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![Peter Zijlstra](/assets/img/avatar_default.png)
It took me a few tries to figure out what this code did; lets rewrite it into a more regular form. The thing that makes this one 'special' is the BSG_F_BLOCK flag, if that is not set we're not supposed/allowed to block and should spin wait for completion. The (new) io_wait_event() will never see a false condition in case of the spinning and we will therefore not block. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@fb.com>
1097 lines
23 KiB
C
1097 lines
23 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/poll.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/uio.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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struct bsg_device {
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struct request_queue *queue;
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spinlock_t lock;
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struct list_head busy_list;
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struct list_head done_list;
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struct hlist_node dev_list;
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atomic_t ref_count;
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int queued_cmds;
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int done_cmds;
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wait_queue_head_t wq_done;
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wait_queue_head_t wq_free;
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char name[20];
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int max_queue;
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unsigned long flags;
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};
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enum {
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BSG_F_BLOCK = 1,
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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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#undef BSG_DEBUG
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#ifdef BSG_DEBUG
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#define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args)
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#else
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#define dprintk(fmt, args...)
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#endif
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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 struct kmem_cache *bsg_cmd_cachep;
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/*
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* our internal command type
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*/
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struct bsg_command {
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struct bsg_device *bd;
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struct list_head list;
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struct request *rq;
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struct bio *bio;
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struct bio *bidi_bio;
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int err;
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struct sg_io_v4 hdr;
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char sense[SCSI_SENSE_BUFFERSIZE];
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};
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static void bsg_free_command(struct bsg_command *bc)
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{
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struct bsg_device *bd = bc->bd;
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unsigned long flags;
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kmem_cache_free(bsg_cmd_cachep, bc);
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spin_lock_irqsave(&bd->lock, flags);
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bd->queued_cmds--;
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spin_unlock_irqrestore(&bd->lock, flags);
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wake_up(&bd->wq_free);
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}
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static struct bsg_command *bsg_alloc_command(struct bsg_device *bd)
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{
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struct bsg_command *bc = ERR_PTR(-EINVAL);
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spin_lock_irq(&bd->lock);
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if (bd->queued_cmds >= bd->max_queue)
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goto out;
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bd->queued_cmds++;
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spin_unlock_irq(&bd->lock);
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bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL);
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if (unlikely(!bc)) {
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spin_lock_irq(&bd->lock);
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bd->queued_cmds--;
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bc = ERR_PTR(-ENOMEM);
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goto out;
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}
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bc->bd = bd;
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INIT_LIST_HEAD(&bc->list);
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dprintk("%s: returning free cmd %p\n", bd->name, bc);
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return bc;
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out:
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spin_unlock_irq(&bd->lock);
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return bc;
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}
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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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static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
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struct sg_io_v4 *hdr, struct bsg_device *bd,
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fmode_t has_write_perm)
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{
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if (hdr->request_len > BLK_MAX_CDB) {
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rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
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if (!rq->cmd)
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return -ENOMEM;
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}
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if (copy_from_user(rq->cmd, (void __user *)(unsigned long)hdr->request,
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hdr->request_len))
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return -EFAULT;
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if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
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if (blk_verify_command(rq->cmd, has_write_perm))
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return -EPERM;
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} else if (!capable(CAP_SYS_RAWIO))
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return -EPERM;
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/*
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* fill in request structure
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*/
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rq->cmd_len = hdr->request_len;
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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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return 0;
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}
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/*
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* Check if sg_io_v4 from user is allowed and valid
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*/
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static int
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bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
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{
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int ret = 0;
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if (hdr->guard != 'Q')
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return -EINVAL;
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switch (hdr->protocol) {
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case BSG_PROTOCOL_SCSI:
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switch (hdr->subprotocol) {
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case BSG_SUB_PROTOCOL_SCSI_CMD:
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case BSG_SUB_PROTOCOL_SCSI_TRANSPORT:
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break;
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default:
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ret = -EINVAL;
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}
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break;
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default:
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ret = -EINVAL;
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}
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*rw = hdr->dout_xfer_len ? WRITE : READ;
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return ret;
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}
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/*
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* map sg_io_v4 to a request.
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*/
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static struct request *
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bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm,
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u8 *sense)
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{
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struct request_queue *q = bd->queue;
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struct request *rq, *next_rq = NULL;
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int ret, rw;
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unsigned int dxfer_len;
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void __user *dxferp = NULL;
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struct bsg_class_device *bcd = &q->bsg_dev;
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/* if the LLD has been removed then the bsg_unregister_queue will
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* eventually be called and the class_dev was freed, so we can no
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* longer use this request_queue. Return no such address.
