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 <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20241112170050.1612998-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

block/blk-merge.c

@@ -871,11 +871,10 @@ static struct request *attempt_merge(struct request_queue *q,
 		/* 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;
 
@@ -1007,11 +1006,10 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
 		/* 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

@@ -842,7 +842,7 @@ static void blk_print_req_error(struct request *req, blk_status_t status)
 		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)));
 }
 
 /*
@@ -3306,7 +3306,6 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 		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

@@ -156,8 +156,6 @@ struct request {
 	struct blk_crypto_keyslot *crypt_keyslot;
 #endif
 
-	unsigned short ioprio;
-
 	enum mq_rq_state state;
 	atomic_t ref;
 
@@ -221,7 +219,9 @@ static inline bool blk_rq_is_passthrough(struct request *rq)
 
 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)
@@ -984,7 +984,6 @@ static inline void blk_rq_bio_prep(struct request *rq, struct bio *bio,
 	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

@@ -99,7 +99,7 @@ TRACE_EVENT(block_rq_requeue,
 		__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';
@@ -136,7 +136,7 @@ DECLARE_EVENT_CLASS(block_rq_completion,
 		__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';
@@ -209,7 +209,7 @@ DECLARE_EVENT_CLASS(block_rq,
 		__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';