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>
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index bbe86d1..8e20fe4 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -3120,23 +3120,23 @@ static const match_table_t qos_tokens = {
static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
size_t nbytes, loff_t off)
{
- struct gendisk *disk;
+ struct block_device *bdev;
struct ioc *ioc;
u32 qos[NR_QOS_PARAMS];
bool enable, user;
char *p;
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);
- ioc = q_to_ioc(disk->queue);
+ ioc = q_to_ioc(bdev->bd_disk->queue);
if (!ioc) {
- ret = blk_iocost_init(disk->queue);
+ ret = blk_iocost_init(bdev->bd_disk->queue);
if (ret)
goto err;
- ioc = q_to_ioc(disk->queue);
+ ioc = q_to_ioc(bdev->bd_disk->queue);
}
spin_lock_irq(&ioc->lock);
@@ -3231,12 +3231,12 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
ioc_refresh_params(ioc, true);
spin_unlock_irq(&ioc->lock);
- put_disk_and_module(disk);
+ blkdev_put_no_open(bdev);
return nbytes;
einval:
ret = -EINVAL;
err:
- put_disk_and_module(disk);
+ blkdev_put_no_open(bdev);
return ret;
}
@@ -3287,23 +3287,23 @@ static const match_table_t i_lcoef_tokens = {
static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input,
size_t nbytes, loff_t off)
{
- struct gendisk *disk;
+ struct block_device *bdev;
struct ioc *ioc;
u64 u[NR_I_LCOEFS];
bool user;
char *p;
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);
- ioc = q_to_ioc(disk->queue);
+ ioc = q_to_ioc(bdev->bd_disk->queue);
if (!ioc) {
- ret = blk_iocost_init(disk->queue);
+ ret = blk_iocost_init(bdev->bd_disk->queue);
if (ret)
goto err;
- ioc = q_to_ioc(disk->queue);
+ ioc = q_to_ioc(bdev->bd_disk->queue);
}
spin_lock_irq(&ioc->lock);
@@ -3356,13 +3356,13 @@ static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input,
ioc_refresh_params(ioc, true);
spin_unlock_irq(&ioc->lock);
- put_disk_and_module(disk);
+ blkdev_put_no_open(bdev);
return nbytes;
einval:
ret = -EINVAL;
err:
- put_disk_and_module(disk);
+ blkdev_put_no_open(bdev);
return ret;
}
