md-multipath: stop using bio_devname

Use the %pg format specifier to save on stack consuption and code size.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220304180105.409765-7-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/md-multipath.c

@@ -297,7 +297,6 @@ static void multipathd(struct md_thread *thread)
 
 	md_check_recovery(mddev);
 	for (;;) {
-		char b[BDEVNAME_SIZE];
 		spin_lock_irqsave(&conf->device_lock, flags);
 		if (list_empty(head))
 			break;
@@ -309,13 +308,13 @@ static void multipathd(struct md_thread *thread)
 		bio->bi_iter.bi_sector = mp_bh->master_bio->bi_iter.bi_sector;
 
 		if ((mp_bh->path = multipath_map (conf))<0) {
-			pr_err("multipath: %s: unrecoverable IO read error for block %llu\n",
-			       bio_devname(bio, b),
+			pr_err("multipath: %pg: unrecoverable IO read error for block %llu\n",
+			       bio->bi_bdev,
 			       (unsigned long long)bio->bi_iter.bi_sector);
 			multipath_end_bh_io(mp_bh, BLK_STS_IOERR);
 		} else {
-			pr_err("multipath: %s: redirecting sector %llu to another IO path\n",
-			       bio_devname(bio, b),
+			pr_err("multipath: %pg: redirecting sector %llu to another IO path\n",
+			       bio->bi_bdev,
 			       (unsigned long long)bio->bi_iter.bi_sector);
 			*bio = *(mp_bh->master_bio);
 			bio->bi_iter.bi_sector +=