@@ -487,10 +487,10 @@ long nr_blockdev_pages(void)
* Test whether @bdev can be claimed by @holder.
*
* RETURNS:
- * %true if @bdev can be claimed, %false otherwise.
+ * %0 if @bdev can be claimed, %-EBUSY otherwise.
*/
-static bool bd_may_claim(struct block_device *bdev, void *holder,
- const struct blk_holder_ops *hops)
+static int bd_may_claim(struct block_device *bdev, void *holder,
+ const struct blk_holder_ops *hops)
{
struct block_device *whole = bdev_whole(bdev);
@@ -503,9 +503,9 @@ static bool bd_may_claim(struct block_device *bdev, void *holder,
if (bdev->bd_holder == holder) {
if (WARN_ON_ONCE(bdev->bd_holder_ops != hops))
return false;
- return true;
+ return 0;
}
- return false;
+ return -EBUSY;
}
/*
@@ -514,8 +514,8 @@ static bool bd_may_claim(struct block_device *bdev, void *holder,
*/
if (whole != bdev &&
whole->bd_holder && whole->bd_holder != bd_may_claim)
- return false;
- return true;
+ return -EBUSY;
+ return 0;
}
/**
@@ -535,43 +535,32 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder,
const struct blk_holder_ops *hops)
{
struct block_device *whole = bdev_whole(bdev);
+ int err = 0;
if (WARN_ON_ONCE(!holder))
return -EINVAL;
-retry:
- mutex_lock(&bdev_lock);
- /* if someone else claimed, fail */
- if (!bd_may_claim(bdev, holder, hops)) {
- mutex_unlock(&bdev_lock);
- return -EBUSY;
- }
- /* if claiming is already in progress, wait for it to finish */
- if (whole->bd_claiming) {
- wait_queue_head_t *wq = __var_waitqueue(&whole->bd_claiming);
- DEFINE_WAIT(wait);
-
- prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
- mutex_unlock(&bdev_lock);
- schedule();
- finish_wait(wq, &wait);
- goto retry;
- }
+ mutex_lock(&bdev_lock);
+ wait_var_event_mutex(&whole->bd_claiming,
+ (err = bd_may_claim(bdev, holder, hops)) != 0 ||
+ whole->bd_claiming == NULL,
+ &bdev_lock);
- /* yay, all mine */
- whole->bd_claiming = holder;
+ /* if someone else claimed, fail */
+ if (!err)
+ /* yay, all mine */
+ whole->bd_claiming = holder;
mutex_unlock(&bdev_lock);
- return 0;
+ return err;
}
EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
static void bd_clear_claiming(struct block_device *whole, void *holder)
{
- lockdep_assert_held(&bdev_lock);
/* tell others that we're done */
BUG_ON(whole->bd_claiming != holder);
whole->bd_claiming = NULL;
- wake_up_var(&whole->bd_claiming);
+ wake_up_var_locked(&whole->bd_claiming, &bdev_lock);
}
/**
bd_prepare_to_claim() contains an open-coded version of the new wait_var_event_mutex(). Change it to use that function and re-organise the code to benefit from this change. Signed-off-by: NeilBrown <neilb@suse.de> --- block/bdev.c | 49 +++++++++++++++++++------------------------------ 1 file changed, 19 insertions(+), 30 deletions(-)