From 5309cb38de65eddd5f7e125da750accf949f29e8 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 23 Jan 2007 16:24:41 +0100 Subject: [PATCH] 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 , changed by me to not use a mempool. Signed-off-by: Jens Axboe --- block/bsg.c | 96 ++++++++++++++++++----------------------------------- 1 file changed, 32 insertions(+), 64 deletions(-) diff --git a/block/bsg.c b/block/bsg.c index 9d77a0c72457..c56618ae54c3 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -33,8 +33,6 @@ static char bsg_version[] = "block layer sg (bsg) 0.4"; -struct bsg_command; - struct bsg_device { struct gendisk *disk; request_queue_t *queue; @@ -46,8 +44,6 @@ struct bsg_device { int minor; int queued_cmds; int done_cmds; - unsigned long *cmd_bitmap; - struct bsg_command *cmd_map; wait_queue_head_t wq_done; wait_queue_head_t wq_free; char name[BDEVNAME_SIZE]; @@ -60,14 +56,7 @@ enum { BSG_F_WRITE_PERM = 2, }; -/* - * command allocation bitmap defines - */ -#define BSG_CMDS_PAGE_ORDER (1) -#define BSG_CMDS_PER_LONG (sizeof(unsigned long) * 8) -#define BSG_CMDS_MASK (BSG_CMDS_PER_LONG - 1) -#define BSG_CMDS_BYTES (PAGE_SIZE * (1 << BSG_CMDS_PAGE_ORDER)) -#define BSG_CMDS (BSG_CMDS_BYTES / sizeof(struct bsg_command)) +#define BSG_DEFAULT_CMDS 64 #undef BSG_DEBUG @@ -94,6 +83,8 @@ static struct hlist_head bsg_device_list[BSG_LIST_SIZE]; static struct class *bsg_class; static LIST_HEAD(bsg_class_list); +static struct kmem_cache *bsg_cmd_cachep; + /* * our internal command type */ @@ -111,14 +102,12 @@ struct bsg_command { static void bsg_free_command(struct bsg_command *bc) { struct bsg_device *bd = bc->bd; - unsigned long bitnr = bc - bd->cmd_map; unsigned long flags; - dprintk("%s: command bit offset %lu\n", bd->name, bitnr); + kmem_cache_free(bsg_cmd_cachep, bc); spin_lock_irqsave(&bd->lock, flags); bd->queued_cmds--; - __clear_bit(bitnr, bd->cmd_bitmap); spin_unlock_irqrestore(&bd->lock, flags); wake_up(&bd->wq_free); @@ -127,32 +116,29 @@ static void bsg_free_command(struct bsg_command *bc) static struct bsg_command *__bsg_alloc_command(struct bsg_device *bd) { struct bsg_command *bc = NULL; - unsigned long *map; - int free_nr; spin_lock_irq(&bd->lock); if (bd->queued_cmds >= bd->max_queue) goto out; - for (free_nr = 0, map = bd->cmd_bitmap; *map == ~0UL; map++) - free_nr += BSG_CMDS_PER_LONG; - - BUG_ON(*map == ~0UL); - bd->queued_cmds++; - free_nr += ffz(*map); - __set_bit(free_nr, bd->cmd_bitmap); spin_unlock_irq(&bd->lock); - bc = bd->cmd_map + free_nr; + bc = kmem_cache_alloc(bsg_cmd_cachep, GFP_USER); + if (unlikely(!bc)) { + spin_lock_irq(&bd->lock); + goto alloc_fail; + } + memset(bc, 0, sizeof(*bc)); bc->bd = bd; INIT_LIST_HEAD(&bc->list); - dprintk("%s: returning free cmd %p (bit %d)\n", bd->name, bc, free_nr); + dprintk("%s: returning free cmd %p\n", bd->name, bc); return bc; +alloc_fail: + bd->queued_cmds--; out: - dprintk("%s: failed (depth %d)\n", bd->name, bd->queued_cmds); spin_unlock_irq(&bd->lock); return bc; } @@ -356,8 +342,8 @@ static