[PATCH 03/10] block: add a blk_alloc_secure_erase_bio helper

[Christoph Hellwig <hch@xxxxxx>]

Factor out a helper from blkdev_issue_secure_erase that chews off as much
as possible from a secure_erase range and allocates a bio for it.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 block/blk-lib.c     | 36 +++++++++++++++++++++++-------------
 include/linux/bio.h |  2 ++
 2 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index ff12c3d2de5aae..cf4f0ee6b14503 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -293,26 +293,36 @@ static sector_t bio_secure_erase_limit(struct block_device *bdev)
 		(UINT_MAX >> SECTOR_SHIFT) & ~bs_mask);
 }
 
+struct bio *blk_alloc_secure_erase_bio(struct block_device *bdev,
+		sector_t *sector, sector_t *nr_sects, gfp_t gfp)
+{
+	sector_t bio_sects = min(*nr_sects, bio_secure_erase_limit(bdev));
+	struct bio *bio;
+
+	if (!bio_sects)
+		return NULL;
+	bio = bio_alloc(bdev, 0, REQ_OP_SECURE_ERASE, gfp);
+	if (!bio)
+		return NULL;
+	bio->bi_iter.bi_sector = *sector;
+	bio->bi_iter.bi_size = bio_sects << SECTOR_SHIFT;
+	*sector += bio_sects;
+	*nr_sects -= bio_sects;
+	cond_resched();
+	return bio;
+}
+
 int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp)
 {
-	unsigned int max_sectors = bio_secure_erase_limit(bdev);
-	struct bio *bio = NULL;
+	struct bio *bio = NULL, *next;
 	struct blk_plug plug;
 	int ret = 0;
 
 	blk_start_plug(&plug);
-	while (nr_sects) {
-		unsigned int len = min_t(sector_t, nr_sects, max_sectors);
-
-		bio = blk_next_bio(bio, bdev, 0, REQ_OP_SECURE_ERASE, gfp);
-		bio->bi_iter.bi_sector = sector;
-		bio->bi_iter.bi_size = len << SECTOR_SHIFT;
-
-		sector += len;
-		nr_sects -= len;
-		cond_resched();
-	}
+	while ((next = blk_alloc_secure_erase_bio(bdev, &sector, &nr_sects,
+			gfp)))
+		bio = bio_chain_and_submit(bio, next);
 	if (bio) {
 		ret = submit_bio_wait(bio);
 		bio_put(bio);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index d5379548d684e1..e1da5fe49baca1 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -835,5 +835,7 @@ struct bio *bio_chain_and_submit(struct bio *prev, struct bio *new);
 
 struct bio *blk_alloc_discard_bio(struct block_device *bdev,
 		sector_t *sector, sector_t *nr_sects, gfp_t gfp_mask);
+struct bio *blk_alloc_secure_erase_bio(struct block_device *bdev,
+		sector_t *sector, sector_t *nr_sects, gfp_t gfp);
 
 #endif /* __LINUX_BIO_H */
-- 
2.43.0