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authorPavel Begunkov <asml.silence@gmail.com>2020-07-23 19:25:20 +0200
committerJens Axboe <axboe@kernel.dk>2020-07-24 21:00:46 +0200
commitae34817bd93e373a03203a4c6892735c430a14e1 (patch)
tree36e31c3d6eb575289ab4ad10a293c661fa3b8396
parentio_uring: clear IORING_SQ_NEED_WAKEUP after executing task works (diff)
downloadlinux-ae34817bd93e373a03203a4c6892735c430a14e1.tar.xz
linux-ae34817bd93e373a03203a4c6892735c430a14e1.zip
io_uring: don't do opcode prep twice
Calling into opcode prep handlers may be dangerous, as they re-read SQE but might not re-initialise requests completely. If io_req_defer() passed fast checks and is done with preparations, punt it async. As all other cases are covered with nulling @sqe, this guarantees that io_[opcode]_prep() are visited only once per request. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/io_uring.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6f3f18a99f4f..38e4c3902963 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5447,7 +5447,8 @@ static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
spin_unlock_irq(&ctx->completion_lock);
kfree(de);
- return 0;
+ io_queue_async_work(req);
+ return -EIOCBQUEUED;
}
trace_io_uring_defer(ctx, req, req->user_data);