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972248e911
We can just stash away the second request in struct bsg_job instead of using the block layer req->next_rq field, allowing for the eventual removal of the latter. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
527 lines
11 KiB
C
527 lines
11 KiB
C
/*
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* bsg.c - block layer implementation of the sg v4 interface
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*
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* Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs
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* Copyright (C) 2004 Peter M. Jones <pjones@redhat.com>
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License version 2. See the file "COPYING" in the main directory of this
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* archive for more details.
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*
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/file.h>
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#include <linux/blkdev.h>
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#include <linux/cdev.h>
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#include <linux/jiffies.h>
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#include <linux/percpu.h>
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#include <linux/idr.h>
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#include <linux/bsg.h>
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#include <linux/slab.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_ioctl.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_driver.h>
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#include <scsi/sg.h>
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#define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver"
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#define BSG_VERSION "0.4"
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#define bsg_dbg(bd, fmt, ...) \
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pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__)
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struct bsg_device {
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struct request_queue *queue;
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spinlock_t lock;
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struct hlist_node dev_list;
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refcount_t ref_count;
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char name[20];
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int max_queue;
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};
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#define BSG_DEFAULT_CMDS 64
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#define BSG_MAX_DEVS 32768
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static DEFINE_MUTEX(bsg_mutex);
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static DEFINE_IDR(bsg_minor_idr);
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#define BSG_LIST_ARRAY_SIZE 8
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static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE];
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static struct class *bsg_class;
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static int bsg_major;
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static inline struct hlist_head *bsg_dev_idx_hash(int index)
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{
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return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)];
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}
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#define uptr64(val) ((void __user *)(uintptr_t)(val))
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static int bsg_scsi_check_proto(struct sg_io_v4 *hdr)
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{
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if (hdr->protocol != BSG_PROTOCOL_SCSI ||
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hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
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return -EINVAL;
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return 0;
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}
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static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
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fmode_t mode)
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{
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struct scsi_request *sreq = scsi_req(rq);
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if (hdr->dout_xfer_len && hdr->din_xfer_len) {
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pr_warn_once("BIDI support in bsg has been removed.\n");
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return -EOPNOTSUPP;
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}
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sreq->cmd_len = hdr->request_len;
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if (sreq->cmd_len > BLK_MAX_CDB) {
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sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
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if (!sreq->cmd)
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return -ENOMEM;
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}
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if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
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return -EFAULT;
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if (blk_verify_command(sreq->cmd, mode))
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return -EPERM;
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return 0;
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}
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static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
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{
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struct scsi_request *sreq = scsi_req(rq);
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int ret = 0;
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/*
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* fill in all the output members
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*/
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hdr->device_status = sreq->result & 0xff;
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hdr->transport_status = host_byte(sreq->result);
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hdr->driver_status = driver_byte(sreq->result);
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hdr->info = 0;
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if (hdr->device_status || hdr->transport_status || hdr->driver_status)
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hdr->info |= SG_INFO_CHECK;
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hdr->response_len = 0;
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if (sreq->sense_len && hdr->response) {
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int len = min_t(unsigned int, hdr->max_response_len,
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sreq->sense_len);
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if (copy_to_user(uptr64(hdr->response), sreq->sense, len))
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ret = -EFAULT;
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else
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hdr->response_len = len;
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}
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if (rq_data_dir(rq) == READ)
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hdr->din_resid = sreq->resid_len;
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else
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hdr->dout_resid = sreq->resid_len;
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return ret;
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}
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static void bsg_scsi_free_rq(struct request *rq)
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{
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scsi_req_free_cmd(scsi_req(rq));
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}
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static const struct bsg_ops bsg_scsi_ops = {
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.check_proto = bsg_scsi_check_proto,
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.fill_hdr = bsg_scsi_fill_hdr,
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.complete_rq = bsg_scsi_complete_rq,
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.free_rq = bsg_scsi_free_rq,
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};
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static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
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{
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struct request *rq;
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struct bio *bio;
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struct sg_io_v4 hdr;
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int ret;
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if (copy_from_user(&hdr, uarg, sizeof(hdr)))
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return -EFAULT;
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if (!q->bsg_dev.class_dev)
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return -ENXIO;
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if (hdr.guard != 'Q')
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return -EINVAL;
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ret = q->bsg_dev.ops->check_proto(&hdr);
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if (ret)
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return ret;
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rq = blk_get_request(q, hdr.dout_xfer_len ?