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*/
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if (!bcd->class_dev)
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return ERR_PTR(-ENXIO);
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dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp,
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hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp,
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hdr->din_xfer_len);
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ret = bsg_validate_sgv4_hdr(q, hdr, &rw);
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if (ret)
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return ERR_PTR(ret);
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/*
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* map scatter-gather elements separately and string them to request
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*/
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rq = blk_get_request(q, rw, GFP_KERNEL);
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if (IS_ERR(rq))
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return rq;
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blk_rq_set_block_pc(rq);
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ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
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if (ret)
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goto out;
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if (rw == WRITE && hdr->din_xfer_len) {
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if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
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ret = -EOPNOTSUPP;
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goto out;
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}
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next_rq = blk_get_request(q, READ, GFP_KERNEL);
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if (IS_ERR(next_rq)) {
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ret = PTR_ERR(next_rq);
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next_rq = NULL;
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goto out;
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}
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rq->next_rq = next_rq;
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next_rq->cmd_type = rq->cmd_type;
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dxferp = (void __user *)(unsigned long)hdr->din_xferp;
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ret = blk_rq_map_user(q, next_rq, NULL, dxferp,
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hdr->din_xfer_len, GFP_KERNEL);
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if (ret)
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goto out;
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}
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if (hdr->dout_xfer_len) {
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dxfer_len = hdr->dout_xfer_len;
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dxferp = (void __user *)(unsigned long)hdr->dout_xferp;
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} else if (hdr->din_xfer_len) {
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dxfer_len = hdr->din_xfer_len;
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dxferp = (void __user *)(unsigned long)hdr->din_xferp;
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} else
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dxfer_len = 0;
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if (dxfer_len) {
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ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len,
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GFP_KERNEL);
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if (ret)
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goto out;
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}
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rq->sense = sense;
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rq->sense_len = 0;
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return rq;
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out:
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if (rq->cmd != rq->__cmd)
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kfree(rq->cmd);
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blk_put_request(rq);
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if (next_rq) {
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blk_rq_unmap_user(next_rq->bio);
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blk_put_request(next_rq);
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}
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return ERR_PTR(ret);
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}
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/*
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* async completion call-back from the block layer, when scsi/ide/whatever
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* calls end_that_request_last() on a request
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*/
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static void bsg_rq_end_io(struct request *rq, int uptodate)
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{
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struct bsg_command *bc = rq->end_io_data;
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struct bsg_device *bd = bc->bd;
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unsigned long flags;
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dprintk("%s: finished rq %p bc %p, bio %p stat %d\n",
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bd->name, rq, bc, bc->bio, uptodate);
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bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration);
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spin_lock_irqsave(&bd->lock, flags);
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list_move_tail(&bc->list, &bd->done_list);
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bd->done_cmds++;
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spin_unlock_irqrestore(&bd->lock, flags);
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wake_up(&bd->wq_done);
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}
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/*
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* do final setup of a 'bc' and submit the matching 'rq' to the block
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* layer for io
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*/
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static void bsg_add_command(struct bsg_device *bd, struct request_queue *q,
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struct bsg_command *bc, struct request *rq)
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{
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int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL));
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/*
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* add bc command to busy queue and submit rq for io
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*/
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bc->rq = rq;
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bc->bio = rq->bio;
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if (rq->next_rq)
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bc->bidi_bio = rq->next_rq->bio;
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bc->hdr.duration = jiffies;
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spin_lock_irq(&bd->lock);
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list_add_tail(&bc->list, &bd->busy_list);
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spin_unlock_irq(&bd->lock);
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dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc);
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rq->end_io_data = bc;
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blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io);
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}
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static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd)
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{
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struct bsg_command *bc = NULL;
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spin_lock_irq(&bd->lock);
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if (bd->done_cmds) {
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bc = list_first_entry(&bd->done_list, struct bsg_command, list);
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list_del(&bc->list);
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bd->done_cmds--;
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}
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spin_unlock_irq(&bd->lock);
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return bc;
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}
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/*
