From: Jens Axboe <jaxboe@fusionio.com>
Date: Thu, 3 Jun 2010 10:44:30 +0000 (+0200)
Subject: pipe: adjust minimum pipe size to 1 page
X-Git-Tag: v2.6.35-rc2~12^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6a6ca57de92fcae34603551ac944aa74758c30d4;p=platform%2Fupstream%2Fkernel-adaptation-pc.git

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 541d662..369a024 100644
--- 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;
 		}