io_uring: treat NONBLOCK and RWF_NOWAIT similarly

Make decision making of whether we need to retry read/write similar for
O_NONBLOCK and RWF_NOWAIT. Set REQ_F_NOWAIT when either is specified and
use it for all relevant checks. Also fix resubmitting NOWAIT requests
via io_rw_reissue().

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 bbf8ea8..ce2ea3f 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2734,7 +2734,9 @@ static bool io_rw_reissue(struct io_kiocb *req, long res)
        if (res != -EAGAIN && res != -EOPNOTSUPP)
                return false;
        mode = file_inode(req->file)->i_mode;
-       if ((!S_ISBLK(mode) && !S_ISREG(mode)) || io_wq_current_is_worker())
+       if (!S_ISBLK(mode) && !S_ISREG(mode))
+               return false;
+       if ((req->flags & REQ_F_NOWAIT) || io_wq_current_is_worker())
                return false;
 
        lockdep_assert_held(&req->ctx->uring_lock);
@@ -2907,16 +2909,17 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
        struct io_ring_ctx *ctx = req->ctx;
        struct kiocb *kiocb = &req->rw.kiocb;
+       struct file *file = req->file;
        unsigned ioprio;
        int ret;
 
-       if (S_ISREG(file_inode(req->file)->i_mode))
+       if (S_ISREG(file_inode(file)->i_mode))
                req->flags |= REQ_F_ISREG;
 
        kiocb->ki_pos = READ_ONCE(sqe->off);
-       if (kiocb->ki_pos == -1 && !(req->file->f_mode & FMODE_STREAM)) {
+       if (kiocb->ki_pos == -1 && !(file->f_mode & FMODE_STREAM)) {
                req->flags |= REQ_F_CUR_POS;
-               kiocb->ki_pos = req->file->f_pos;
+               kiocb->ki_pos = file->f_pos;
        }
        kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
        kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
@@ -2924,6 +2927,10 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        if (unlikely(ret))
                return ret;
 
+       /* don't allow async punt for O_NONBLOCK or RWF_NOWAIT */
+       if ((kiocb->ki_flags & IOCB_NOWAIT) || (file->f_flags & O_NONBLOCK))
+               req->flags |= REQ_F_NOWAIT;
+
        ioprio = READ_ONCE(sqe->ioprio);
        if (ioprio) {
                ret = ioprio_check_cap(ioprio);
@@ -2934,10 +2941,6 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        } else
                kiocb->ki_ioprio = get_current_ioprio();
 
-       /* don't allow async punt if RWF_NOWAIT was requested */
-       if (kiocb->ki_flags & IOCB_NOWAIT)
-               req->flags |= REQ_F_NOWAIT;
-
        if (ctx->flags & IORING_SETUP_IOPOLL) {
                if (!(kiocb->ki_flags & IOCB_DIRECT) ||
                    !kiocb->ki_filp->f_op->iopoll)
@@ -3546,15 +3549,14 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
                /* IOPOLL retry should happen for io-wq threads */
                if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
                        goto done;
-               /* no retry on NONBLOCK marked file */
-               if (req->file->f_flags & O_NONBLOCK)
+               /* no retry on NONBLOCK nor RWF_NOWAIT */
+               if (req->flags & REQ_F_NOWAIT)
                        goto done;
                /* some cases will consume bytes even on error returns */
                iov_iter_revert(iter, io_size - iov_iter_count(iter));
                ret = 0;
        } else if (ret <= 0 || ret == io_size || !force_nonblock ||
-                  (req->file->f_flags & O_NONBLOCK) ||
-                  !(req->flags & REQ_F_ISREG)) {
+                  (req->flags & REQ_F_NOWAIT) || !(req->flags & REQ_F_ISREG)) {
                /* read all, failed, already did sync or don't want to retry */
                goto done;
        }
@@ -3675,8 +3677,8 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
         */
        if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
                ret2 = -EAGAIN;
-       /* no retry on NONBLOCK marked file */
-       if (ret2 == -EAGAIN && (req->file->f_flags & O_NONBLOCK))
+       /* no retry on NONBLOCK nor RWF_NOWAIT */
+       if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
                goto done;
        if (!force_nonblock || ret2 != -EAGAIN) {
                /* IOPOLL retry should happen for io-wq threads */