pipe: fix check in "set size" fcntl

As it stands this check compares the number of pages to the page size.
This makes no sense and makes the fcntl fail in almost any sane case.

Fix it by checking if nr_pages is not zero (it can become zero only if
arg is too big and round_pipe_size() overflows).

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index f31e2d472984..279eef96c51c 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1215,12 +1215,13 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
                 size = round_pipe_size(arg);
                 nr_pages = size >> PAGE_SHIFT;
 
+                ret = -EINVAL;
+                if (!nr_pages)
+                        goto out;
+
                 if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) {
                         ret = -EPERM;
                         goto out;
-                } else if (nr_pages < PAGE_SIZE) {
-                        ret = -EINVAL;
-                        goto out;
                 }
                 ret = pipe_set_size(pipe, nr_pages);
                 break;