From: Nick Piggin <npiggin@suse.de>
Date: Wed, 5 Dec 2007 07:45:25 +0000 (-0800)
Subject: mm: fix XIP file writes
X-Git-Tag: v2.6.24-rc5~75
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=369b8f5a70402d9fe77006cd0044c8a3fcd08430;p=linux-2.6

mm: fix XIP file writes

Writing to XIP files at a non-page-aligned offset results in data corruption
because the writes were always sent to the start of the page.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 32132f3cd6..e233fff61b 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -314,7 +314,7 @@ __xip_file_write(struct file *filp, const char __user *buf,
 		fault_in_pages_readable(buf, bytes);
 		kaddr = kmap_atomic(page, KM_USER0);
 		copied = bytes -
-			__copy_from_user_inatomic_nocache(kaddr, buf, bytes);
+			__copy_from_user_inatomic_nocache(kaddr + offset, buf, bytes);
 		kunmap_atomic(kaddr, KM_USER0);
 		flush_dcache_page(page);