kernel: use lockless list for smp_call_function_single

Make smp_call_function_single and friends more efficient by using a
lockless list.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 6 insertions, 5 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0375654adb28..8678c4322b44 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -95,10 +95,7 @@ enum rq_cmd_type_bits {
  * as well!
  */
 struct request {
-        union {
-                struct list_head queuelist;
-                struct llist_node ll_list;
-        };
+        struct list_head queuelist;
         union {
                 struct call_single_data csd;
                 struct work_struct mq_flush_data;
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 5da22ee42e16..3834f43f9993 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -11,12 +11,16 @@
 #include <linux/list.h>
 #include <linux/cpumask.h>
 #include <linux/init.h>
+#include <linux/llist.h>
 
 extern void cpu_idle(void);
 
 typedef void (*smp_call_func_t)(void *info);
 struct call_single_data {
-        struct list_head list;
+        union {
+                struct list_head list;
+                struct llist_node llist;
+        };
         smp_call_func_t func;
         void *info;
         u16 flags;