[PATCH] FS-Cache: Fix bounds check

From: David Howells
Date: Wed Jul 13 2011 - 07:48:07 EST


__fscache_uncache_all_inode_pages() has a loop that goes through page index
numbers go up to (loff_t)-1. This is incorrect. The limit should be
(pgoff_t)-1 as on a 32-bit machine the pgoff_t is smaller than loff_t.

On m68k the following error is observed:

fs/fscache/page.c: In function '__fscache_uncache_all_inode_pages':
fs/fscache/page.c:979: warning: comparison is always false due to
limited range of data type

[Should there be a PGOFF_T_MAX constant defined?]

Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

fs/fscache/page.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 60315b3..112359d 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -993,7 +993,7 @@ void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,

pagevec_init(&pvec, 0);
next = 0;
- while (next <= (loff_t)-1 &&
+ while (next <= (pgoff_t)-1 &&
pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)
) {
for (i = 0; i < pagevec_count(&pvec); i++) {

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