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authorTetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>2021-09-07 19:18:00 +0900
committerJens Axboe <axboe@kernel.dk>2021-10-17 06:51:19 -0600
commitf7bf35862477d6d4f8a9746c645a4380de984700 (patch)
treee95a4fb202a0a1eec7c7bdfa96af425569b14ddc /drivers/block/brd.c
parentc41108049d143304faf06852c7181262b7b0d242 (diff)
brd: reduce the brd_devices_mutex scope
As with commit 8b52d8be86d72308 ("loop: reorder loop_exit"), unregister_blkdev() needs to be called first in order to avoid calling brd_alloc() from brd_probe() after brd_del_one() from brd_exit(). Then, we can avoid holding global mutex during add_disk()/del_gendisk() as with commit 1c500ad706383f1a ("loop: reduce the loop_ctl_mutex scope"). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/e205f13d-18ff-a49c-0988-7de6ea5ff823@i-love.sakura.ne.jp Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/brd.c')
-rw-r--r--drivers/block/brd.c44
1 files changed, 22 insertions, 22 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 58ec167aa018..530b31240203 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -373,10 +373,22 @@ static int brd_alloc(int i)
struct gendisk *disk;
char buf[DISK_NAME_LEN];
+ mutex_lock(&brd_devices_mutex);
+ list_for_each_entry(brd, &brd_devices, brd_list) {
+ if (brd->brd_number == i) {
+ mutex_unlock(&brd_devices_mutex);
+ return -EEXIST;
+ }
+ }
brd = kzalloc(sizeof(*brd), GFP_KERNEL);
- if (!brd)
+ if (!brd) {
+ mutex_unlock(&brd_devices_mutex);
return -ENOMEM;
+ }
brd->brd_number = i;
+ list_add_tail(&brd->brd_list, &brd_devices);
+ mutex_unlock(&brd_devices_mutex);
+
spin_lock_init(&brd->brd_lock);
INIT_RADIX_TREE(&brd->brd_pages, GFP_ATOMIC);
@@ -411,37 +423,30 @@ static int brd_alloc(int i)
blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
add_disk(disk);
- list_add_tail(&brd->brd_list, &brd_devices);
return 0;
out_free_dev:
+ mutex_lock(&brd_devices_mutex);
+ list_del(&brd->brd_list);
+ mutex_unlock(&brd_devices_mutex);
kfree(brd);
return -ENOMEM;
}
static void brd_probe(dev_t dev)
{
- int i = MINOR(dev) / max_part;
- struct brd_device *brd;
-
- mutex_lock(&brd_devices_mutex);
- list_for_each_entry(brd, &brd_devices, brd_list) {
- if (brd->brd_number == i)
- goto out_unlock;
- }
-
- brd_alloc(i);
-out_unlock:
- mutex_unlock(&brd_devices_mutex);
+ brd_alloc(MINOR(dev) / max_part);
}
static void brd_del_one(struct brd_device *brd)
{
- list_del(&brd->brd_list);
del_gendisk(brd->brd_disk);
blk_cleanup_disk(brd->brd_disk);
brd_free_pages(brd);
+ mutex_lock(&brd_devices_mutex);
+ list_del(&brd->brd_list);
+ mutex_unlock(&brd_devices_mutex);
kfree(brd);
}
@@ -491,25 +496,21 @@ static int __init brd_init(void)
brd_debugfs_dir = debugfs_create_dir("ramdisk_pages", NULL);
- mutex_lock(&brd_devices_mutex);
for (i = 0; i < rd_nr; i++) {
err = brd_alloc(i);
if (err)
goto out_free;
}
- mutex_unlock(&brd_devices_mutex);
-
pr_info("brd: module loaded\n");
return 0;
out_free:
+ unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
debugfs_remove_recursive(brd_debugfs_dir);
list_for_each_entry_safe(brd, next, &brd_devices, brd_list)
brd_del_one(brd);
- mutex_unlock(&brd_devices_mutex);
- unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
pr_info("brd: module NOT loaded !!!\n");
return err;
@@ -519,13 +520,12 @@ static void __exit brd_exit(void)
{
struct brd_device *brd, *next;
+ unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
debugfs_remove_recursive(brd_debugfs_dir);
list_for_each_entry_safe(brd, next, &brd_devices, brd_list)
brd_del_one(brd);
- unregister_blkdev(RAMDISK_MAJOR, "ramdisk");
-
pr_info("brd: module unloaded\n");
}