void bsg_rq_end_io(struct request *rq, int uptodate) struct bsg_device *bd = bc->bd; unsigned long flags; - dprintk("%s: finished rq %p bc %p, bio %p offset %Zd stat %d\n", - bd->name, rq, bc, bc->bio, bc - bd->cmd_map, uptodate); + dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", + bd->name, rq, bc, bc->bio, uptodate); bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); @@ -703,21 +689,9 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) return bytes_read; } -static void bsg_free_device(struct bsg_device *bd) -{ - if (bd->cmd_map) - free_pages((unsigned long) bd->cmd_map, BSG_CMDS_PAGE_ORDER); - - kfree(bd->cmd_bitmap); - kfree(bd); -} - static struct bsg_device *bsg_alloc_device(void) { - struct bsg_command *cmd_map; - unsigned long *cmd_bitmap; struct bsg_device *bd; - int bits; bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); if (unlikely(!bd)) @@ -725,19 +699,7 @@ static struct bsg_device *bsg_alloc_device(void) spin_lock_init(&bd->lock); - bd->max_queue = BSG_CMDS; - - bits = (BSG_CMDS / BSG_CMDS_PER_LONG) + 1; - cmd_bitmap = kzalloc(bits * sizeof(unsigned long), GFP_KERNEL); - if (!cmd_bitmap) - goto out_free_bd; - bd->cmd_bitmap = cmd_bitmap; - - cmd_map = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO, - BSG_CMDS_PAGE_ORDER); - if (!cmd_map) - goto out_free_bitmap; - bd->cmd_map = cmd_map; + bd->max_queue = BSG_DEFAULT_CMDS; INIT_LIST_HEAD(&bd->busy_list); INIT_LIST_HEAD(&bd->done_list); @@ -746,12 +708,6 @@ static struct bsg_device *bsg_alloc_device(void) init_waitqueue_head(&bd->wq_free); init_waitqueue_head(&bd->wq_done); return bd; - -out_free_bitmap: - kfree(cmd_bitmap); -out_free_bd: - kfree(bd); - return NULL; } static int bsg_put_device(struct bsg_device *bd) @@ -779,7 +735,7 @@ static int bsg_put_device(struct bsg_device *bd) blk_put_queue(bd->queue); hlist_del(&bd->dev_list); - bsg_free_device(bd); + kfree(bd); out: mutex_unlock(&bsg_mutex); return ret; @@ -918,15 +874,17 @@ bsg_ioctl(struct inode *inode, struct file *file, unsigned int cmd, */ case SG_GET_COMMAND_Q: return put_user(bd->max_queue, uarg); - case SG_SET_COMMAND_Q: { + case SG_SET_COMMAND_Q: { int queue; if (get_user(queue, uarg)) return -EFAULT; - if (queue > BSG_CMDS || queue < 1) + if (queue < 1) return -EINVAL; + spin_lock_irq(&bd->lock); bd->max_queue = queue; + spin_unlock_irq(&bd->lock); return 0; } @@ -1035,15 +993,25 @@ static int __init bsg_init(void) { int ret, i; + bsg_cmd_cachep = kmem_cache_create("bsg_cmd", + sizeof(struct bsg_command), 0, 0, NULL, NULL); + if (!bsg_cmd_cachep) { + printk(KERN_ERR "bsg: failed creating slab cache\n"); + return -ENOMEM; + } + for (i = 0; i < BSG_LIST_SIZE; i++) INIT_HLIST_HEAD(&bsg_device_list[i]); bsg_class = class_create(THIS_MODULE, "bsg"); - if (IS_ERR(bsg_class)) + if (IS_ERR(bsg_class)) { + kmem_cache_destroy(bsg_cmd_cachep); return PTR_ERR(bsg_class); + } ret = register_chrdev(BSG_MAJOR, "bsg", &bsg_fops); if (ret) { + kmem_cache_destroy(bsg_cmd_cachep); class_destroy(bsg_class); return ret; } -- 2.39.5