Merge tag 'block-5.12-2021-03-27' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:

 - Fix regression from this merge window with the xarray partition
   change, which allowed partition counts that overflow the u8 that
   holds the partition number (Ming)

 - Fix zone append warning (Johannes)

 - Segmentation count fix for multipage bvecs (David)

 - Partition scan fix (Chris)

* tag 'block-5.12-2021-03-27' of git://git.kernel.dk/linux-block:
  block: don't create too many partitions
  block: support zone append bvecs
  block: recalculate segment count for multi-segment discards correctly
  block: clear GD_NEED_PART_SCAN later in bdev_disk_changed

block/bio.c

@@ -949,7 +949,7 @@ void bio_release_pages(struct bio *bio, bool mark_dirty)
 }
 EXPORT_SYMBOL_GPL(bio_release_pages);
 
-static int bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)
+static void __bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)
 {
 	WARN_ON_ONCE(bio->bi_max_vecs);
 
@@ -959,11 +959,26 @@ static int bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)
 	bio->bi_iter.bi_size = iter->count;
 	bio_set_flag(bio, BIO_NO_PAGE_REF);
 	bio_set_flag(bio, BIO_CLONED);
+}
 
+static int bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)
+{
+	__bio_iov_bvec_set(bio, iter);
 	iov_iter_advance(iter, iter->count);
 	return 0;
 }
 
+static int bio_iov_bvec_set_append(struct bio *bio, struct iov_iter *iter)
+{
+	struct request_queue *q = bio->bi_bdev->bd_disk->queue;
+	struct iov_iter i = *iter;
+
+	iov_iter_truncate(&i, queue_max_zone_append_sectors(q) << 9);
+	__bio_iov_bvec_set(bio, &i);
+	iov_iter_advance(iter, i.count);
+	return 0;
+}
+
 #define PAGE_PTRS_PER_BVEC     (sizeof(struct bio_vec) / sizeof(struct page *))
 
 /**
@@ -1094,8 +1109,8 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 	int ret = 0;
 
 	if (iov_iter_is_bvec(iter)) {
-		if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
-			return -EINVAL;
+		if (bio_op(bio) == REQ_OP_ZONE_APPEND)
+			return bio_iov_bvec_set_append(bio, iter);
 		return bio_iov_bvec_set(bio, iter);
 	}
 

block/blk-merge.c

@@ -382,6 +382,14 @@ unsigned int blk_recalc_rq_segments(struct request *rq)
 	switch (bio_op(rq->bio)) {
 	case REQ_OP_DISCARD:
 	case REQ_OP_SECURE_ERASE:
+		if (queue_max_discard_segments(rq->q) > 1) {
+			struct bio *bio = rq->bio;
+
+			for_each_bio(bio)
+				nr_phys_segs++;
+			return nr_phys_segs;
+		}
+		return 1;
 	case REQ_OP_WRITE_ZEROES:
 		return 0;
 	case REQ_OP_WRITE_SAME:

block/partitions/core.c

@@ -322,6 +322,13 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
 	const char *dname;
 	int err;
 
+	/*
+	 * disk_max_parts() won't be zero, either GENHD_FL_EXT_DEVT is set
+	 * or 'minors' is passed to alloc_disk().
+	 */
+	if (partno >= disk_max_parts(disk))
+		return ERR_PTR(-EINVAL);
+
 	/*
 	 * Partitions are not supported on zoned block devices that are used as
 	 * such.

fs/block_dev.c

@@ -1240,13 +1240,13 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 
 	lockdep_assert_held(&bdev->bd_mutex);
 
-	clear_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
-
 rescan:
 	ret = blk_drop_partitions(bdev);
 	if (ret)
 		return ret;
 
+	clear_bit(GD_NEED_PART_SCAN, &disk->state);
+
 	/*
 	 * Historically we only set the capacity to zero for devices that
 	 * support partitions (independ of actually having partitions created).