1 files changed, 57 insertions, 82 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 7fbba19e076b..ac8a901f2002 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -209,16 +209,24 @@ extern void disk_part_iter_exit(struct disk_part_iter *piter);
 extern struct hd_struct *disk_map_sector_rcu(struct gendisk *disk,
                                              sector_t sector);
 
-/* 
+/*
  * Macros to operate on percpu disk statistics:
  *
- * The __ variants should only be called in critical sections. The full
- * variants disable/enable preemption.
+ * {disk|part|all}_stat_{add|sub|inc|dec}() modify the stat counters
+ * and should be called between disk_stat_lock() and
+ * disk_stat_unlock().
+ *
+ * part_stat_read() can be called at any time.
+ *
+ * part_stat_{add|set_all}() and {init|free}_part_stats are for
+ * internal use only.
  */
-
 #ifdef  CONFIG_SMP
-#define __disk_stat_add(gendiskp, field, addnd)         \
-        (per_cpu_ptr(gendiskp->dkstats, smp_processor_id())->field += addnd)
+#define disk_stat_lock()        ({ rcu_read_lock(); get_cpu(); })
+#define disk_stat_unlock()      do { put_cpu(); rcu_read_unlock(); } while (0)
+
+#define disk_stat_add(cpu, gendiskp, field, addnd)                      \
+        (per_cpu_ptr(gendiskp->dkstats, cpu)->field += addnd)
 
 #define disk_stat_read(gendiskp, field)                                 \
 ({                                                                      \
@@ -229,7 +237,8 @@ extern struct hd_struct *disk_map_sector_rcu(struct gendisk *disk,
         res;                                                            \
 })
 
-static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)       {
+static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)
+{
         int i;
 
         for_each_possible_cpu(i)
@@ -237,14 +246,14 @@ static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)	{
                                 sizeof(struct disk_stats));
 }               
 
-#define __part_stat_add(part, field, addnd)                             \
-        (per_cpu_ptr(part->dkstats, smp_processor_id())->field += addnd)
+#define part_stat_add(cpu, part, field, addnd)                          \
+        (per_cpu_ptr(part->dkstats, cpu)->field += addnd)
 
-#define __all_stat_add(gendiskp, part, field, addnd, sector)    \
-({                                                              \
-        if (part)                                               \
-                __part_stat_add(part, field, addnd);            \
-        __disk_stat_add(gendiskp, field, addnd);                \
+#define all_stat_add(cpu, gendiskp, part, field, addnd, sector)         \
+({                                                                      \
+        if (part)                                                       \
+                part_stat_add(cpu, part, field, addnd);                 \
+        disk_stat_add(cpu, gendiskp, field, addnd);                     \
 })
 
 #define part_stat_read(part, field)                                     \
@@ -264,10 +273,13 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
                 memset(per_cpu_ptr(part->dkstats, i), value,
                                 sizeof(struct disk_stats));
 }
-                                
+
 #else /* !CONFIG_SMP */
-#define __disk_stat_add(gendiskp, field, addnd) \
-                                (gendiskp->dkstats.field += addnd)
+#define disk_stat_lock()        ({ rcu_read_lock(); 0; })
+#define disk_stat_unlock()      rcu_read_unlock()
+
+#define disk_stat_add(cpu, gendiskp, field, addnd)                      \
+        (gendiskp->dkstats.field += addnd)
 #define disk_stat_read(gendiskp, field) (gendiskp->dkstats.field)
 
 static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)
@@ -275,14 +287,14 @@ static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)
         memset(&gendiskp->dkstats, value, sizeof (struct disk_stats));
 }
 
-#define __part_stat_add(part, field, addnd) \
+#define part_stat_add(cpu, part, field, addnd)                          \
         (part->dkstats.field += addnd)
 
-#define __all_stat_add(gendiskp, part, field, addnd, sector)    \
-({                                                              \
-        if (part)                                               \
-                part->dkstats.field += addnd;                   \
-        __disk_stat_add(gendiskp, field, addnd);                \
+#define all_stat_add(cpu, gendiskp, part, field, addnd, sector)         \
+({                                                                      \
+        if (part)                                                       \
+                part_stat_add(cpu, part, field, addnd);                 \
+        disk_stat_add(cpu, gendiskp, field, addnd);                     \
 })
 
 #define part_stat_read(part, field)     (part->dkstats.field)
@@ -294,63 +306,26 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
 
