[RFC 2/3] block: use LARGE_ZERO_PAGE in __blkdev_issue_zero_pages()

[Pankaj Raghav <p.raghav@samsung.com>]

Use LARGE_ZERO_PAGE in __blkdev_issue_zero_pages() instead of ZERO_PAGE.
On systems that support LARGE_ZERO_PAGE, we will end up sending larger
bvecs instead of multiple small ones.

Noticed a 4% increase in performance on a commercial NVMe SSD which does
not support OP_WRITE_ZEROES. The performance gains might be bigger if
the device supports larger MDTS.

Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 block/blk-lib.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 4c9f20a689f7..80dfc737d1f6 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -211,8 +211,8 @@ static void __blkdev_issue_zero_pages(struct block_device *bdev,
 			unsigned int len, added;
 
 			len = min_t(sector_t,
-				PAGE_SIZE, nr_sects << SECTOR_SHIFT);
-			added = bio_add_page(bio, ZERO_PAGE(0), len, 0);
+				ZERO_LARGE_PAGE_SIZE, nr_sects << SECTOR_SHIFT);
+			added = bio_add_page(bio, ZERO_LARGE_PAGE(0), len, 0);
 			if (added < len)
 				break;
 			nr_sects -= added >> SECTOR_SHIFT;
-- 
2.47.2