From c85e9a97c4102ce2e83112da850d838cfab5ab13 Mon Sep 17 00:00:00 2001
From: Wu Fengguang <fengguang.wu@intel.com>
Date: Tue, 2 Feb 2010 13:44:06 -0800
Subject: devmem: fix kmem write bug on memory holes

write_kmem() used to assume vwrite() always return the full buffer length.
However now vwrite() could return 0 to indicate memory hole.  This
creates a bug that "buf" is not advanced accordingly.

Fix it to simply ignore the return value, hence the memory hole.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/char/mem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'drivers/char')

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 1fd4b110d815..48788db4e280 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -555,7 +555,7 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
 				err = -EFAULT;
 				break;
 			}
-			sz = vwrite(kbuf, (char *)p, sz);
+			vwrite(kbuf, (char *)p, sz);
 			count -= sz;
 			buf += sz;
 			virtr += sz;
-- 
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