pipe: adjust minimum pipe size to 1 page

We don't need to pages to guarantee the POSIX requirement
that upto a page size write must be atomic to an empty
pipe.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/fs/pipe.c b/fs/pipe.c
index 541d6626f9d93d060541d601494064a825fa7622..369a0245aab65e826a15e7a8e08f287a8a47183d 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1181,13 +1181,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
                if (!capable(CAP_SYS_ADMIN) && nr_pages > pipe_max_pages) {
                        ret = -EPERM;
                        goto out;
-               }
-
-               /*
-                * The pipe needs to be at least 2 pages large to
-                * guarantee POSIX behaviour.
-                */
-               if (arg < 2) {
+               } else if (nr_pages < 1) {
                        ret = -EINVAL;
                        goto out;
                }