blk-mq: add support for carrying internal tag information in blk_qc_t

No functional change in this patch, just in preparation for having
two types of tags available to the block layer for a single request.

Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index fcdeadc5575305a4fdb47f8820dd12d3d8801445..d40be641f3d59402990b8f59b5bc7e07d3e84f7a 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1308,6 +1308,11 @@ static struct request *blk_mq_map_request(struct request_queue *q,
        return rq;
 }
 
+static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq)
+{
+       return blk_tag_to_qc_t(rq->tag, hctx->queue_num, false);
+}
+
 static void blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie)
 {
        int ret;
@@ -1318,7 +1323,7 @@ static void blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie)
                .list = NULL,
                .last = 1
        };
-       blk_qc_t new_cookie = blk_tag_to_qc_t(rq->tag, hctx->queue_num);
+       blk_qc_t new_cookie = request_to_qc_t(hctx, rq);
 
        if (blk_mq_hctx_stopped(hctx))
                goto insert;
@@ -1387,7 +1392,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 
        wbt_track(&rq->issue_stat, wb_acct);
 
-       cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
+       cookie = request_to_qc_t(data.hctx, rq);
 
        if (unlikely(is_flush_fua)) {
                blk_mq_bio_to_request(rq, bio);
@@ -1496,7 +1501,7 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
 
        wbt_track(&rq->issue_stat, wb_acct);
 
-       cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
+       cookie = request_to_qc_t(data.hctx, rq);
 
        if (unlikely(is_flush_fua)) {
                blk_mq_bio_to_request(rq, bio);

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 519ea2c9df612becf997cf8fafbc1411ce6cd4be..0e5b1cd5113c068c67dec5fa50eab7caf83af69a 100644 (file)
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -232,22 +232,29 @@ static inline bool op_is_sync(unsigned int op)
 }
 
 typedef unsigned int blk_qc_t;
-#define BLK_QC_T_NONE  -1U
-#define BLK_QC_T_SHIFT 16
+#define BLK_QC_T_NONE          -1U
+#define BLK_QC_T_SHIFT         16
+#define BLK_QC_T_INTERNAL      (1U << 31)
 
 static inline bool blk_qc_t_valid(blk_qc_t cookie)
 {
        return cookie != BLK_QC_T_NONE;
 }
 
-static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num)
+static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
+                                      bool internal)
 {
-       return tag | (queue_num << BLK_QC_T_SHIFT);
+       blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);
+
+       if (internal)
+               ret |= BLK_QC_T_INTERNAL;
+
+       return ret;
 }
 
 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 {
-       return cookie >> BLK_QC_T_SHIFT;
+       return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
 }
 
 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
@@ -255,6 +262,11 @@ static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
        return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
 }
 
+static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
+{
+       return (cookie & BLK_QC_T_INTERNAL) != 0;
+}
+
 struct blk_issue_stat {
        u64 time;
 };