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REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
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if (IS_ERR(rq))
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return PTR_ERR(rq);
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ret = q->bsg_dev.ops->fill_hdr(rq, &hdr, mode);
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if (ret)
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return ret;
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rq->timeout = msecs_to_jiffies(hdr.timeout);
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if (!rq->timeout)
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rq->timeout = q->sg_timeout;
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if (!rq->timeout)
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rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
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if (rq->timeout < BLK_MIN_SG_TIMEOUT)
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rq->timeout = BLK_MIN_SG_TIMEOUT;
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if (hdr.dout_xfer_len) {
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ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.dout_xferp),
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hdr.dout_xfer_len, GFP_KERNEL);
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} else if (hdr.din_xfer_len) {
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ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.din_xferp),
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hdr.din_xfer_len, GFP_KERNEL);
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}
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if (ret)
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goto out_free_rq;
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bio = rq->bio;
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blk_execute_rq(q, NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL));
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ret = rq->q->bsg_dev.ops->complete_rq(rq, &hdr);
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blk_rq_unmap_user(bio);
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out_free_rq:
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rq->q->bsg_dev.ops->free_rq(rq);
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blk_put_request(rq);
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if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
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return -EFAULT;
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return ret;
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}
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static struct bsg_device *bsg_alloc_device(void)
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{
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struct bsg_device *bd;
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bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
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if (unlikely(!bd))
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return NULL;
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spin_lock_init(&bd->lock);
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bd->max_queue = BSG_DEFAULT_CMDS;
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INIT_HLIST_NODE(&bd->dev_list);
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return bd;
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}
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static int bsg_put_device(struct bsg_device *bd)
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{
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struct request_queue *q = bd->queue;
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mutex_lock(&bsg_mutex);
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if (!refcount_dec_and_test(&bd->ref_count)) {
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mutex_unlock(&bsg_mutex);
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return 0;
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}
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hlist_del(&bd->dev_list);
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mutex_unlock(&bsg_mutex);
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bsg_dbg(bd, "tearing down\n");
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/*
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* close can always block
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*/
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kfree(bd);
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blk_put_queue(q);
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return 0;
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}
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static struct bsg_device *bsg_add_device(struct inode *inode,
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struct request_queue *rq,
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struct file *file)
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{
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struct bsg_device *bd;
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unsigned char buf[32];
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lockdep_assert_held(&bsg_mutex);
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if (!blk_get_queue(rq))
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return ERR_PTR(-ENXIO);
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bd = bsg_alloc_device();
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if (!bd) {
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blk_put_queue(rq);
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return ERR_PTR(-ENOMEM);
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}
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bd->queue = rq;
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refcount_set(&bd->ref_count, 1);
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hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
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strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
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bsg_dbg(bd, "bound to <%s>, max queue %d\n",
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format_dev_t(buf, inode->i_rdev), bd->max_queue);
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return bd;
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}
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static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
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{
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struct bsg_device *bd;
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lockdep_assert_held(&bsg_mutex);
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hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
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if (bd->queue == q) {
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refcount_inc(&bd->ref_count);
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goto found;
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}
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}
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bd = NULL;
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found:
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return bd;
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}
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static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
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{
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struct bsg_device *bd;
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struct bsg_class_device *bcd;
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/*
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* find the class device
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*/
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mutex_lock(&bsg_mutex);
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bcd = idr_find(&bsg_minor_idr, iminor(inode));
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if (!bcd) {
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bd = ERR_PTR(-ENODEV);
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goto out_unlock;
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}
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bd = __bsg_get_device(iminor(inode), bcd->queue);
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if (!bd)
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bd = bsg_add_device(inode, bcd->queue, file);
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out_unlock:
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mutex_unlock(&bsg_mutex);
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return bd;
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}
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static int bsg_open(struct inode *inode, struct file *file)
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{
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struct bsg_device *bd;
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bd = bsg_get_device(inode, file);
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if (IS_ERR(bd))
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return PTR_ERR(bd);
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file->private_data = bd;
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return 0;
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}
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static int bsg_release(struct inode *inode, struct file *file)
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{
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struct bsg_device *bd = file->private_data;
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file->private_data = NULL;
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return bsg_put_device(bd);
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}
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static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)
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{
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return put_user(bd->max_queue, uarg);
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}
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static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)
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{
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int queue;
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if (get_user(queue, uarg))
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return -EFAULT;
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if (queue < 1)
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return -EINVAL;
