block: remove the ioprio field from struct request

The request ioprio is only initialized from the first attached bio,
so requests without a bio already never set it. Directly use the
bio field instead.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

block/blk-merge.c

···
 		/* Don't merge requests with different write hints. */
 		if (req->bio->bi_write_hint != next->bio->bi_write_hint)
 			return NULL;
+		if (req->bio->bi_ioprio != next->bio->bi_ioprio)
+			return NULL;
 	}
-
-	if (req->ioprio != next->ioprio)
-		return NULL;
 
 	if (!blk_atomic_write_mergeable_rqs(req, next))
 		return NULL;
···
 		/* Don't merge requests with different write hints. */
 		if (rq->bio->bi_write_hint != bio->bi_write_hint)
 			return false;
+		if (rq->bio->bi_ioprio != bio->bi_ioprio)
+			return false;
 	}
-
-	if (rq->ioprio != bio_prio(bio))
-		return false;
 
 	if (blk_atomic_write_mergeable_rq_bio(rq, bio) == false)
 		return false;

block/blk-mq.c

···
 		blk_op_str(req_op(req)),
 		(__force u32)(req->cmd_flags & ~REQ_OP_MASK),
 		req->nr_phys_segments,
-		IOPRIO_PRIO_CLASS(req->ioprio));
+		IOPRIO_PRIO_CLASS(req_get_ioprio(req)));
 }
 
 /*
···
 		rq->special_vec = rq_src->special_vec;
 	}
 	rq->nr_phys_segments = rq_src->nr_phys_segments;
-	rq->ioprio = rq_src->ioprio;
 
 	if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
 		goto free_and_out;

include/linux/blk-mq.h

···
 	struct blk_crypto_keyslot *crypt_keyslot;
 #endif
 
-	unsigned short ioprio;
-
 	enum mq_rq_state state;
 	atomic_t ref;
 
···
 
 static inline unsigned short req_get_ioprio(struct request *req)
 {
-	return req->ioprio;
+	if (req->bio)
+		return req->bio->bi_ioprio;
+	return 0;
 }
 
 #define rq_data_dir(rq)		(op_is_write(req_op(rq)) ? WRITE : READ)
···
 	rq->nr_phys_segments = nr_segs;
 	rq->__data_len = bio->bi_iter.bi_size;
 	rq->bio = rq->biotail = bio;
-	rq->ioprio = bio_prio(bio);
 }
 
 void blk_mq_hctx_set_fq_lock_class(struct blk_mq_hw_ctx *hctx,

include/trace/events/block.h

···
 		__entry->dev	   = rq->q->disk ? disk_devt(rq->q->disk) : 0;
 		__entry->sector    = blk_rq_trace_sector(rq);
 		__entry->nr_sector = blk_rq_trace_nr_sectors(rq);
-		__entry->ioprio    = rq->ioprio;
+		__entry->ioprio    = req_get_ioprio(rq);
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
 		__get_str(cmd)[0] = '\0';
···
 		__entry->sector    = blk_rq_pos(rq);
 		__entry->nr_sector = nr_bytes >> 9;
 		__entry->error     = blk_status_to_errno(error);
-		__entry->ioprio    = rq->ioprio;
+		__entry->ioprio    = req_get_ioprio(rq);
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
 		__get_str(cmd)[0] = '\0';
···
 		__entry->sector    = blk_rq_trace_sector(rq);
 		__entry->nr_sector = blk_rq_trace_nr_sectors(rq);
 		__entry->bytes     = blk_rq_bytes(rq);
-		__entry->ioprio	   = rq->ioprio;
+		__entry->ioprio	   = req_get_ioprio(rq);
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
 		__get_str(cmd)[0] = '\0';