[dm-devel] [PATCH 2/6] block: Introduce bio_add_zero_pages()
Bart Van Assche
bart.vanassche at sandisk.com
Thu Dec 17 11:40:15 UTC 2015
Move the code for adding one or more zero pages into a new function.
Signed-off-by: Bart Van Assche <bart.vanassche at sandisk.com>
Cc: Jan Kara <jack at suse.cz>
Cc: Christoph Hellwig <hch at lst.de>
Cc: Mike Snitzer <snitzer at redhat.com>
Cc: Martin K. Petersen <martin.petersen at oracle.com>
Cc: Dmitry Monakhov <dmonakhov at openvz.org>
---
block/blk-lib.c | 30 +++++++++++++++++++-----------
1 file changed, 19 insertions(+), 11 deletions(-)
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 2f4c6b2..f44ec95 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -219,6 +219,22 @@ int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
}
EXPORT_SYMBOL(blkdev_issue_write_same);
+static void bio_add_zero_pages(struct bio *bio, sector_t nr_sects)
+{
+ unsigned sz;
+ int ret;
+
+ /* Avoid that bi_size overflows */
+ nr_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
+
+ for (; nr_sects != 0; nr_sects -= ret >> 9) {
+ sz = min_t(unsigned, PAGE_SIZE >> 9, nr_sects) << 9;
+ ret = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
+ if (ret < sz)
+ break;
+ }
+}
+
/**
* blkdev_issue_zeroout - generate number of zero filed write bios
* @bdev: blockdev to issue
@@ -236,7 +252,6 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
int ret;
struct bio *bio;
struct bio_batch bb;
- unsigned int sz;
DECLARE_COMPLETION_ONSTACK(wait);
atomic_set(&bb.done, 1);
@@ -256,16 +271,9 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
bio->bi_bdev = bdev;
bio->bi_end_io = bio_batch_end_io;
bio->bi_private = &bb;
-
- while (nr_sects != 0) {
- sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
- ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
- nr_sects -= ret >> 9;
- sector += ret >> 9;
- if (ret < (sz << 9))
- break;
- }
- ret = 0;
+ bio_add_zero_pages(bio, nr_sects);
+ nr_sects -= bio->bi_iter.bi_size >> 9;
+ sector += bio->bi_iter.bi_size >> 9;
atomic_inc(&bb.done);
submit_bio(WRITE, bio);
}
--
2.1.4
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