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 <[email protected]> Cc: Christian Borntraeger <[email protected]> Acked-by: Carsten Otte <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
glzhao · Dec 5, 2007 · 369b8f5 · 369b8f5
1 parent 4670df8
commit 369b8f5
Showing 1 changed file with 1 addition and 1 deletion.
diff --git 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);