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spin_lock_irq(&bd->lock);
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bd->max_queue = queue;
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spin_unlock_irq(&bd->lock);
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return 0;
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}
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static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct bsg_device *bd = file->private_data;
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void __user *uarg = (void __user *) arg;
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switch (cmd) {
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/*
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* Our own ioctls
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*/
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case SG_GET_COMMAND_Q:
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return bsg_get_command_q(bd, uarg);
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case SG_SET_COMMAND_Q:
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return bsg_set_command_q(bd, uarg);
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/*
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* SCSI/sg ioctls
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*/
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case SG_GET_VERSION_NUM:
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case SCSI_IOCTL_GET_IDLUN:
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case SCSI_IOCTL_GET_BUS_NUMBER:
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case SG_SET_TIMEOUT:
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case SG_GET_TIMEOUT:
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case SG_GET_RESERVED_SIZE:
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case SG_SET_RESERVED_SIZE:
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case SG_EMULATED_HOST:
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case SCSI_IOCTL_SEND_COMMAND:
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return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
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case SG_IO:
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return bsg_sg_io(bd->queue, file->f_mode, uarg);
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default:
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return -ENOTTY;
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}
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}
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static const struct file_operations bsg_fops = {
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.open = bsg_open,
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.release = bsg_release,
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.unlocked_ioctl = bsg_ioctl,
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.owner = THIS_MODULE,
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.llseek = default_llseek,
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};
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void bsg_unregister_queue(struct request_queue *q)
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{
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struct bsg_class_device *bcd = &q->bsg_dev;
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if (!bcd->class_dev)
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return;
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mutex_lock(&bsg_mutex);
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idr_remove(&bsg_minor_idr, bcd->minor);
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if (q->kobj.sd)
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sysfs_remove_link(&q->kobj, "bsg");
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device_unregister(bcd->class_dev);
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bcd->class_dev = NULL;
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mutex_unlock(&bsg_mutex);
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}
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EXPORT_SYMBOL_GPL(bsg_unregister_queue);
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int bsg_register_queue(struct request_queue *q, struct device *parent,
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const char *name, const struct bsg_ops *ops)
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{
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struct bsg_class_device *bcd;
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dev_t dev;
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int ret;
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struct device *class_dev = NULL;
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/*
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* we need a proper transport to send commands, not a stacked device
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*/
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if (!queue_is_mq(q))
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return 0;
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bcd = &q->bsg_dev;
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memset(bcd, 0, sizeof(*bcd));
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mutex_lock(&bsg_mutex);
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ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
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if (ret < 0) {
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if (ret == -ENOSPC) {
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printk(KERN_ERR "bsg: too many bsg devices\n");
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ret = -EINVAL;
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}
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goto unlock;
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}
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bcd->minor = ret;
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bcd->queue = q;
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bcd->ops = ops;
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dev = MKDEV(bsg_major, bcd->minor);
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class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name);
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if (IS_ERR(class_dev)) {
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ret = PTR_ERR(class_dev);
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goto idr_remove;
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}
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bcd->class_dev = class_dev;
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if (q->kobj.sd) {
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ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
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if (ret)
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goto unregister_class_dev;
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}
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mutex_unlock(&bsg_mutex);
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return 0;
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unregister_class_dev:
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device_unregister(class_dev);
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idr_remove:
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idr_remove(&bsg_minor_idr, bcd->minor);
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unlock:
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mutex_unlock(&bsg_mutex);
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return ret;
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}
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int bsg_scsi_register_queue(struct request_queue *q, struct device *parent)
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{
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if (!blk_queue_scsi_passthrough(q)) {
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WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
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return -EINVAL;
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}
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return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops);
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}
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EXPORT_SYMBOL_GPL(bsg_scsi_register_queue);
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static struct cdev bsg_cdev;
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static char *bsg_devnode(struct device *dev, umode_t *mode)
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{
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return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
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}
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static int __init bsg_init(void)
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{
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int ret, i;
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dev_t devid;
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for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
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INIT_HLIST_HEAD(&bsg_device_list[i]);
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bsg_class = class_create(THIS_MODULE, "bsg");
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if (IS_ERR(bsg_class))
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return PTR_ERR(bsg_class);
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bsg_class->devnode = bsg_devnode;
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ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
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if (ret)
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goto destroy_bsg_class;
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bsg_major = MAJOR(devid);
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cdev_init(&bsg_cdev, &bsg_fops);
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ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
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if (ret)
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goto unregister_chrdev;
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printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
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" loaded (major %d)\n", bsg_major);
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return 0;
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unregister_chrdev:
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|
unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
|
|
destroy_bsg_class:
|
|
class_destroy(bsg_class);
|
|
return ret;
|
|
}
|
|
|
|
MODULE_AUTHOR("Jens Axboe");
|
|
MODULE_DESCRIPTION(BSG_DESCRIPTION);
|
|
MODULE_LICENSE("GPL");
|
|
|
|
device_initcall(bsg_init);
|