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| author | Pavel Begunkov <asml.silence@gmail.com> | 2020-12-17 03:24:35 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-12-17 18:40:45 +0300 |
| commit | cda286f0715c82f8117e166afd42cca068876dde (patch) | |
| tree | 1b63e33470acada3fa84b45c68a1d5d888652c52 /fs/io_uring.c | |
| parent | 4bc4a912534a72f1c96f483448f0be16e5a48063 (diff) | |
| download | linux-cda286f0715c82f8117e166afd42cca068876dde.tar.xz | |
io_uring: cancel reqs shouldn't kill overflow list
io_uring_cancel_task_requests() doesn't imply that the ring is going
away, it may continue to work well after that. The problem is that it
sets ->cq_overflow_flushed effectively disabling the CQ overflow feature
Split setting cq_overflow_flushed from flush, and do the first one only
on exit. It's ok in terms of cancellations because there is a
io_uring->in_idle check in __io_cqring_fill_event().
It also fixes a race with setting ->cq_overflow_flushed in
io_uring_cancel_task_requests, whuch's is not atomic and a part of a
bitmask with other flags. Though, the only other flag that's not set
during init is drain_next, so it's not as bad for sane architectures.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Fixes: 0f2122045b946 ("io_uring: don't rely on weak ->files references")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 2d07d35e7262..0d0217281ccf 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1733,10 +1733,6 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force, spin_lock_irqsave(&ctx->completion_lock, flags); - /* if force is set, the ring is going away. always drop after that */ - if (force) - ctx->cq_overflow_flushed = 1; - cqe = NULL; list_for_each_entry_safe(req, tmp, &ctx->cq_overflow_list, compl.list) { if (!io_match_task(req, tsk, files)) @@ -8655,6 +8651,8 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) { mutex_lock(&ctx->uring_lock); percpu_ref_kill(&ctx->refs); + /* if force is set, the ring is going away. always drop after that */ + ctx->cq_overflow_flushed = 1; if (ctx->rings) io_cqring_overflow_flush(ctx, true, NULL, NULL); mutex_unlock(&ctx->uring_lock); |