block: change the request allocation/congestion logic to be sync/async based

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

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 465d6babc847a2603d4f23a5e842cd7dc07b308e..67dae3bd881c28c5aa0b2c9d427c0da834d494ad 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -38,6 +38,10 @@ struct request;
 typedef void (rq_end_io_fn)(struct request *, int);
 
 struct request_list {
+       /*
+        * count[], starved[], and wait[] are indexed by
+        * BLK_RW_SYNC/BLK_RW_ASYNC
+        */
        int count[2];
        int starved[2];
        int elvpriv;
@@ -66,6 +70,11 @@ enum rq_cmd_type_bits {
        REQ_TYPE_ATA_PC,
 };
 
+enum {
+       BLK_RW_ASYNC    = 0,
+       BLK_RW_SYNC     = 1,
+};
+
 /*
  * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
  * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
@@ -103,7 +112,7 @@ enum rq_flag_bits {
        __REQ_QUIET,            /* don't worry about errors */
        __REQ_PREEMPT,          /* set for "ide_preempt" requests */
        __REQ_ORDERED_COLOR,    /* is before or after barrier */
-       __REQ_RW_SYNC,          /* request is sync (O_DIRECT) */
+       __REQ_RW_SYNC,          /* request is sync (sync write or read) */
        __REQ_ALLOCED,          /* request came from our alloc pool */
        __REQ_RW_META,          /* metadata io request */
        __REQ_COPY_USER,        /* contains copies of user pages */
@@ -438,8 +447,8 @@ struct request_queue
 #define QUEUE_FLAG_CLUSTER     0       /* cluster several segments into 1 */
 #define QUEUE_FLAG_QUEUED      1       /* uses generic tag queueing */
 #define QUEUE_FLAG_STOPPED     2       /* queue is stopped */
-#define        QUEUE_FLAG_READFULL     3       /* read queue has been filled */
-#define QUEUE_FLAG_WRITEFULL   4       /* write queue has been filled */
+#define        QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
+#define QUEUE_FLAG_ASYNCFULL   4       /* write queue has been filled */
 #define QUEUE_FLAG_DEAD                5       /* queue being torn down */
 #define QUEUE_FLAG_REENTER     6       /* Re-entrancy avoidance */
 #define QUEUE_FLAG_PLUGGED     7       /* queue is plugged */
@@ -611,32 +620,41 @@ enum {
 #define rq_data_dir(rq)                ((rq)->cmd_flags & 1)
 
 /*
- * We regard a request as sync, if it's a READ or a SYNC write.
+ * We regard a request as sync, if either a read or a sync write
  */
-#define rq_is_sync(rq)         (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
+static inline bool rw_is_sync(unsigned int rw_flags)
+{
+       return !(rw_flags & REQ_RW) || (rw_flags & REQ_RW_SYNC);
+}
+
+static inline bool rq_is_sync(struct request *rq)
+{
+       return rw_is_sync(rq->cmd_flags);
+}
+
 #define rq_is_meta(rq)         ((rq)->cmd_flags & REQ_RW_META)
 
-static inline int blk_queue_full(struct request_queue *q, int rw)
+static inline int blk_queue_full(struct request_queue *q, int sync)
 {
-       if (rw == READ)
-               return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
-       return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
+       if (sync)
+               return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
+       return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
 }
 
-static inline void blk_set_queue_full(struct request_queue *q, int rw)
+static inline void blk_set_queue_full(struct request_queue *q, int sync)
 {
-       if (rw == READ)
-               queue_flag_set(QUEUE_FLAG_READFULL, q);
+       if (sync)
+               queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
        else
-               queue_flag_set(QUEUE_FLAG_WRITEFULL, q);
+               queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
 }
 
-static inline void blk_clear_queue_full(struct request_queue *q, int rw)
+static inline void blk_clear_queue_full(struct request_queue *q, int sync)
 {
-       if (rw == READ)
-               queue_flag_clear(QUEUE_FLAG_READFULL, q);
+       if (sync)
+               queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
        else
-               queue_flag_clear(QUEUE_FLAG_WRITEFULL, q);
+               queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
 }