linux-kernel - [PATCH] tmpfs: shmem_fallocate must return ERESTARTSYS

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Message-ID: <20160304002954.19844.52266.stgit@maxim-thinkpad>
Date:	Thu, 03 Mar 2016 16:30:33 -0800
From:	Maxim Patlasov <mpatlasov@...tuozzo.com>
To:	hughd@...gle.com
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org, devel@...nvz.org
Subject: [PATCH] tmpfs: shmem_fallocate must return ERESTARTSYS

shmem_fallocate() is restartable, so it can return ERESTARTSYS if
signal_pending(). Although fallocate(2) manpage permits EINTR,
the more places use ERESTARTSYS the better.

Signed-off-by: Maxim Patlasov <mpatlasov@...tuozzo.com>
---
 mm/shmem.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 440e2a7..60e9c8a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2229,11 +2229,13 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
 		struct page *page;
 
 		/*
-		 * Good, the fallocate(2) manpage permits EINTR: we may have
-		 * been interrupted because we are using up too much memory.
+		 * Although fallocate(2) manpage permits EINTR, the more
+		 * places use ERESTARTSYS the better. If we have been
+		 * interrupted because we are using up too much memory,
+		 * oom-killer used fatal signal and we will die anyway.
 		 */
 		if (signal_pending(current))
-			error = -EINTR;
+			error = -ERESTARTSYS;
 		else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced)
 			error = -ENOMEM;
 		else