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* Get a finished command from the done list
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*/
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static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
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{
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struct bsg_command *bc;
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int ret;
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do {
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bc = bsg_next_done_cmd(bd);
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if (bc)
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break;
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if (!test_bit(BSG_F_BLOCK, &bd->flags)) {
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bc = ERR_PTR(-EAGAIN);
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break;
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}
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ret = wait_event_interruptible(bd->wq_done, bd->done_cmds);
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if (ret) {
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bc = ERR_PTR(-ERESTARTSYS);
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break;
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}
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} while (1);
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dprintk("%s: returning done %p\n", bd->name, bc);
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return bc;
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}
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static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
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struct bio *bio, struct bio *bidi_bio)
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{
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int ret = 0;
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dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors);
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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 = rq->errors & 0xff;
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hdr->transport_status = host_byte(rq->errors);
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hdr->driver_status = driver_byte(rq->errors);
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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 (rq->sense_len && hdr->response) {
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int len = min_t(unsigned int, hdr->max_response_len,
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rq->sense_len);
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ret = copy_to_user((void __user *)(unsigned long)hdr->response,
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rq->sense, len);
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if (!ret)
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hdr->response_len = len;
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else
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ret = -EFAULT;
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}
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if (rq->next_rq) {
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hdr->dout_resid = rq->resid_len;
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hdr->din_resid = rq->next_rq->resid_len;
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blk_rq_unmap_user(bidi_bio);
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blk_put_request(rq->next_rq);
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} else if (rq_data_dir(rq) == READ)
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hdr->din_resid = rq->resid_len;
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else
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hdr->dout_resid = rq->resid_len;
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|
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/*
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* If the request generated a negative error number, return it
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* (providing we aren't already returning an error); if it's
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* just a protocol response (i.e. non negative), that gets
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* processed above.
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*/
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if (!ret && rq->errors < 0)
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ret = rq->errors;
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|
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blk_rq_unmap_user(bio);
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if (rq->cmd != rq->__cmd)
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kfree(rq->cmd);
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blk_put_request(rq);
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|
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return ret;
|
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}
|
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|
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static bool bsg_complete(struct bsg_device *bd)
|
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{
|
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bool ret = false;
|
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bool spin;
|
|
|
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do {
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spin_lock_irq(&bd->lock);
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|
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BUG_ON(bd->done_cmds > bd->queued_cmds);
|
|
|
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/*
|
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* All commands consumed.
|
|
*/
|
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if (bd->done_cmds == bd->queued_cmds)
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ret = true;
|
|
|
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spin = !test_bit(BSG_F_BLOCK, &bd->flags);
|
|
|
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spin_unlock_irq(&bd->lock);
|
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} while (!ret && spin);
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|
|
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return ret;
|
|
}
|
|
|
|
static int bsg_complete_all_commands(struct bsg_device *bd)
|
|
{
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struct bsg_command *bc;
|
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int ret, tret;
|
|
|
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dprintk("%s: entered\n", bd->name);
|
|
|
|
/*
|
|
* wait for all commands to complete
|
|
*/
|
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io_wait_event(bd->wq_done, bsg_complete(bd));
|
|
|
|
/*
|
|
* discard done commands
|
|
*/
|
|
ret = 0;
|
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do {
|
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spin_lock_irq(&bd->lock);
|
|
if (!bd->queued_cmds) {
|
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spin_unlock_irq(&bd->lock);
|
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break;
|
|
}
|
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spin_unlock_irq(&bd->lock);
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|
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bc = bsg_get_done_cmd(bd);
|
|
if (IS_ERR(bc))
|
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break;
|
|
|
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tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
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bc->bidi_bio);
|
|
if (!ret)
|
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ret = tret;
|
|
|
|
bsg_free_command(bc);
|
|
} while (1);
|
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|
|
return ret;
|
|
}
|
|
|
|
static int
|
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__bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
|
|
const struct iovec *iov, ssize_t *bytes_read)
|
|
{
|
|
struct bsg_command *bc;
|
|
int nr_commands, ret;
|
|
|
|
if (count % sizeof(struct sg_io_v4))
|
|
return -EINVAL;
|
|
|
|
ret = 0;
|
|
nr_commands = count / sizeof(struct sg_io_v4);
|
|
while (nr_commands) {
|
|
bc = bsg_get_done_cmd(bd);
|
|
if (IS_ERR(bc)) {
|
|
ret = PTR_ERR(bc);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* this is the only case where we need to copy data back
|
|
* after completing the request. so do that here,
|
|
* bsg_complete_work() cannot do that for us
|
|
*/
|
|
ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
|
|
bc->bidi_bio);
|
|
|
|
if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr)))
|
|
ret = -EFAULT;
|
|
|
|
bsg_free_command(bc);
|
|
|
|
if (ret)
|
|
break;
|
|
|
|
buf += sizeof(struct sg_io_v4);
|
|
*bytes_read += sizeof(struct sg_io_v4);
|
|
nr_commands--;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
|
|
{
|
|
if (file->f_flags & O_NONBLOCK)
|
|
clear_bit(BSG_F_BLOCK, &bd->flags);
|
|
else
|
|
set_bit(BSG_F_BLOCK, &bd->flags);
|
|
}
|
|
|
|
/*
|
|
* Check if the error is a "real" error that we should return.
