Merge tag 'block-6.16-20250614' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:

 - Fix for a deadlock on queue freeze with zoned writes

 - Fix for zoned append emulation

 - Two bio folio fixes, for sparsemem and for very large folios

 - Fix for a performance regression introduced in 6.13 when plug
   insertion was changed

 - Fix for NVMe passthrough handling for polled IO

 - Document the ublk auto registration feature

 - loop lockdep warning fix

* tag 'block-6.16-20250614' of git://git.kernel.dk/linux:
  nvme: always punt polled uring_cmd end_io work to task_work
  Documentation: ublk: Separate UBLK_F_AUTO_BUF_REG fallback behavior sublists
  block: Fix bvec_set_folio() for very large folios
  bio: Fix bio_first_folio() for SPARSEMEM without VMEMMAP
  block: use plug request list tail for one-shot backmerge attempt
  block: don't use submit_bio_noacct_nocheck in blk_zone_wplug_bio_work
  block: Clear BIO_EMULATES_ZONE_APPEND flag on BIO completion
  ublk: document auto buffer registration(UBLK_F_AUTO_BUF_REG)
  loop: move lo_set_size() out of queue freeze

2 files changed, 19 insertions, 15 deletions

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 3af1d284add5..70d704615be5 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -998,20 +998,20 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
 	if (!plug || rq_list_empty(&plug->mq_list))
 		return false;
 
-	rq_list_for_each(&plug->mq_list, rq) {
-		if (rq->q == q) {
-			if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) ==
-			    BIO_MERGE_OK)
-				return true;
-			break;
-		}
+	rq = plug->mq_list.tail;
+	if (rq->q == q)
+		return blk_attempt_bio_merge(q, rq, bio, nr_segs, false) ==
+			BIO_MERGE_OK;
+	else if (!plug->multiple_queues)
+		return false;
 
-		/*
-		 * Only keep iterating plug list for merges if we have multiple
-		 * queues
-		 */
-		if (!plug->multiple_queues)
-			break;
+	rq_list_for_each(&plug->mq_list, rq) {
+		if (rq->q != q)
+			continue;
+		if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) ==
+		    BIO_MERGE_OK)
+			return true;
+		break;
 	}
 	return false;
 }
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 8f15d1aa6eb8..351d659280e1 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -1225,6 +1225,7 @@ void blk_zone_write_plug_bio_endio(struct bio *bio)
 	if (bio_flagged(bio, BIO_EMULATES_ZONE_APPEND)) {
 		bio->bi_opf &= ~REQ_OP_MASK;
 		bio->bi_opf |= REQ_OP_ZONE_APPEND;
+		bio_clear_flag(bio, BIO_EMULATES_ZONE_APPEND);
 	}
 
 	/*
@@ -1306,7 +1307,6 @@ again:
 	spin_unlock_irqrestore(&zwplug->lock, flags);
 
 	bdev = bio->bi_bdev;
-	submit_bio_noacct_nocheck(bio);
 
 	/*
 	 * blk-mq devices will reuse the extra reference on the request queue
@@ -1314,8 +1314,12 @@ again:
 	 * path for BIO-based devices will not do that. So drop this extra
 	 * reference here.
 	 */
-	if (bdev_test_flag(bdev, BD_HAS_SUBMIT_BIO))
+	if (bdev_test_flag(bdev, BD_HAS_SUBMIT_BIO)) {
+		bdev->bd_disk->fops->submit_bio(bio);
 		blk_queue_exit(bdev->bd_disk->queue);
+	} else {
+		blk_mq_submit_bio(bio);
+	}
 
 put_zwplug:
 	/* Drop the reference we took in disk_zone_wplug_schedule_bio_work(). */