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authorPavel Begunkov <asml.silence@gmail.com>2019-12-18 19:53:45 +0300
committerJens Axboe <axboe@kernel.dk>2019-12-18 10:01:49 -0700
commit7c504e65206a4379ff38fe41d21b32b6c2c3e53e (patch)
tree7badbc25ff49df5c2493cd5516b9dcbdfa8d7b50
parente781573e2fb1b75acdba61dcb9bcbfc16f288442 (diff)
io_uring: don't wait when under-submitting
There is no reliable way to submit and wait in a single syscall, as io_submit_sqes() may under-consume sqes (in case of an early error). Then it will wait for not-yet-submitted requests, deadlocking the user in most cases. Don't wait/poll if can't submit all sqes Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/io_uring.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1d4e7332ccae..81e7fe6dee18 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5135,6 +5135,9 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
submitted = io_submit_sqes(ctx, to_submit, f.file, fd,
&cur_mm, false);
mutex_unlock(&ctx->uring_lock);
+
+ if (submitted != to_submit)
+ goto out;
}
if (flags & IORING_ENTER_GETEVENTS) {
unsigned nr_events = 0;
@@ -5148,6 +5151,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
}
}
+out:
percpu_ref_put(&ctx->refs);
out_fput:
fdput(f);