|
|
*/
|
|
static inline int err_block_err(int ret)
|
|
{
|
|
if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t
|
|
bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
|
|
{
|
|
struct bsg_device *bd = file->private_data;
|
|
int ret;
|
|
ssize_t bytes_read;
|
|
|
|
dprintk("%s: read %Zd bytes\n", bd->name, count);
|
|
|
|
bsg_set_block(bd, file);
|
|
|
|
bytes_read = 0;
|
|
ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
|
|
*ppos = bytes_read;
|
|
|
|
if (!bytes_read || err_block_err(ret))
|
|
bytes_read = ret;
|
|
|
|
return bytes_read;
|
|
}
|
|
|
|
static int __bsg_write(struct bsg_device *bd, const char __user *buf,
|
|
size_t count, ssize_t *bytes_written,
|
|
fmode_t has_write_perm)
|
|
{
|
|
struct bsg_command *bc;
|
|
struct request *rq;
|
|
int ret, nr_commands;
|
|
|
|
if (count % sizeof(struct sg_io_v4))
|
|
return -EINVAL;
|
|
|
|
nr_commands = count / sizeof(struct sg_io_v4);
|
|
rq = NULL;
|
|
bc = NULL;
|
|
ret = 0;
|
|
while (nr_commands) {
|
|
struct request_queue *q = bd->queue;
|
|
|
|
bc = bsg_alloc_command(bd);
|
|
if (IS_ERR(bc)) {
|
|
ret = PTR_ERR(bc);
|
|
bc = NULL;
|
|
break;
|
|
}
|
|
|
|
if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* get a request, fill in the blanks, and add to request queue
|
|
*/
|
|
rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm, bc->sense);
|
|
if (IS_ERR(rq)) {
|
|
ret = PTR_ERR(rq);
|
|
rq = NULL;
|
|
break;
|
|
}
|
|
|
|
bsg_add_command(bd, q, bc, rq);
|
|
bc = NULL;
|
|
rq = NULL;
|
|
nr_commands--;
|
|
buf += sizeof(struct sg_io_v4);
|
|
*bytes_written += sizeof(struct sg_io_v4);
|
|
}
|
|
|
|
if (bc)
|
|
bsg_free_command(bc);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t
|
|
bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
|
|
{
|
|
struct bsg_device *bd = file->private_data;
|
|
ssize_t bytes_written;
|
|
int ret;
|
|
|
|
dprintk("%s: write %Zd bytes\n", bd->name, count);
|
|
|
|
bsg_set_block(bd, file);
|
|
|
|
bytes_written = 0;
|
|
ret = __bsg_write(bd, buf, count, &bytes_written,
|
|
file->f_mode & FMODE_WRITE);
|
|
|
|
*ppos = bytes_written;
|
|
|
|
/*
|
|
* return bytes written on non-fatal errors
|
|
*/
|
|
if (!bytes_written || err_block_err(ret))
|
|
bytes_written = ret;
|
|
|
|
dprintk("%s: returning %Zd\n", bd->name, bytes_written);
|
|
return bytes_written;
|
|
}
|
|
|
|
static struct bsg_device *bsg_alloc_device(void)
|
|
{
|
|
struct bsg_device *bd;
|
|
|
|
bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
|
|
if (unlikely(!bd))
|
|
return NULL;
|
|
|
|
spin_lock_init(&bd->lock);
|
|
|
|
bd->max_queue = BSG_DEFAULT_CMDS;
|
|
|
|
INIT_LIST_HEAD(&bd->busy_list);
|
|
INIT_LIST_HEAD(&bd->done_list);
|
|
INIT_HLIST_NODE(&bd->dev_list);
|
|
|
|
init_waitqueue_head(&bd->wq_free);
|
|
init_waitqueue_head(&bd->wq_done);
|
|
return bd;
|
|
}
|
|
|
|
static void bsg_kref_release_function(struct kref *kref)
|
|
{
|
|
struct bsg_class_device *bcd =
|
|
container_of(kref, struct bsg_class_device, ref);
|
|
struct device *parent = bcd->parent;
|
|
|
|
if (bcd->release)
|
|
bcd->release(bcd->parent);
|
|
|
|
put_device(parent);
