[PATCH 02/10] block: factor out a bio_secure_erase_limit helper

[Christoph Hellwig <hch@lst.de>]

Add a helper to size the maximum secure erase bio without exceeding the
queue limit or overlowing the bi_size member.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-lib.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 4aabfc4a7eaa20..ff12c3d2de5aae 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -285,20 +285,22 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 }
 EXPORT_SYMBOL(blkdev_issue_zeroout);
 
+static sector_t bio_secure_erase_limit(struct block_device *bdev)
+{
+	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
+
+	return min(bdev_max_secure_erase_sectors(bdev),
+		(UINT_MAX >> SECTOR_SHIFT) & ~bs_mask);
+}
+
 int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp)
 {
-	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
-	unsigned int max_sectors = bdev_max_secure_erase_sectors(bdev);
+	unsigned int max_sectors = bio_secure_erase_limit(bdev);
 	struct bio *bio = NULL;
 	struct blk_plug plug;
 	int ret = 0;
 
-	/* make sure that "len << SECTOR_SHIFT" doesn't overflow */
-	if (max_sectors > UINT_MAX >> SECTOR_SHIFT)
-		max_sectors = UINT_MAX >> SECTOR_SHIFT;
-	max_sectors &= ~bs_mask;
-
 	blk_start_plug(&plug);
 	while (nr_sects) {
 		unsigned int len = min_t(sector_t, nr_sects, max_sectors);
-- 
2.43.0