block: fix non-atomic access to genhd inflight structures

After the stack plugging introduction, these are called lockless.
Ensure that the counters are updated atomically.

Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index c0d5f6945c1e..d764a426e9fd 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -109,7 +109,7 @@ struct hd_struct {
         int make_it_fail;
 #endif
         unsigned long stamp;
-        int in_flight[2];
+        atomic_t in_flight[2];
 #ifdef  CONFIG_SMP
         struct disk_stats __percpu *dkstats;
 #else
@@ -370,21 +370,21 @@ static inline void free_part_stats(struct hd_struct *part)
 
 static inline void part_inc_in_flight(struct hd_struct *part, int rw)
 {
-        part->in_flight[rw]++;
+        atomic_inc(&part->in_flight[rw]);
         if (part->partno)
-                part_to_disk(part)->part0.in_flight[rw]++;
+                atomic_inc(&part_to_disk(part)->part0.in_flight[rw]);
 }
 
 static inline void part_dec_in_flight(struct hd_struct *part, int rw)
 {
-        part->in_flight[rw]--;
+        atomic_dec(&part->in_flight[rw]);
         if (part->partno)
-                part_to_disk(part)->part0.in_flight[rw]--;
+                atomic_dec(&part_to_disk(part)->part0.in_flight[rw]);
 }
 
 static inline int part_in_flight(struct hd_struct *part)
 {
-        return part->in_flight[0] + part->in_flight[1];
+        return atomic_read(&part->in_flight[0]) + atomic_read(&part->in_flight[1]);
 }
 
 static inline struct partition_meta_info *alloc_part_info(struct gendisk *disk)