|
|
}
|
|
|
|
static int bsg_put_device(struct bsg_device *bd)
|
|
{
|
|
int ret = 0, do_free;
|
|
struct request_queue *q = bd->queue;
|
|
|
|
mutex_lock(&bsg_mutex);
|
|
|
|
do_free = atomic_dec_and_test(&bd->ref_count);
|
|
if (!do_free) {
|
|
mutex_unlock(&bsg_mutex);
|
|
goto out;
|
|
}
|
|
|
|
hlist_del(&bd->dev_list);
|
|
mutex_unlock(&bsg_mutex);
|
|
|
|
dprintk("%s: tearing down\n", bd->name);
|
|
|
|
/*
|
|
* close can always block
|
|
*/
|
|
set_bit(BSG_F_BLOCK, &bd->flags);
|
|
|
|
/*
|
|
* correct error detection baddies here again. it's the responsibility
|
|
* of the app to properly reap commands before close() if it wants
|
|
* fool-proof error detection
|
|
*/
|
|
ret = bsg_complete_all_commands(bd);
|
|
|
|
kfree(bd);
|
|
out:
|
|
kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
|
|
if (do_free)
|
|
blk_put_queue(q);
|
|
return ret;
|
|
}
|
|
|
|
static struct bsg_device *bsg_add_device(struct inode *inode,
|
|
struct request_queue *rq,
|
|
struct file *file)
|
|
{
|
|
struct bsg_device *bd;
|
|
#ifdef BSG_DEBUG
|
|
unsigned char buf[32];
|
|
#endif
|
|
if (!blk_get_queue(rq))
|
|
return ERR_PTR(-ENXIO);
|
|
|
|
bd = bsg_alloc_device();
|
|
if (!bd) {
|
|
blk_put_queue(rq);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
bd->queue = rq;
|
|
|
|
bsg_set_block(bd, file);
|
|
|
|
atomic_set(&bd->ref_count, 1);
|
|
mutex_lock(&bsg_mutex);
|
|
hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode)));
|
|
|
|
strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1);
|
|
dprintk("bound to <%s>, max queue %d\n",
|
|
format_dev_t(buf, inode->i_rdev), bd->max_queue);
|
|
|
|
mutex_unlock(&bsg_mutex);
|
|
return bd;
|
|
}
|
|
|
|
static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
|
|
{
|
|
struct bsg_device *bd;
|
|
|
|
mutex_lock(&bsg_mutex);
|
|
|
|
hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
|
|
if (bd->queue == q) {
|
|
atomic_inc(&bd->ref_count);
|
|
goto found;
|
|
}
|
|
}
|
|
bd = NULL;
|
|
found:
|
|
mutex_unlock(&bsg_mutex);
|
|
return bd;
|
|
}
|
|
|
|
static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
|
|
{
|
|
struct bsg_device *bd;
|
|
struct bsg_class_device *bcd;
|
|
|
|
/*
|
|
* find the class device
|
|
*/
|
|
mutex_lock(&bsg_mutex);
|
|
bcd = idr_find(&bsg_minor_idr, iminor(inode));
|
|
if (bcd)
|
|
kref_get(&bcd->ref);
|
|
mutex_unlock(&bsg_mutex);
|
|
|
|
if (!bcd)
|
|
return ERR_PTR(-ENODEV);
|
|
|
|
bd = __bsg_get_device(iminor(inode), bcd->queue);
|
|
if (bd)
|
|
return bd;
|
|
|
|
bd = bsg_add_device(inode, bcd->queue, file);
|
|
if (IS_ERR(bd))
|
|
kref_put(&bcd->ref, bsg_kref_release_function);
|
|
|
|
return bd;
|
|
}
|
|
|
|
static int bsg_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct bsg_device *bd;
|
|
|
|
bd = bsg_get_device(inode, file);
|
|
|
|
if (IS_ERR(bd))
|
|
return PTR_ERR(bd);
|
|
|
|
file->private_data = bd;
|
|
return 0;
|
|
}
|
|
|
|
static int bsg_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct bsg_device *bd = file->private_data;
|
|
|
|
file->private_data = NULL;
|
|
return bsg_put_device(bd);
|
|
}
|
|
|
|
