/*
* The ->rw_page interface is subtle and tricky. The core
* retries on any error, so we can only invoke page_endio() in
* the successful completion case. Otherwise, we'll see crashes
* caused by double completion.
*/
if (rc == 0)
page_endio(page, rw & WRITE, 0);
return rc;
}
/* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
__weak long pmem_direct_access(struct block_device *bdev, sector_t sector,
void __pmem **kaddr, pfn_t *pfn, long size)
{
struct pmem_device *pmem = bdev->bd_queue->queuedata;
resource_size_t offset = sector * 512 + pmem->data_offset;
if (unlikely(is_bad_pmem(&pmem->bb, sector, size)))
return -EIO;
*kaddr = pmem->virt_addr + offset;
*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
/*
* If badblocks are present, limit known good range to the
* requested range.
*/
if (unlikely(pmem->bb.count))
return size;
return pmem->size - pmem->pfn_pad - offset;
}
static const struct block_device_operations pmem_fops = {
.owner = THIS_MODULE,
.rw_page = pmem_rw_page,
.direct_access = pmem_direct_access,
.revalidate_disk = nvdimm_revalidate_disk,
};
static void pmem_release_queue(void *q)
{
blk_cleanup_queue(q);
}
static void pmem_release_disk(void *disk)
{
del_gendisk(disk);
put_disk(disk);
}
static int pmem_attach_disk(struct device *dev,
struct nd_namespace_common *ndns)
{
struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
struct nd_region *nd_region = to_nd_region(dev->parent);
struct vmem_altmap __altmap, *altmap = NULL;
struct resource *res = &nsio->res;
struct nd_pfn *nd_pfn = NULL;
int nid = dev_to_node(dev);
struct nd_pfn_sb *pfn_sb;
struct pmem_device *pmem;
struct resource pfn_res;
struct request_queue *q;
struct gendisk *disk;
void *addr;
/* while nsio_rw_bytes is active, parse a pfn info block if present */
if (is_nd_pfn(dev)) {
nd_pfn = to_nd_pfn(dev);
altmap = nvdimm_setup_pfn(nd_pfn, &pfn_res, &__altmap);
if (IS_ERR(altmap))
return PTR_ERR(altmap);
}
/* we're attaching a block device, disable raw namespace access */
devm_nsio_disable(dev, nsio);
pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
if (!pmem)
return -ENOMEM;
dev_set_drvdata(dev, pmem);
pmem->phys_addr = res->start;
pmem->size = resource_size(res);
if (nvdimm_has_flush(nd_region) < 0)
dev_warn(dev, "unable to guarantee persistence of writes\n");
if (!devm_request_mem_region(dev, res->start, resource_size(res),
dev_name(dev))) {
dev_warn(dev, "could not reserve region %pR\n", res);
return -EBUSY;
}
q = blk_alloc_queue_node(GFP_KERNEL, dev_to_node(dev));
if (!q)
return -ENOMEM;
pmem->pfn_flags = PFN_DEV;
if (is_nd_pfn(dev)) {
addr = devm_memremap_pages(dev, &pfn_res, &q->q_usage_counter,
altmap);
pfn_sb = nd_pfn->pfn_sb;
pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
pmem->pfn_pad = resource_size(res) - resource_size(&pfn_res);
pmem->pfn_flags |= PFN_MAP;
res = &pfn_res; /* for badblocks populate */
res->start += pmem->data_offset;
} else if (pmem_should_map_pages(dev)) {
addr = devm_memremap_pages(dev, &nsio->res,
&q->q_usage_counter, NULL);
pmem->pfn_flags |= PFN_MAP;
} else
addr = devm_memremap(dev, pmem->phys_addr,
pmem->size, ARCH_MEMREMAP_PMEM);
/*
* At release time the queue must be dead before
* devm_memremap_pages is unwound
*/
if (devm_add_action_or_reset(dev, pmem_release_queue, q))
return -ENOMEM;
if (IS_ERR(addr))
return PTR_ERR(addr);
pmem->virt_addr = (void __pmem *) addr;
blk_queue_make_request(q, pmem_make_request);
blk_queue_physical_block_size(q, PAGE_SIZE);
blk_queue_max_hw_sectors(q, UINT_MAX);
blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
q->queuedata = pmem;
disk = alloc_disk_node(0, nid);
if (!disk)
return -ENOMEM;
disk->fops = &pmem_fops;
disk->queue = q;
disk->flags = GENHD_FL_EXT_DEVT;
nvdimm_namespace_disk_name(ndns, disk->disk_name);
disk->driverfs_dev = dev;
set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
/ 512);
if (devm_init_badblocks(dev, &pmem->bb))
return -ENOMEM;
nvdimm_badblocks_populate(nd_region, &pmem->bb, res);
disk->bb = &pmem->bb;
add_disk(disk);
if (devm_add_action_or_reset(dev, pmem_release_disk, disk))
return -ENOMEM;
revalidate_disk(disk);
return 0;
}
static int nd_pmem_probe(struct device *dev)
{
struct nd_namespace_common *ndns;
ndns = nvdimm_namespace_common_probe(dev);
if (IS_ERR(ndns))
return PTR_ERR(ndns);
if (devm_nsio_enable(dev, to_nd_namespace_io(&ndns->dev)))
return -ENXIO;
if (is_nd_btt(dev))
return nvdimm_namespace_attach_btt(ndns);
if (is_nd_pfn(dev))
return pmem_attach_disk(dev, ndns);
/* if we find a valid info-block we'll come back as that personality */
if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0
|| nd_dax_probe(dev, ndns) == 0)
return -ENXIO;
/* ...otherwise we're just a raw pmem device */
return pmem_attach_disk(dev, ndns);
}
static int nd_pmem_remove(struct device *dev)
{
if (is_nd_btt(dev))
nvdimm_namespace_detach_btt(to_nd_btt(dev));
return 0;
}
static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
{
struct pmem_device *pmem = dev_get_drvdata(dev);
struct nd_region *nd_region = to_region(pmem);
resource_size_t offset = 0, end_trunc = 0;
struct nd_namespace_common *ndns;
struct nd_namespace_io *nsio;
struct resource res;
if (event != NVDIMM_REVALIDATE_POISON)
return;
if (is_nd_btt(dev)) {
struct nd_btt *nd_btt = to_nd_btt(dev);
ndns = nd_btt->ndns;
} else if (is_nd_pfn(dev)) {
struct nd_pfn *nd_pfn = to_nd_pfn(dev);
struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
ndns = nd_pfn->ndns;
offset = pmem->data_offset + __le32_to_cpu(pfn_sb->start_pad);
end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
} else
ndns = to_ndns(dev);
nsio = to_nd_namespace_io(&ndns->dev);
res.start = nsio->res.start + offset;
res.end = nsio->res.end - end_trunc;
nvdimm_badblocks_populate(nd_region, &pmem->bb, &res);
}
MODULE_ALIAS("pmem");
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
static struct nd_device_driver nd_pmem_driver = {
.probe = nd_pmem_probe,
.remove = nd_pmem_remove,
.notify = nd_pmem_notify,
.drv = {
.name = "nd_pmem",
},
.type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
};
static int __init pmem_init(void)
{
return nd_driver_register(&nd_pmem_driver);
}
module_init(pmem_init);
static void pmem_exit(void)
{
driver_unregister(&nd_pmem_driver.drv);
}
module_exit(pmem_exit);
MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
MODULE_LICENSE("GPL v2");