FS-Cache: Fix __fscache_uncache_all_inode_pages()'s outer loop

commit b307d4655a71749ac3f91c6dbe33d28cc026ceeb upstream.

The compiler, at least for ix86 and m68k, validly warns that the
comparison:

	next <= (loff_t)-1

is always true (and it's always true also for x86-64 and probably all
other arches - as long as pgoff_t isn't wider than loff_t).  The
intention appears to be to avoid wrapping of "next", so rather than
eliminating the pointless comparison, fix the loop to indeed get exited
when "next" would otherwise wrap.

On m68k the following warning 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

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Suresh Jayaraman <sjayaraman@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 52b59e2a4af6e85029ec2145702e11673edfa605..fd03b0e427f93f8382dc3cc660aab5dd8197cf5b 100644 (file)
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -989,16 +989,12 @@ void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
 
        pagevec_init(&pvec, 0);
        next = 0;
-       while (next <= (loff_t)-1 &&
-              pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)
-              ) {
+       do {
+               if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
+                       break;
                for (i = 0; i < pagevec_count(&pvec); i++) {
                        struct page *page = pvec.pages[i];
-                       pgoff_t page_index = page->index;
-
-                       ASSERTCMP(page_index, >=, next);
-                       next = page_index + 1;
-
+                       next = page->index;
                        if (PageFsCache(page)) {
                                __fscache_wait_on_page_write(cookie, page);
                                __fscache_uncache_page(cookie, page);
@@ -1006,7 +1002,7 @@ void __fscache_uncache_all_inode_pages(struct fscache_cookie *cookie,
                }
                pagevec_release(&pvec);
                cond_resched();
-       }
+       } while (++next);
 
        _leave("");
 }