[PATCH 5.8 137/464] io_uring: fix stalled deferred requests

From: Greg Kroah-Hartman
Date: Mon Aug 17 2020 - 15:42:19 EST


From: Pavel Begunkov <asml.silence@xxxxxxxxx>

[ Upstream commit dd9dfcdf5a603680458f5e7b0d2273c66e5417db ]

Always do io_commit_cqring() after completing a request, even if it was
accounted as overflowed on the CQ side. Failing to do that may lead to
not to pushing deferred requests when needed, and so stalling the whole
ring.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/io_uring.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1d8761a9f3b88..1619ca74b44d9 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7538,6 +7538,7 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
}
WRITE_ONCE(ctx->rings->cq_overflow,
atomic_inc_return(&ctx->cached_cq_overflow));
+ io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);

/*
--
2.25.1