blk-mq-sched: add framework for MQ capable IO schedulers

[linux-2.6-block.git] / include / linux / blkdev.h

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 286b2a2643833615633e82d7d9e667b66abbfaef..25564857f5f8de216c7cef8ed77b1f3c6c57075b 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -154,6 +154,7 @@ struct request {
 
        /* the following two fields are internal, NEVER access directly */
        unsigned int __data_len;        /* total data len */
+       int tag;
        sector_t __sector;              /* sector cursor */
 
        struct bio *bio;
@@ -220,9 +221,10 @@ struct request {
 
        unsigned short ioprio;
 
+       int internal_tag;
+
        void *special;          /* opaque pointer available for LLD use */
 
-       int tag;
        int errors;
 
        /*
@@ -288,7 +290,6 @@ enum blk_queue_state {
 struct blk_queue_tag {
        struct request **tag_index;     /* map of busy tags */
        unsigned long *tag_map;         /* bit map of free/busy tags */
-       int busy;                       /* current depth */
        int max_depth;                  /* what we will send to device */
        int real_max_depth;             /* what the array can hold */
        atomic_t refcnt;                /* map can be shared */
@@ -408,7 +409,7 @@ struct request_queue {
        dma_drain_needed_fn     *dma_drain_needed;
        lld_busy_fn             *lld_busy_fn;
 
-       struct blk_mq_ops       *mq_ops;
+       const struct blk_mq_ops *mq_ops;
 
        unsigned int            *mq_map;
 
@@ -1608,6 +1609,25 @@ static inline bool bvec_gap_to_prev(struct request_queue *q,
        return __bvec_gap_to_prev(q, bprv, offset);
 }
 
+/*
+ * Check if the two bvecs from two bios can be merged to one segment.
+ * If yes, no need to check gap between the two bios since the 1st bio
+ * and the 1st bvec in the 2nd bio can be handled in one segment.
+ */
+static inline bool bios_segs_mergeable(struct request_queue *q,
+               struct bio *prev, struct bio_vec *prev_last_bv,
+               struct bio_vec *next_first_bv)
+{
+       if (!BIOVEC_PHYS_MERGEABLE(prev_last_bv, next_first_bv))
+               return false;
+       if (!BIOVEC_SEG_BOUNDARY(q, prev_last_bv, next_first_bv))
+               return false;
+       if (prev->bi_seg_back_size + next_first_bv->bv_len >
+                       queue_max_segment_size(q))
+               return false;
+       return true;
+}
+
 static inline bool bio_will_gap(struct request_queue *q, struct bio *prev,
                         struct bio *next)
 {
@@ -1617,7 +1637,8 @@ static inline bool bio_will_gap(struct request_queue *q, struct bio *prev,
                bio_get_last_bvec(prev, &pb);
                bio_get_first_bvec(next, &nb);
 
-               return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
+               if (!bios_segs_mergeable(q, prev, &pb, &nb))
+                       return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
        }
 
        return false;