block: fix diskstats access

[linux-2.6-omap-h63xx.git] / include / linux / genhd.h

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 7fbba19e076bedf62b31664c9aaf227953b6e4a6..ac8a901f2002bc96b43d479f1a91814bf73acd2d 100644 (file)
--- 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);