static unsigned int bsg_poll(struct file *file, poll_table *wait)
|
|
{
|
|
struct bsg_device *bd = file->private_data;
|
|
unsigned int mask = 0;
|
|
|
|
poll_wait(file, &bd->wq_done, wait);
|
|
poll_wait(file, &bd->wq_free, wait);
|
|
|
|
spin_lock_irq(&bd->lock);
|
|
if (!list_empty(&bd->done_list))
|
|
mask |= POLLIN | POLLRDNORM;
|
|
if (bd->queued_cmds < bd->max_queue)
|
|
mask |= POLLOUT;
|
|
spin_unlock_irq(&bd->lock);
|
|
|
|
return mask;
|
|
}
|
|
|
|
static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct bsg_device *bd = file->private_data;
|
|
int __user *uarg = (int __user *) arg;
|
|
int ret;
|
|
|
|
switch (cmd) {
|
|
/*
|
|
* our own ioctls
|
|
*/
|
|
case SG_GET_COMMAND_Q:
|
|
return put_user(bd->max_queue, uarg);
|
|
case SG_SET_COMMAND_Q: {
|
|
int queue;
|
|
|
|
if (get_user(queue, uarg))
|
|
return -EFAULT;
|
|
if (queue < 1)
|
|
return -EINVAL;
|
|
|
|
spin_lock_irq(&bd->lock);
|
|
bd->max_queue = queue;
|
|
spin_unlock_irq(&bd->lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* SCSI/sg ioctls
|
|
*/
|
|
case SG_GET_VERSION_NUM:
|
|
case SCSI_IOCTL_GET_IDLUN:
|
|
case SCSI_IOCTL_GET_BUS_NUMBER:
|
|
case SG_SET_TIMEOUT:
|
|
case SG_GET_TIMEOUT:
|
|
case SG_GET_RESERVED_SIZE:
|
|
case SG_SET_RESERVED_SIZE:
|
|
case SG_EMULATED_HOST:
|
|
case SCSI_IOCTL_SEND_COMMAND: {
|
|
void __user *uarg = (void __user *) arg;
|
|
return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
|
|
}
|
|
case SG_IO: {
|
|
struct request *rq;
|
|
struct bio *bio, *bidi_bio = NULL;
|
|
struct sg_io_v4 hdr;
|
|
int at_head;
|
|
u8 sense[SCSI_SENSE_BUFFERSIZE];
|
|
|
|
if (copy_from_user(&hdr, uarg, sizeof(hdr)))
|
|
return -EFAULT;
|
|
|
|
rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE, sense);
|
|
if (IS_ERR(rq))
|
|
return PTR_ERR(rq);
|
|
|
|
bio = rq->bio;
|
|
if (rq->next_rq)
|
|
bidi_bio = rq->next_rq->bio;
|
|
|
|
at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
|
|
blk_execute_rq(bd->queue, NULL, rq, at_head);
|
|
ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
|
|
|
|
if (copy_to_user(uarg, &hdr, sizeof(hdr)))
|
|
return -EFAULT;
|
|
|
|
return ret;
|
|
}
|
|
/*
|
|
* block device ioctls
|
|
*/
|
|
default:
|
|
#if 0
|
|
return ioctl_by_bdev(bd->bdev, cmd, arg);
|
|
#else
|
|
return -ENOTTY;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
static const struct file_operations bsg_fops = {
|
|
.read = bsg_read,
|
|
.write = bsg_write,
|
|
.poll = bsg_poll,
|
|
.open = bsg_open,
|
|
.release = bsg_release,
|
|
.unlocked_ioctl = bsg_ioctl,
|
|
.owner = THIS_MODULE,
|
|
.llseek = default_llseek,
|
|
};
|
|
|
|
void bsg_unregister_queue(struct request_queue *q)
|
|
{
|
|
struct bsg_class_device *bcd = &q->bsg_dev;
|
|
|
|
if (!bcd->class_dev)
|
|
return;
|
|
|
|
mutex_lock(&bsg_mutex);
|
|
idr_remove(&bsg_minor_idr, bcd->minor);
|
|
if (q->kobj.sd)
|
|
sysfs_remove_link(&q->kobj, "bsg");
|
|
device_unregister(bcd->class_dev);
|
|
bcd->class_dev = NULL;
|
|
kref_put(&bcd->ref, bsg_kref_release_function);
|
|
mutex_unlock(&bsg_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bsg_unregister_queue);
