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| author | Pavel Begunkov <asml.silence@gmail.com> | 2021-08-09 13:04:09 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-08-23 13:07:59 -0600 |
| commit | a2416e1ec23c6b79010d03d69c0e4e035339b4ad (patch) | |
| tree | ce91d7608bb518613851c1fb6c5dad37e5188871 /fs/io_uring.c | |
| parent | 864ea921b0300fe5a4db9136b7e307e94b369530 (diff) | |
| download | lwn-a2416e1ec23c6b79010d03d69c0e4e035339b4ad.tar.gz lwn-a2416e1ec23c6b79010d03d69c0e4e035339b4ad.zip | |
io_uring: don't halt iopoll too early
IOPOLL users should care more about getting completions for requests
they submitted, but not in "device did/completed something". Currently,
io_do_iopoll() may return a positive number, which will instruct
io_iopoll_check() to break the loop and end the syscall, even if there
is not enough CQEs or none at all.
Don't return positive numbers, so io_iopoll_check() exits only when it
gets an actual error, need reschedule or got enough CQEs.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/641a88f751623b6758303b3171f0a4141f06726e.1628471125.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 8892747bd173..6a3079a038fb 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2288,7 +2288,6 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, struct io_kiocb *req, *tmp; LIST_HEAD(done); bool spin; - int ret; /* * Only spin for completions if we don't have multiple devices hanging @@ -2296,9 +2295,9 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, */ spin = !ctx->poll_multi_queue && *nr_events < min; - ret = 0; list_for_each_entry_safe(req, tmp, &ctx->iopoll_list, inflight_entry) { struct kiocb *kiocb = &req->rw.kiocb; + int ret; /* * Move completed and retryable entries to our local lists. @@ -2313,22 +2312,20 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, break; ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin); - if (ret < 0) - break; + if (unlikely(ret < 0)) + return ret; + else if (ret) + spin = false; /* iopoll may have completed current req */ if (READ_ONCE(req->iopoll_completed)) list_move_tail(&req->inflight_entry, &done); - - if (ret && spin) - spin = false; - ret = 0; } if (!list_empty(&done)) io_iopoll_complete(ctx, nr_events, &done, resubmit); - return ret; + return 0; } /* |