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authorChristoph Hellwig <hch@lst.de>2020-11-26 11:23:26 +0300
committerJens Axboe <axboe@kernel.dk>2020-12-02 00:53:39 +0300
commit22ae8ce8b89241c94ac00c237752c0ffa37ba5ae (patch)
treeaf6d4dfd72e76789c25c64cd1765f037d91f6b72 /block/blk-cgroup.c
parent4e7b5671c6a883d94b5428e1a9c141bbd56cb2a6 (diff)
downloadlinux-22ae8ce8b89241c94ac00c237752c0ffa37ba5ae.tar.xz
block: simplify bdev/disk lookup in blkdev_get
To simplify block device lookup and a few other upcoming areas, make sure that we always have a struct block_device available for each disk and each partition, and only find existing block devices in bdget. The only downside of this is that each device and partition uses a little more memory. The upside will be that a lot of code can be simplified. With that all we need to look up the block device is to lookup the inode and do a few sanity checks on the gendisk, instead of the separate lookup for the gendisk. For blk-cgroup which wants to access a gendisk without opening it, a new blkdev_{get,put}_no_open low-level interface is added to replace the previous get_gendisk use. Note that the change to look up block device directly instead of the two step lookup using struct gendisk causes a subtile change in behavior: accessing a non-existing partition on an existing block device can now cause a call to request_module. That call is harmless, and in practice no recent system will access these nodes as they aren't created by udev and static /dev/ setups are unusual. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-cgroup.c')
-rw-r--r--block/blk-cgroup.c42
1 files changed, 21 insertions, 21 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index c68bdf58c9a6..ad02289a4f7f 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -556,22 +556,22 @@ static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg,
}
/**
- * blkg_conf_prep - parse and prepare for per-blkg config update
+ * blkcg_conf_open_bdev - parse and open bdev for per-blkg config update
* @inputp: input string pointer
*
* Parse the device node prefix part, MAJ:MIN, of per-blkg config update
- * from @input and get and return the matching gendisk. *@inputp is
+ * from @input and get and return the matching bdev. *@inputp is
* updated to point past the device node prefix. Returns an ERR_PTR()
* value on error.
*
* Use this function iff blkg_conf_prep() can't be used for some reason.
*/
-struct gendisk *blkcg_conf_get_disk(char **inputp)
+struct block_device *blkcg_conf_open_bdev(char **inputp)
{
char *input = *inputp;
unsigned int major, minor;
- struct gendisk *disk;
- int key_len, part;
+ struct block_device *bdev;
+ int key_len;
if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2)
return ERR_PTR(-EINVAL);
@@ -581,16 +581,16 @@ struct gendisk *blkcg_conf_get_disk(char **inputp)
return ERR_PTR(-EINVAL);
input = skip_spaces(input);
- disk = get_gendisk(MKDEV(major, minor), &part);
- if (!disk)
+ bdev = blkdev_get_no_open(MKDEV(major, minor));
+ if (!bdev)
return ERR_PTR(-ENODEV);
- if (part) {
- put_disk_and_module(disk);
+ if (bdev_is_partition(bdev)) {
+ blkdev_put_no_open(bdev);
return ERR_PTR(-ENODEV);
}
*inputp = input;
- return disk;
+ return bdev;
}
/**
@@ -607,18 +607,18 @@ struct gendisk *blkcg_conf_get_disk(char **inputp)
*/
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
char *input, struct blkg_conf_ctx *ctx)
- __acquires(rcu) __acquires(&disk->queue->queue_lock)
+ __acquires(rcu) __acquires(&bdev->bd_disk->queue->queue_lock)
{
- struct gendisk *disk;
+ struct block_device *bdev;
struct request_queue *q;
struct blkcg_gq *blkg;
int ret;
- disk = blkcg_conf_get_disk(&input);
- if (IS_ERR(disk))
- return PTR_ERR(disk);
+ bdev = blkcg_conf_open_bdev(&input);
+ if (IS_ERR(bdev))
+ return PTR_ERR(bdev);
- q = disk->queue;
+ q = bdev->bd_disk->queue;
rcu_read_lock();
spin_lock_irq(&q->queue_lock);
@@ -689,7 +689,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
goto success;
}
success:
- ctx->disk = disk;
+ ctx->bdev = bdev;
ctx->blkg = blkg;
ctx->body = input;
return 0;
@@ -700,7 +700,7 @@ fail_unlock:
spin_unlock_irq(&q->queue_lock);
rcu_read_unlock();
fail:
- put_disk_and_module(disk);
+ blkdev_put_no_open(bdev);
/*
* If queue was bypassing, we should retry. Do so after a
* short msleep(). It isn't strictly necessary but queue
@@ -723,11 +723,11 @@ EXPORT_SYMBOL_GPL(blkg_conf_prep);
* with blkg_conf_prep().
*/
void blkg_conf_finish(struct blkg_conf_ctx *ctx)
- __releases(&ctx->disk->queue->queue_lock) __releases(rcu)
+ __releases(&ctx->bdev->bd_disk->queue->queue_lock) __releases(rcu)
{
- spin_unlock_irq(&ctx->disk->queue->queue_lock);
+ spin_unlock_irq(&ctx->bdev->bd_disk->queue->queue_lock);
rcu_read_unlock();
- put_disk_and_module(ctx->disk);
+ blkdev_put_no_open(ctx->bdev);
}
EXPORT_SYMBOL_GPL(blkg_conf_finish);