mm: change dirty limit type specifiers to unsigned long

The background dirty and dirty limits are better defined with type
specifiers of unsigned long since negative writeback thresholds are not
possible.

These values, as returned by get_dirty_limits(), are normally compared
with ZVC values to determine whether writeback shall commence or be
throttled.  Such page counts cannot be negative, so declaring the page
limits as signed is unnecessary.

Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 801c08b046e6..6f80beddd8a4 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -24,9 +24,9 @@ static void bdi_debug_init(void)
 static int bdi_debug_stats_show(struct seq_file *m, void *v)
 {
         struct backing_dev_info *bdi = m->private;
-        long background_thresh;
-        long dirty_thresh;
-        long bdi_thresh;
+        unsigned long background_thresh;
+        unsigned long dirty_thresh;
+        unsigned long bdi_thresh;
 
         get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi);