Commit 74e6464a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarChristian Brauner <brauner@kernel.org>
Acked-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-4-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ae5f855e

block/bdev.c

+13 −14
Original line number Diff line number Diff line
@@ -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 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder) 
		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 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder) 


	/* 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