 #endif /* CONFIG_SMP */
 
-#define disk_stat_add(gendiskp, field, addnd)                   \
-        do {                                                    \
-                preempt_disable();                              \
-                __disk_stat_add(gendiskp, field, addnd);        \
-                preempt_enable();                               \
-        } while (0)
-
-#define __disk_stat_dec(gendiskp, field) __disk_stat_add(gendiskp, field, -1)
-#define disk_stat_dec(gendiskp, field) disk_stat_add(gendiskp, field, -1)
-
-#define __disk_stat_inc(gendiskp, field) __disk_stat_add(gendiskp, field, 1)
-#define disk_stat_inc(gendiskp, field) disk_stat_add(gendiskp, field, 1)
-
-#define __disk_stat_sub(gendiskp, field, subnd) \
-                __disk_stat_add(gendiskp, field, -subnd)
-#define disk_stat_sub(gendiskp, field, subnd) \
-                disk_stat_add(gendiskp, field, -subnd)
-
-#define part_stat_add(gendiskp, field, addnd)           \
-        do {                                            \
-                preempt_disable();                      \
-                __part_stat_add(gendiskp, field, addnd);\
-                preempt_enable();                       \
-        } while (0)
-
-#define __part_stat_dec(gendiskp, field) __part_stat_add(gendiskp, field, -1)
-#define part_stat_dec(gendiskp, field) part_stat_add(gendiskp, field, -1)
-
-#define __part_stat_inc(gendiskp, field) __part_stat_add(gendiskp, field, 1)
-#define part_stat_inc(gendiskp, field) part_stat_add(gendiskp, field, 1)
-
-#define __part_stat_sub(gendiskp, field, subnd) \
-                __part_stat_add(gendiskp, field, -subnd)
-#define part_stat_sub(gendiskp, field, subnd) \
-                part_stat_add(gendiskp, field, -subnd)
-
-#define all_stat_add(gendiskp, part, field, addnd, sector)      \
-        do {                                                    \
-                preempt_disable();                              \
-                __all_stat_add(gendiskp, part, field, addnd, sector);   \
-                preempt_enable();                               \
-        } while (0)
-
-#define __all_stat_dec(gendiskp, field, sector) \
-                __all_stat_add(gendiskp, field, -1, sector)
-#define all_stat_dec(gendiskp, field, sector) \
-                all_stat_add(gendiskp, field, -1, sector)
-
-#define __all_stat_inc(gendiskp, part, field, sector) \
-                __all_stat_add(gendiskp, part, field, 1, sector)
-#define all_stat_inc(gendiskp, part, field, sector) \
-                all_stat_add(gendiskp, part, field, 1, sector)
-
-#define __all_stat_sub(gendiskp, part, field, subnd, sector) \
-                __all_stat_add(gendiskp, part, field, -subnd, sector)
-#define all_stat_sub(gendiskp, part, field, subnd, sector) \
-                all_stat_add(gendiskp, part, field, -subnd, sector)
+#define disk_stat_dec(cpu, gendiskp, field)                             \
+        disk_stat_add(cpu, gendiskp, field, -1)
+#define disk_stat_inc(cpu, gendiskp, field)                             \
+        disk_stat_add(cpu, gendiskp, field, 1)
+#define disk_stat_sub(cpu, gendiskp, field, subnd)                      \
+        disk_stat_add(cpu, gendiskp, field, -subnd)
+
+#define part_stat_dec(cpu, gendiskp, field)                             \
+        part_stat_add(cpu, gendiskp, field, -1)
+#define part_stat_inc(cpu, gendiskp, field)                             \
+        part_stat_add(cpu, gendiskp, field, 1)
+#define part_stat_sub(cpu, gendiskp, field, subnd)                      \
+        part_stat_add(cpu, gendiskp, field, -subnd)
+
+#define all_stat_dec(cpu, gendiskp, field, sector)                      \
+        all_stat_add(cpu, gendiskp, field, -1, sector)
+#define all_stat_inc(cpu, gendiskp, part, field, sector)                \
+        all_stat_add(cpu, gendiskp, part, field, 1, sector)
+#define all_stat_sub(cpu, gendiskp, part, field, subnd, sector)         \
+        all_stat_add(cpu, gendiskp, part, field, -subnd, sector)
 
 /* Inlines to alloc and free disk stats in struct gendisk */
 #ifdef  CONFIG_SMP
@@ -401,8 +376,8 @@ static inline void free_part_stats(struct hd_struct *part)
 #endif  /* CONFIG_SMP */
 
 /* drivers/block/ll_rw_blk.c */
-extern void disk_round_stats(struct gendisk *disk);
-extern void part_round_stats(struct hd_struct *part);
+extern void disk_round_stats(int cpu, struct gendisk *disk);
+extern void part_round_stats(int cpu, struct hd_struct *part);
 
 /* drivers/block/genhd.c */
 extern int get_blkdev_list(char *, int);