io_uring: allocate io_kiocb upfront

Let io_submit_sqes() to allocate io_kiocb before fetching an sqe.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6524898..d10216d 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2551,30 +2551,23 @@ static int io_queue_link_head(struct io_ring_ctx *ctx, struct io_kiocb *req,
 
 #define SQE_VALID_FLAGS        (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK)
 
-static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
-                         struct io_submit_state *state, struct io_kiocb **link)
+static void io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
+                         struct sqe_submit *s, struct io_submit_state *state,
+                         struct io_kiocb **link)
 {
        struct io_uring_sqe *sqe_copy;
-       struct io_kiocb *req;
        int ret;
 
        /* enforce forwards compatibility on users */
        if (unlikely(s->sqe->flags & ~SQE_VALID_FLAGS)) {
                ret = -EINVAL;
-               goto err;
-       }
-
-       req = io_get_req(ctx, state);
-       if (unlikely(!req)) {
-               ret = -EAGAIN;
-               goto err;
+               goto err_req;
        }
 
        ret = io_req_set_file(ctx, s, state, req);
        if (unlikely(ret)) {
 err_req:
                io_free_req(req, NULL);
-err:
                io_cqring_add_event(ctx, s->sqe->user_data, ret);
                return;
        }
@@ -2710,9 +2703,18 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
 
        for (i = 0; i < nr; i++) {
                struct sqe_submit s;
+               struct io_kiocb *req;
 
-               if (!io_get_sqring(ctx, &s))
+               req = io_get_req(ctx, statep);
+               if (unlikely(!req)) {
+                       if (!submitted)
+                               submitted = -EAGAIN;
                        break;
+               }
+               if (!io_get_sqring(ctx, &s)) {
+                       __io_free_req(req);
+                       break;
+               }
 
                if (io_sqe_needs_user(s.sqe) && !*mm) {
                        mm_fault = mm_fault || !mmget_not_zero(ctx->sqo_mm);
@@ -2740,7 +2742,7 @@ out:
                s.in_async = async;
                s.needs_fixed_file = async;
                trace_io_uring_submit_sqe(ctx, s.sqe->user_data, true, async);
-               io_submit_sqe(ctx, &s, statep, &link);
+               io_submit_sqe(ctx, req, &s, statep, &link);
                submitted++;
 
                /*