[PATCH] more for_each_cpu() conversions

When we stop allocating percpu memory for not-possible CPUs we must not touch
the percpu data for not-possible CPUs at all.  The correct way of doing this
is to test cpu_possible() or to use for_each_cpu().

This patch is a kernel-wide sweep of all instances of NR_CPUS.  I found very
few instances of this bug, if any.  But the patch converts lots of open-coded
test to use the preferred helper macros.

Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Kyle McMartin <kyle@parisc-linux.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Christian Zankel <chris@zankel.net>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Jens Axboe <axboe@suse.de>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 10 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index eef5ccdcd731..fd647fde5ec1 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -149,22 +149,16 @@ struct disk_attribute {
 ({                                                                      \
         typeof(gendiskp->dkstats->field) res = 0;                       \
         int i;                                                          \
-        for (i=0; i < NR_CPUS; i++) {                                   \
-                if (!cpu_possible(i))                                   \
-                        continue;                                       \
+        for_each_cpu(i)                                                 \
                 res += per_cpu_ptr(gendiskp->dkstats, i)->field;        \
-        }                                                               \
         res;                                                            \
 })
 
 static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)       {
         int i;
-        for (i=0; i < NR_CPUS; i++) {
-                if (cpu_possible(i)) {
-                        memset(per_cpu_ptr(gendiskp->dkstats, i), value,        
-                                        sizeof (struct disk_stats));
-                }
-        }
+        for_each_cpu(i)
+                memset(per_cpu_ptr(gendiskp->dkstats, i), value,
+                                sizeof (struct disk_stats));
 }               
                                 
 #else