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block: really clone the block cgroup in bio_clone_blkg_association 

bio_clone_blkg_association is supposed to clone the associatation, but
actually ends up doing a search with a tryget.  As we know we have a
reference on the source cgroup just get an unconditional additional
reference to it and call it a day.  That also removes the need for
a RCU critical section.

Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2020-06-27 09:31:48 +02:00 committed by Jens Axboe
parent db9819c76c
commit d92c370a16
1 changed files with 6 additions and 6 deletions
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12
block/bio.c
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@ -1737,12 +1737,12 @@ EXPORT_SYMBOL_GPL(bio_associate_blkg);
*/
void bio_clone_blkg_association(struct bio *dst, struct bio *src)
{
rcu_read_lock();
if (src->bi_blkg)
__bio_associate_blkg(dst, src->bi_blkg);
rcu_read_unlock();
if (src->bi_blkg) {
if (dst->bi_blkg)
blkg_put(dst->bi_blkg);
blkg_get(src->bi_blkg);
dst->bi_blkg = src->bi_blkg;
}
}
EXPORT_SYMBOL_GPL(bio_clone_blkg_association);
#endif /* CONFIG_BLK_CGROUP */