1 files changed, 18 insertions, 9 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1a23722e8878..0e67c45b3bc9 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -73,7 +73,7 @@ enum rq_cmd_type_bits {
 
 /*
  * try to put the fields that are referenced together in the same cacheline.
- * if you modify this structure, be sure to check block/blk-core.c:rq_init()
+ * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
  * as well!
  */
 struct request {
@@ -260,8 +260,7 @@ struct queue_limits {
         unsigned char           discard_zeroes_data;
 };
 
-struct request_queue
-{
+struct request_queue {
         /*
          * Together with queue_head for cacheline sharing
          */
@@ -304,14 +303,14 @@ struct request_queue
         void                    *queuedata;
 
         /*
-         * queue needs bounce pages for pages above this limit
+         * various queue flags, see QUEUE_* below
          */
-        gfp_t                   bounce_gfp;
+        unsigned long           queue_flags;
 
         /*
-         * various queue flags, see QUEUE_* below
+         * queue needs bounce pages for pages above this limit
          */
-        unsigned long           queue_flags;
+        gfp_t                   bounce_gfp;
 
         /*
          * protects queue structures from reentrancy. ->__queue_lock should
@@ -334,8 +333,8 @@ struct request_queue
         unsigned int            nr_congestion_off;
         unsigned int            nr_batching;
 
-        void                    *dma_drain_buffer;
         unsigned int            dma_drain_size;
+        void                    *dma_drain_buffer;
         unsigned int            dma_pad_mask;
         unsigned int            dma_alignment;
 
@@ -393,7 +392,7 @@ struct request_queue
 #define QUEUE_FLAG_ELVSWITCH    6       /* don't use elevator, just do FIFO */
 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
-#define QUEUE_FLAG_SAME_COMP    9       /* force complete on same CPU */
+#define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
@@ -403,6 +402,7 @@ struct request_queue
 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
+#define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
 
 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
@@ -857,12 +857,21 @@ struct request_queue *blk_alloc_queue(gfp_t);
 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 extern void blk_put_queue(struct request_queue *);
 
+/*
+ * Note: Code in between changing the blk_plug list/cb_list or element of such
+ * lists is preemptable, but such code can't do sleep (or be very careful),
+ * otherwise data is corrupted. For details, please check schedule() where
+ * blk_schedule_flush_plug() is called.
+ */
 struct blk_plug {
         unsigned long magic;
         struct list_head list;
         struct list_head cb_list;
         unsigned int should_sort;
+        unsigned int count;
 };
+#define BLK_MAX_REQUEST_COUNT 16
+
 struct blk_plug_cb {
         struct list_head list;
         void (*callback)(struct blk_plug_cb *);