|
|
|
|
int bsg_register_queue(struct request_queue *q, struct device *parent,
|
|
const char *name, void (*release)(struct device *))
|
|
{
|
|
struct bsg_class_device *bcd;
|
|
dev_t dev;
|
|
int ret;
|
|
struct device *class_dev = NULL;
|
|
const char *devname;
|
|
|
|
if (name)
|
|
devname = name;
|
|
else
|
|
devname = dev_name(parent);
|
|
|
|
/*
|
|
* we need a proper transport to send commands, not a stacked device
|
|
*/
|
|
if (!queue_is_rq_based(q))
|
|
return 0;
|
|
|
|
bcd = &q->bsg_dev;
|
|
memset(bcd, 0, sizeof(*bcd));
|
|
|
|
mutex_lock(&bsg_mutex);
|
|
|
|
ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
|
|
if (ret < 0) {
|
|
if (ret == -ENOSPC) {
|
|
printk(KERN_ERR "bsg: too many bsg devices\n");
|
|
ret = -EINVAL;
|
|
}
|
|
goto unlock;
|
|
}
|
|
|
|
bcd->minor = ret;
|
|
bcd->queue = q;
|
|
bcd->parent = get_device(parent);
|
|
bcd->release = release;
|
|
kref_init(&bcd->ref);
|
|
dev = MKDEV(bsg_major, bcd->minor);
|
|
class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
|
|
if (IS_ERR(class_dev)) {
|
|
ret = PTR_ERR(class_dev);
|
|
goto put_dev;
|
|
}
|
|
bcd->class_dev = class_dev;
|
|
|
|
if (q->kobj.sd) {
|
|
ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg");
|
|
if (ret)
|
|
goto unregister_class_dev;
|
|
}
|
|
|
|
mutex_unlock(&bsg_mutex);
|
|
return 0;
|
|
|
|
unregister_class_dev:
|
|
device_unregister(class_dev);
|
|
put_dev:
|
|
put_device(parent);
|
|
idr_remove(&bsg_minor_idr, bcd->minor);
|
|
unlock:
|
|
mutex_unlock(&bsg_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bsg_register_queue);
|
|
|
|
static struct cdev bsg_cdev;
|
|
|
|
static char *bsg_devnode(struct device *dev, umode_t *mode)
|
|
{
|
|
return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev));
|
|
}
|
|
|
|
static int __init bsg_init(void)
|
|
{
|
|
int ret, i;
|
|
dev_t devid;
|
|
|
|
bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
|
|
sizeof(struct bsg_command), 0, 0, NULL);
|
|
if (!bsg_cmd_cachep) {
|
|
printk(KERN_ERR "bsg: failed creating slab cache\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++)
|
|
INIT_HLIST_HEAD(&bsg_device_list[i]);
|
|
|
|
bsg_class = class_create(THIS_MODULE, "bsg");
|
|
if (IS_ERR(bsg_class)) {
|
|
ret = PTR_ERR(bsg_class);
|
|
goto destroy_kmemcache;
|
|
}
|
|
bsg_class->devnode = bsg_devnode;
|
|
|
|
ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg");
|
|
if (ret)
|
|
goto destroy_bsg_class;
|
|
|
|
bsg_major = MAJOR(devid);
|
|
|
|
cdev_init(&bsg_cdev, &bsg_fops);
|
|
ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS);
|
|
if (ret)
|
|
goto unregister_chrdev;
|
|
|
|
printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
|
|
" loaded (major %d)\n", bsg_major);
|
|
return 0;
|
|
unregister_chrdev:
|
|
unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
|
|
destroy_bsg_class:
|
|
class_destroy(bsg_class);
|
|
destroy_kmemcache:
|
|
kmem_cache_destroy(bsg_cmd_cachep);
|
|
return ret;
|
|
}
|
|
|
|
MODULE_AUTHOR("Jens Axboe");
|
|
MODULE_DESCRIPTION(BSG_DESCRIPTION);
|
|
MODULE_LICENSE("GPL");
|
|
|
|
device_initcall(bsg_init);
|