block: change ->make_request_fn() and users to return a queue cookie

No functional changes in this patch, but it prepares us for returning
a more useful cookie related to the IO that was queued up.

Signed-off-by: Jens Axboe <axboe@fb.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>

4 files changed, 28 insertions, 4 deletions

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index e8130138f29d..641e5a3ed58c 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -244,4 +244,28 @@ enum rq_flag_bits {
 #define REQ_MQ_INFLIGHT		(1ULL << __REQ_MQ_INFLIGHT)
 #define REQ_NO_TIMEOUT		(1ULL << __REQ_NO_TIMEOUT)
 
+typedef unsigned int blk_qc_t;
+#define BLK_QC_T_NONE	-1U
+#define BLK_QC_T_SHIFT	16
+
+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)
+{
+	return tag | (queue_num << BLK_QC_T_SHIFT);
+}
+
+static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
+{
+	return cookie >> BLK_QC_T_SHIFT;
+}
+
+static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
+{
+	return cookie & 0xffff;
+}
+
 #endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d045ca8487af..5ee0f5243025 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -209,7 +209,7 @@ static inline unsigned short req_get_ioprio(struct request *req)
 struct blk_queue_ctx;
 
 typedef void (request_fn_proc) (struct request_queue *q);
-typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
+typedef blk_qc_t (make_request_fn) (struct request_queue *q, struct bio *bio);
 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
 
@@ -761,7 +761,7 @@ static inline void rq_flush_dcache_pages(struct request *rq)
 
 extern int blk_register_queue(struct gendisk *disk);
 extern void blk_unregister_queue(struct gendisk *disk);
-extern void generic_make_request(struct bio *bio);
+extern blk_qc_t generic_make_request(struct bio *bio);
 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 extern void blk_put_request(struct request *);
 extern void __blk_put_request(struct request_queue *, struct request *);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 72d8a844c692..bcca36e4bc1e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2625,7 +2625,7 @@ static inline void remove_inode_hash(struct inode *inode)
 extern void inode_sb_list_add(struct inode *inode);
 
 #ifdef CONFIG_BLOCK
-extern void submit_bio(int, struct bio *);
+extern blk_qc_t submit_bio(int, struct bio *);
 extern int bdev_read_only(struct block_device *);
 #endif
 extern int set_blocksize(struct block_device *, int);
diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
index 5ebd70d12f35..69c9057e1ab8 100644
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -426,7 +426,7 @@ static inline struct ppa_addr block_to_ppa(struct nvm_dev *dev,
 	return ppa;
 }
 
-typedef void (nvm_tgt_make_rq_fn)(struct request_queue *, struct bio *);
+typedef blk_qc_t (nvm_tgt_make_rq_fn)(struct request_queue *, struct bio *);
 typedef sector_t (nvm_tgt_capacity_fn)(void *);
 typedef int (nvm_tgt_end_io_fn)(struct nvm_rq *, int);
 typedef void *(nvm_tgt_init_fn)(struct nvm_dev *, struct gendisk *, int, int);