null_blk: fix zoned support for non-rq based operation

The supported added for zones in null_blk seem to assume that only rq
based operation is possible. But this depends on the queue_mode setting,
if this is set to 0, then cmd->bio is what we need to be operating on.
Right now any attempt to load null_blk with queue_mode=0 will
insta-crash, since cmd->rq is NULL and null_handle_cmd() assumes it to
always be set.

Make the zoned code deal with bio's instead, or pass in the
appropriate sector/nr_sectors instead.

Fixes: ca4b2a01 ("null_blk: add zone support")
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/null_blk.h

@@ -87,10 +87,10 @@ struct nullb {
 #ifdef CONFIG_BLK_DEV_ZONED
 int null_zone_init(struct nullb_device *dev);
 void null_zone_exit(struct nullb_device *dev);
-blk_status_t null_zone_report(struct nullb *nullb,
-					    struct nullb_cmd *cmd);
-void null_zone_write(struct nullb_cmd *cmd);
-void null_zone_reset(struct nullb_cmd *cmd);
+blk_status_t null_zone_report(struct nullb *nullb, struct bio *bio);
+void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
+			unsigned int nr_sectors);
+void null_zone_reset(struct nullb_cmd *cmd, sector_t sector);
 #else
 static inline int null_zone_init(struct nullb_device *dev)
 {
@@ -98,11 +98,14 @@ static inline int null_zone_init(struct nullb_device *dev)
 }
 static inline void null_zone_exit(struct nullb_device *dev) {}
 static inline blk_status_t null_zone_report(struct nullb *nullb,
-					    struct nullb_cmd *cmd)
+					    struct bio *bio)
 {
 	return BLK_STS_NOTSUPP;
 }
-static inline void null_zone_write(struct nullb_cmd *cmd) {}
-static inline void null_zone_reset(struct nullb_cmd *cmd) {}
+static inline void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
+				   unsigned int nr_sectors)
+{
+}
+static inline void null_zone_reset(struct nullb_cmd *cmd, sector_t sector) {}
 #endif /* CONFIG_BLK_DEV_ZONED */
 #endif /* __NULL_BLK_H */

drivers/block/null_blk_main.c

@@ -1157,16 +1157,33 @@ static void null_restart_queue_async(struct nullb *nullb)
 	}
 }
 
+static bool cmd_report_zone(struct nullb *nullb, struct nullb_cmd *cmd)
+{
+	struct nullb_device *dev = cmd->nq->dev;
+
+	if (dev->queue_mode == NULL_Q_BIO) {
+		if (bio_op(cmd->bio) == REQ_OP_ZONE_REPORT) {
+			cmd->error = null_zone_report(nullb, cmd->bio);
+			return true;
+		}
+	} else {
+		if (req_op(cmd->rq) == REQ_OP_ZONE_REPORT) {
+			cmd->error = null_zone_report(nullb, cmd->rq->bio);
+			return true;
+		}
+	}
+
+	return false;
+}
+
 static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
 {
 	struct nullb_device *dev = cmd->nq->dev;
 	struct nullb *nullb = dev->nullb;
 	int err = 0;
 
-	if (req_op(cmd->rq) == REQ_OP_ZONE_REPORT) {
-		cmd->error = null_zone_report(nullb, cmd);
+	if (cmd_report_zone(nullb, cmd))
 		goto out;
-	}
 
 	if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
 		struct request *rq = cmd->rq;
@@ -1234,10 +1251,24 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
 	cmd->error = errno_to_blk_status(err);
 
 	if (!cmd->error && dev->zoned) {
-		if (req_op(cmd->rq) == REQ_OP_WRITE)
-			null_zone_write(cmd);
-		else if (req_op(cmd->rq) == REQ_OP_ZONE_RESET)
-			null_zone_reset(cmd);
+		sector_t sector;
+		unsigned int nr_sectors;
+		int op;
+
+		if (dev->queue_mode == NULL_Q_BIO) {
+			op = bio_op(cmd->bio);
+			sector = cmd->bio->bi_iter.bi_sector;
+			nr_sectors = cmd->bio->bi_iter.bi_size >> 9;
+		} else {
+			op = req_op(cmd->rq);
+			sector = blk_rq_pos(cmd->rq);
+			nr_sectors = blk_rq_sectors(cmd->rq);
+		}
+
+		if (op == REQ_OP_WRITE)
+			null_zone_write(cmd, sector, nr_sectors);
+		else if (op == REQ_OP_ZONE_RESET)
+			null_zone_reset(cmd, sector);
 	}
 out:
 	/* Complete IO by inline, softirq or timer */

drivers/block/null_blk_zoned.c

@@ -48,7 +48,7 @@ void null_zone_exit(struct nullb_device *dev)
 	kvfree(dev->zones);
 }
 
