Re: [PATCH] page->flags corruption fix

[Rik van Riel]

On Wed, 8 Oct 2003, Marcelo Tosatti wrote:

> > A little of the above explanation in the change comment would be nice.
> 
> Maybe comments on top of the code? 
> 
> Rik? :)

Here you are:

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.1193  -> 1.1194 
#	        mm/filemap.c	1.89    -> 1.90   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/10/08	riel@xxxxxxxxxxxxxxxxxxxxxxxx	1.1194
# comment on why the atomic updates are needed, on request
# --------------------------------------------
#
diff -Nru a/mm/filemap.c b/mm/filemap.c
--- a/mm/filemap.c	Wed Oct  8 13:47:12 2003
+++ b/mm/filemap.c	Wed Oct  8 13:47:12 2003
@@ -654,6 +654,12 @@
 	struct address_space *mapping, unsigned long offset,
 	struct page **hash)
 {
+	/*
+	 * Yes this is inefficient, however it is needed.  The problem
+	 * is that we could be adding a page to the swap cache while
+	 * another CPU is also modifying page->flags, so the updates
+	 * really do need to be atomic.  -- Rik
+	 */
 	ClearPageUptodate(page);
 	ClearPageError(page);
 	ClearPageDirty(page);

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/