[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>

8 files changed, 23 insertions, 35 deletions

diff --git a/include/asm-alpha/mmu_context.h b/include/asm-alpha/mmu_context.h
index 6f92482cc96..0c017fc181c 100644
--- a/include/asm-alpha/mmu_context.h
+++ b/include/asm-alpha/mmu_context.h
@@ -231,9 +231,8 @@ init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 {
         int i;
 
-        for (i = 0; i < NR_CPUS; i++)
-                if (cpu_online(i))
-                        mm->context[i] = 0;
+        for_each_online_cpu(i)
+                mm->context[i] = 0;
         if (tsk != current)
                 task_thread_info(tsk)->pcb.ptbr
                   = ((unsigned long)mm->pgd - IDENT_ADDR) >> PAGE_SHIFT;
diff --git a/include/asm-alpha/topology.h b/include/asm-alpha/topology.h
index eb740e280d9..420ccde6b91 100644
--- a/include/asm-alpha/topology.h
+++ b/include/asm-alpha/topology.h
@@ -27,8 +27,8 @@ static inline cpumask_t node_to_cpumask(int node)
         cpumask_t node_cpu_mask = CPU_MASK_NONE;
         int cpu;
 
-        for(cpu = 0; cpu < NR_CPUS; cpu++) {
-                if (cpu_online(cpu) && (cpu_to_node(cpu) == node))
+        for_each_online_cpu(cpu) {
+                if (cpu_to_node(cpu) == node)
                         cpu_set(cpu, node_cpu_mask);
         }
 
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 9044aeb3782..78cf45547e3 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -19,10 +19,9 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset[__i], \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset[__i],         \
+                       (src), (size));                          \
 } while (0)
 #else /* ! SMP */
 
diff --git a/include/asm-powerpc/percpu.h b/include/asm-powerpc/percpu.h
index e31922c50e5..464301cd0d0 100644
--- a/include/asm-powerpc/percpu.h
+++ b/include/asm-powerpc/percpu.h
@@ -27,10 +27,9 @@
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset(__i), \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset(__i),         \
+                       (src), (size));                          \
 } while (0)
 
 extern void setup_per_cpu_areas(void);
diff --git a/include/asm-s390/percpu.h b/include/asm-s390/percpu.h
index 123fcaca295..e10ed87094f 100644
--- a/include/asm-s390/percpu.h
+++ b/include/asm-s390/percpu.h
@@ -46,10 +46,9 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset[__i], \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset[__i],         \
+                       (src), (size));                          \
 } while (0)
 
 #else /* ! SMP */
diff --git a/include/asm-sparc64/percpu.h b/include/asm-sparc64/percpu.h
index aea4e51e7cd..82032e159a7 100644
--- a/include/asm-sparc64/percpu.h
+++ b/include/asm-sparc64/percpu.h
@@ -26,10 +26,9 @@ register unsigned long __local_per_cpu_offset asm("g5");
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset(__i), \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset(__i),         \
+                       (src), (size));                          \
 } while (0)
 #else /* ! SMP */
 
diff --git a/include/asm-x86_64/percpu.h b/include/asm-x86_64/percpu.h
index 29a6b0408f7..4405b4adeab 100644
--- a/include/asm-x86_64/percpu.h
+++ b/include/asm-x86_64/percpu.h
@@ -26,10 +26,9 @@
 #define percpu_modcopy(pcpudst, src, size)                      \
 do {                                                            \
         unsigned int __i;                                       \
-        for (__i = 0; __i < NR_CPUS; __i++)                     \
-                if (cpu_possible(__i))                          \
-                        memcpy((pcpudst)+__per_cpu_offset(__i), \
-                               (src), (size));                  \
+        for_each_cpu(__i)                                       \
+                memcpy((pcpudst)+__per_cpu_offset(__i),         \
+                       (src), (size));                          \
 } while (0)
 
 extern void setup_per_cpu_areas(void);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index eef5ccdcd73..fd647fde5ec 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