Add queue resizing support
Just get rid of the preallocated command map, use the slab cache to get/free commands instead. Original patch from FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>, changed by me to not use a mempool. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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3862153b67
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5309cb38de
94
block/bsg.c
94
block/bsg.c
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@ -33,8 +33,6 @@
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static char bsg_version[] = "block layer sg (bsg) 0.4";
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struct bsg_command;
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struct bsg_device {
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struct gendisk *disk;
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request_queue_t *queue;
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@ -46,8 +44,6 @@ struct bsg_device {
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int minor;
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int queued_cmds;
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int done_cmds;
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unsigned long *cmd_bitmap;
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struct bsg_command *cmd_map;
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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[BDEVNAME_SIZE];
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@ -60,14 +56,7 @@ enum {
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BSG_F_WRITE_PERM = 2,
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};
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/*
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* command allocation bitmap defines
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*/
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#define BSG_CMDS_PAGE_ORDER (1)
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#define BSG_CMDS_PER_LONG (sizeof(unsigned long) * 8)
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#define BSG_CMDS_MASK (BSG_CMDS_PER_LONG - 1)
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#define BSG_CMDS_BYTES (PAGE_SIZE * (1 << BSG_CMDS_PAGE_ORDER))
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#define BSG_CMDS (BSG_CMDS_BYTES / sizeof(struct bsg_command))
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#define BSG_DEFAULT_CMDS 64
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#undef BSG_DEBUG
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@ -94,6 +83,8 @@ static struct hlist_head bsg_device_list[BSG_LIST_SIZE];
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static struct class *bsg_class;
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static LIST_HEAD(bsg_class_list);
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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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@ -111,14 +102,12 @@ struct bsg_command {
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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 bitnr = bc - bd->cmd_map;
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unsigned long flags;
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dprintk("%s: command bit offset %lu\n", bd->name, bitnr);
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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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__clear_bit(bitnr, bd->cmd_bitmap);
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spin_unlock_irqrestore(&bd->lock, flags);
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wake_up(&bd->wq_free);
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@ -127,32 +116,29 @@ static void bsg_free_command(struct bsg_command *bc)
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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 = NULL;
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unsigned long *map;
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int free_nr;
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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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for (free_nr = 0, map = bd->cmd_bitmap; *map == ~0UL; map++)
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free_nr += BSG_CMDS_PER_LONG;
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BUG_ON(*map == ~0UL);
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bd->queued_cmds++;
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free_nr += ffz(*map);
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__set_bit(free_nr, bd->cmd_bitmap);
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spin_unlock_irq(&bd->lock);
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bc = bd->cmd_map + free_nr;
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bc = kmem_cache_alloc(bsg_cmd_cachep, GFP_USER);
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if (unlikely(!bc)) {
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spin_lock_irq(&bd->lock);
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goto alloc_fail;
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}
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memset(bc, 0, sizeof(*bc));
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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 (bit %d)\n", bd->name, bc, free_nr);
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dprintk("%s: returning free cmd %p\n", bd->name, bc);
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return bc;
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alloc_fail:
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bd->queued_cmds--;
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out:
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dprintk("%s: failed (depth %d)\n", bd->name, bd->queued_cmds);
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spin_unlock_irq(&bd->lock);
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return bc;
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}
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@ -356,8 +342,8 @@ static void bsg_rq_end_io(struct request *rq, int uptodate)
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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 offset %Zd stat %d\n",
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bd->name, rq, bc, bc->bio, bc - bd->cmd_map, uptodate);
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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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@ -703,21 +689,9 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
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return bytes_read;
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}
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static void bsg_free_device(struct bsg_device *bd)
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{
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if (bd->cmd_map)
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free_pages((unsigned long) bd->cmd_map, BSG_CMDS_PAGE_ORDER);
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kfree(bd->cmd_bitmap);
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kfree(bd);
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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_command *cmd_map;
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unsigned long *cmd_bitmap;
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struct bsg_device *bd;
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int bits;
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bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL);
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if (unlikely(!bd))
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@ -725,19 +699,7 @@ static struct bsg_device *bsg_alloc_device(void)
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spin_lock_init(&bd->lock);
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bd->max_queue = BSG_CMDS;
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bits = (BSG_CMDS / BSG_CMDS_PER_LONG) + 1;
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cmd_bitmap = kzalloc(bits * sizeof(unsigned long), GFP_KERNEL);
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if (!cmd_bitmap)
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goto out_free_bd;
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bd->cmd_bitmap = cmd_bitmap;
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cmd_map = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
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BSG_CMDS_PAGE_ORDER);
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if (!cmd_map)
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goto out_free_bitmap;
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bd->cmd_map = cmd_map;
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bd->max_queue = BSG_DEFAULT_CMDS;
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INIT_LIST_HEAD(&bd->busy_list);
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INIT_LIST_HEAD(&bd->done_list);
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init_waitqueue_head(&bd->wq_free);
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init_waitqueue_head(&bd->wq_done);
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return bd;
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out_free_bitmap:
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kfree(cmd_bitmap);
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out_free_bd:
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kfree(bd);
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return NULL;
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}
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static int bsg_put_device(struct bsg_device *bd)
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@ -779,7 +735,7 @@ static int bsg_put_device(struct bsg_device *bd)
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blk_put_queue(bd->queue);
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hlist_del(&bd->dev_list);
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bsg_free_device(bd);
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kfree(bd);
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out:
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mutex_unlock(&bsg_mutex);
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return ret;
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@ -923,10 +879,12 @@ bsg_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
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if (get_user(queue, uarg))
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return -EFAULT;
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if (queue > BSG_CMDS || queue < 1)
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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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@ -1035,15 +993,25 @@ static int __init bsg_init(void)
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{
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int ret, i;
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bsg_cmd_cachep = kmem_cache_create("bsg_cmd",
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sizeof(struct bsg_command), 0, 0, NULL, NULL);
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if (!bsg_cmd_cachep) {
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printk(KERN_ERR "bsg: failed creating slab cache\n");
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return -ENOMEM;
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}
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for (i = 0; i < BSG_LIST_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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if (IS_ERR(bsg_class)) {
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kmem_cache_destroy(bsg_cmd_cachep);
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return PTR_ERR(bsg_class);
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}
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ret = register_chrdev(BSG_MAJOR, "bsg", &bsg_fops);
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if (ret) {
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kmem_cache_destroy(bsg_cmd_cachep);
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class_destroy(bsg_class);
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return ret;
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}
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