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block: don't assume last put of shared tags is for the host

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There is no inherent reason why the last put of a tag structure must be
the one for the Scsi_Host, as device model objects can be held for
arbitrary periods.  Merge blk_free_tags and __blk_free_tags into a single
funtion that just release a references and get rid of the BUG() when the
host reference wasn't the last.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig 2014-07-08 12:25:28 +02:00 committed by Jens Axboe
parent 448bfad8a1
commit d45b3279a5
1 changed files with 7 additions and 26 deletions
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33
block/blk-tag.c
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@ -27,18 +27,15 @@ struct request *blk_queue_find_tag(struct request_queue *q, int tag)
EXPORT_SYMBOL(blk_queue_find_tag);
/**
* __blk_free_tags - release a given set of tag maintenance info
* blk_free_tags - release a given set of tag maintenance info
* @bqt: the tag map to free
*
* Tries to free the specified @bqt. Returns true if it was
* actually freed and false if there are still references using it
* Drop the reference count on @bqt and frees it when the last reference
* is dropped.
*/
static int __blk_free_tags(struct blk_queue_tag *bqt)
void blk_free_tags(struct blk_queue_tag *bqt)
{
int retval;
retval = atomic_dec_and_test(&bqt->refcnt);
if (retval) {
if (atomic_dec_and_test(&bqt->refcnt)) {
BUG_ON(find_first_bit(bqt->tag_map, bqt->max_depth) <
bqt->max_depth);
@ -50,9 +47,8 @@ static int __blk_free_tags(struct blk_queue_tag *bqt)
kfree(bqt);
}
return retval;
}
EXPORT_SYMBOL(blk_free_tags);
/**
* __blk_queue_free_tags - release tag maintenance info
@ -69,27 +65,12 @@ void __blk_queue_free_tags(struct request_queue *q)
if (!bqt)
return;
__blk_free_tags(bqt);
blk_free_tags(bqt);
q->queue_tags = NULL;
queue_flag_clear_unlocked(QUEUE_FLAG_QUEUED, q);
}
/**
* blk_free_tags - release a given set of tag maintenance info
* @bqt: the tag map to free
*
* For externally managed @bqt frees the map. Callers of this
* function must guarantee to have released all the queues that
* might have been using this tag map.
*/
void blk_free_tags(struct blk_queue_tag *bqt)
{
if (unlikely(!__blk_free_tags(bqt)))
BUG();
}
EXPORT_SYMBOL(blk_free_tags);
/**
* blk_queue_free_tags - release tag maintenance info
* @q: the request queue for the device