tree 54917292e4e39a04f4d2aba88f32bc92f4042e23
parent 4ba09f69e20d0a768d91277847ddbd31f476590e
author Jens Axboe <axboe@kernel.dk> 1544481953 -0700
committer Jens Axboe <axboe@kernel.dk> 1544490634 -0700

dm: fix inflight IO check

After switching to percpu inflight counters, the inflight check
is totally buggy. It's perfectly valid for some counters to be
non-zero while having a total inflight IO count of 0, that's how
these kinds of counters work (inc on one CPU, dec on another).
Fix the md_in_flight() check to sum all counters before returning
a false positive, potentially.

While at it, remove the inflight read for IO completion. We don't
need it, just wake anyone that's waiting for the IO count to drop
to zero. The caller needs to re-check that value anyway when woken,
which it does.

Fixes: 6f75723190d8 ("dm: remove the pending IO accounting")
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>