}
/**
- * bd_prepare_to_claim - prepare to claim a block device
+ * bd_prepare_to_claim - claim a block device
* @bdev: block device of interest
* @whole: the whole device containing @bdev, may equal @bdev
* @holder: holder trying to claim @bdev
*
- * Prepare to claim @bdev. This function fails if @bdev is already
- * claimed by another holder and waits if another claiming is in
- * progress. This function doesn't actually claim. On successful
- * return, the caller has ownership of bd_claiming and bd_holder[s].
- *
- * CONTEXT:
- * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
- * it multiple times.
+ * Claim @bdev. This function fails if @bdev is already claimed by another
+ * holder and waits if another claiming is in progress. return, the caller
+ * has ownership of bd_claiming and bd_holder[s].
*
* RETURNS:
* 0 if @bdev can be claimed, -EBUSY otherwise.
struct block_device *whole, void *holder)
{
retry:
+ spin_lock(&bdev_lock);
/* if someone else claimed, fail */
- if (!bd_may_claim(bdev, whole, holder))
+ if (!bd_may_claim(bdev, whole, holder)) {
+ spin_unlock(&bdev_lock);
return -EBUSY;
+ }
/* if claiming is already in progress, wait for it to finish */
if (whole->bd_claiming) {
spin_unlock(&bdev_lock);
schedule();
finish_wait(wq, &wait);
- spin_lock(&bdev_lock);
goto retry;
}
/* yay, all mine */
+ whole->bd_claiming = holder;
+ spin_unlock(&bdev_lock);
return 0;
}
if (!whole)
return ERR_PTR(-ENOMEM);
- /* prepare to claim, if successful, mark claiming in progress */
- spin_lock(&bdev_lock);
-
err = bd_prepare_to_claim(bdev, whole, holder);
- if (err == 0) {
- whole->bd_claiming = holder;
- spin_unlock(&bdev_lock);
- return whole;
- } else {
- spin_unlock(&bdev_lock);
+ if (err) {
bdput(whole);
return ERR_PTR(err);
}
+
+ return whole;
}
EXPORT_SYMBOL(bd_start_claiming);