-static void null_zone_fill_rq(struct nullb_device *dev, struct request *rq,
+static void null_zone_fill_bio(struct nullb_device *dev, struct bio *bio,
 			       unsigned int zno, unsigned int nr_zones)
 {
 	struct blk_zone_report_hdr *hdr = NULL;
@@ -57,7 +57,7 @@ static void null_zone_fill_rq(struct nullb_device *dev, struct request *rq,
 	void *addr;
 	unsigned int zones_to_cpy;
 
-	bio_for_each_segment(bvec, rq->bio, iter) {
+	bio_for_each_segment(bvec, bio, iter) {
 		addr = kmap_atomic(bvec.bv_page);
 
 		zones_to_cpy = bvec.bv_len / sizeof(struct blk_zone);
@@ -84,29 +84,24 @@ static void null_zone_fill_rq(struct nullb_device *dev, struct request *rq,
 	}
 }
 
-blk_status_t null_zone_report(struct nullb *nullb,
-				     struct nullb_cmd *cmd)
+blk_status_t null_zone_report(struct nullb *nullb, struct bio *bio)
 {
 	struct nullb_device *dev = nullb->dev;
-	struct request *rq = cmd->rq;
-	unsigned int zno = null_zone_no(dev, blk_rq_pos(rq));
+	unsigned int zno = null_zone_no(dev, bio->bi_iter.bi_sector);
 	unsigned int nr_zones = dev->nr_zones - zno;
-	unsigned int max_zones = (blk_rq_bytes(rq) /
-					sizeof(struct blk_zone)) - 1;
+	unsigned int max_zones;
 
+	max_zones = (bio->bi_iter.bi_size / sizeof(struct blk_zone)) - 1;
 	nr_zones = min_t(unsigned int, nr_zones, max_zones);
-
-	null_zone_fill_rq(nullb->dev, rq, zno, nr_zones);
+	null_zone_fill_bio(nullb->dev, bio, zno, nr_zones);
 
 	return BLK_STS_OK;
 }
 
-void null_zone_write(struct nullb_cmd *cmd)
+void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
+		     unsigned int nr_sectors)
 {
 	struct nullb_device *dev = cmd->nq->dev;
-	struct request *rq = cmd->rq;
-	sector_t sector = blk_rq_pos(rq);
-	unsigned int rq_sectors = blk_rq_sectors(rq);
 	unsigned int zno = null_zone_no(dev, sector);
 	struct blk_zone *zone = &dev->zones[zno];
 
@@ -118,7 +113,7 @@ void null_zone_write(struct nullb_cmd *cmd)
 	case BLK_ZONE_COND_EMPTY:
 	case BLK_ZONE_COND_IMP_OPEN:
 		/* Writes must be at the write pointer position */
-		if (blk_rq_pos(rq) != zone->wp) {
+		if (sector != zone->wp) {
 			cmd->error = BLK_STS_IOERR;
 			break;
 		}
@@ -126,7 +121,7 @@ void null_zone_write(struct nullb_cmd *cmd)
 		if (zone->cond == BLK_ZONE_COND_EMPTY)
 			zone->cond = BLK_ZONE_COND_IMP_OPEN;
 
-		zone->wp += rq_sectors;
+		zone->wp += nr_sectors;
 		if (zone->wp == zone->start + zone->len)
 			zone->cond = BLK_ZONE_COND_FULL;
 		break;
@@ -137,11 +132,10 @@ void null_zone_write(struct nullb_cmd *cmd)
 	}
 }
 
-void null_zone_reset(struct nullb_cmd *cmd)
+void null_zone_reset(struct nullb_cmd *cmd, sector_t sector)
 {
 	struct nullb_device *dev = cmd->nq->dev;
-	struct request *rq = cmd->rq;
-	unsigned int zno = null_zone_no(dev, blk_rq_pos(rq));
+	unsigned int zno = null_zone_no(dev, sector);
 	struct blk_zone *zone = &dev->zones[zno];
 
 	zone->cond = BLK_ZONE_COND_EMPTY;