[PATCH] pipe: read/write_iter() handler should check for IOCB_NOWAIT

[Jens Axboe]

Pipe read/write only checks for the file O_NONBLOCK flag, but we should
also check for IOCB_NOWAIT for whether or not we should handle this read
or write in a non-blocking fashion. If we don't, then we will block on
data or space for iocbs that explicitly asked for non-blocking
operation. This messes up callers that explicitly ask for non-blocking
operations.

Signed-off-by: Jens Axboe <ax...@kernel.dk>

---

diff --git a/fs/pipe.c b/fs/pipe.c
index 16fb72e9abf7..5711e6bca12d 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -363,7 +363,8 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
                        break;
                if (ret)
                        break;
-               if (filp->f_flags & O_NONBLOCK) {
+               if ((filp->f_flags & O_NONBLOCK) ||
+                   (iocb->ki_flags & IOCB_NOWAIT)) {
                        ret = -EAGAIN;
                        break;
                }
@@ -566,7 +567,8 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
                        continue;
 
                /* Wait for buffer space to become available. */
-               if (filp->f_flags & O_NONBLOCK) {
+               if ((filp->f_flags & O_NONBLOCK) ||
+                   (iocb->ki_flags & IOCB_NOWAIT)) {
                        if (!ret)
                                ret = -EAGAIN;
                        break;

-- 
Jens Axboe