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authorJens Axboe <axboe@kernel.dk>2023-03-07 17:56:28 -0700
committerJens Axboe <axboe@kernel.dk>2023-04-25 14:08:59 -0600
commitafed6271f5b0d78ca1a3739c1da4aa3629b26bba (patch)
tree33691f325a88cedf1241a01e02522ee0f4c1096b
parent0f99fc513ddd28de155c58547824a9fd63daacea (diff)
pipe: set FMODE_NOWAIT on pipes
Pipes themselves do not hold the the pipe lock across IO, and hence are safe for RWF_NOWAIT/IOCB_NOWAIT usage. The "contract" for NOWAIT is really "should not do IO under this lock", not strictly that we cannot block or that the below code is in any way atomic. Pipes fulfil that criteria. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/pipe.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index 42c7ff41c2db..ceb17d2dfa19 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -976,6 +976,9 @@ static int __do_pipe_flags(int *fd, struct file **files, int flags)
audit_fd_pair(fdr, fdw);
fd[0] = fdr;
fd[1] = fdw;
+ /* pipe groks IOCB_NOWAIT */
+ files[0]->f_mode |= FMODE_NOWAIT;
+ files[1]->f_mode |= FMODE_NOWAIT;
return 0;
err_fdr: