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block: turn bdev_lock into a mutex 

There is no reason for this lock to spin, and being able to sleep under
it will come in handy soon.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2023-06-01 11:44:46 +02:00 committed by Jens Axboe
parent ae5f855ead
commit 74e6464a98
1 changed files with 13 additions and 14 deletions
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27
block/bdev.c
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@ -308,7 +308,7 @@ EXPORT_SYMBOL(thaw_bdev);
* pseudo-fs
*/
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
static __cacheline_aligned_in_smp DEFINE_MUTEX(bdev_lock);
static struct kmem_cache * bdev_cachep __read_mostly;
static struct inode *bdev_alloc_inode(struct super_block *sb)
@ -467,9 +467,6 @@ long nr_blockdev_pages(void)
*
* Test whether @bdev can be claimed by @holder.
*
* CONTEXT:
* spin_lock(&bdev_lock).
*
* RETURNS:
* %true if @bdev can be claimed, %false otherwise.
*/
@ -477,6 +474,8 @@ static bool bd_may_claim(struct block_device *bdev, void *holder)
{
struct block_device *whole = bdev_whole(bdev);
lockdep_assert_held(&bdev_lock);
if (bdev->bd_holder) {
/*
* The same holder can always re-claim.
@ -515,10 +514,10 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder)
if (WARN_ON_ONCE(!holder))
return -EINVAL;
retry:
spin_lock(&bdev_lock);
mutex_lock(&bdev_lock);
/* if someone else claimed, fail */
if (!bd_may_claim(bdev, holder)) {
spin_unlock(&bdev_lock);
mutex_unlock(&bdev_lock);
return -EBUSY;
}
@ -528,7 +527,7 @@ retry:
DEFINE_WAIT(wait);
prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&bdev_lock);
mutex_unlock(&bdev_lock);
schedule();
finish_wait(wq, &wait);
goto retry;
@ -536,7 +535,7 @@ retry:
/* yay, all mine */
whole->bd_claiming = holder;
spin_unlock(&bdev_lock);
mutex_unlock(&bdev_lock);
return 0;
}
EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
@ -562,7 +561,7 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder)
{
struct block_device *whole = bdev_whole(bdev);
spin_lock(&bdev_lock);
mutex_lock(&bdev_lock);
BUG_ON(!bd_may_claim(bdev, holder));
/*
* Note that for a whole device bd_holders will be incremented twice,
@ -573,7 +572,7 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder)
bdev->bd_holders++;
bdev->bd_holder = holder;
bd_clear_claiming(whole, holder);
spin_unlock(&bdev_lock);
mutex_unlock(&bdev_lock);
}
/**
@ -587,9 +586,9 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder)
*/
void bd_abort_claiming(struct block_device *bdev, void *holder)
{
spin_lock(&bdev_lock);
mutex_lock(&bdev_lock);
bd_clear_claiming(bdev_whole(bdev), holder);
spin_unlock(&bdev_lock);
mutex_unlock(&bdev_lock);
}
EXPORT_SYMBOL(bd_abort_claiming);
@ -602,7 +601,7 @@ static void bd_end_claim(struct block_device *bdev)
* Release a claim on the device. The holder fields are protected with
* bdev_lock. open_mutex is used to synchronize disk_holder unlinking.
*/
spin_lock(&bdev_lock);
mutex_lock(&bdev_lock);
WARN_ON_ONCE(--bdev->bd_holders < 0);
WARN_ON_ONCE(--whole->bd_holders < 0);
if (!bdev->bd_holders) {
@ -612,7 +611,7 @@ static void bd_end_claim(struct block_device *bdev)
}
if (!whole->bd_holders)
whole->bd_holder = NULL;
spin_unlock(&bdev_lock);
mutex_unlock(&bdev_lock);
/*
* If this was the last claim, remove holder link and unblock evpoll if