| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.5 108/151] blk-iocost: fix incorrect vtime comparison in iocg_is_idle() | Date | Tue, 17 Mar 2020 11:55:18 +0100 |
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From: Tejun Heo <tj@kernel.org>
commit dcd6589b11d3b1e71f516a87a7b9646ed356b4c0 upstream.
vtimes may wrap and time_before/after64() should be used to determine whether a given vtime is before or after another. iocg_is_idle() was incorrectly using plain "<" comparison do determine whether done_vtime is before vtime. Here, the only thing we're interested in is whether done_vtime matches vtime which indicates that there's nothing in flight. Let's test for inequality instead.
Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- block/blk-iocost.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -1318,7 +1318,7 @@ static bool iocg_is_idle(struct ioc_gq * return false; /* is something in flight? */ - if (atomic64_read(&iocg->done_vtime) < atomic64_read(&iocg->vtime)) + if (atomic64_read(&iocg->done_vtime) != atomic64_read(&iocg->vtime)) return false; return true;
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