block: add async variant of blkdev_issue_zeroout

Similar to __blkdev_issue_discard this variant allows submitting
the final bio asynchronously and chaining multiple ranges
into a single completion.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 18abda862915ab735038e98467f1c0fa8186aefb..bfb28b03765ee372ac69b4dc7c721e3f7222d7a2 100644 (file)
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -137,24 +137,24 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 EXPORT_SYMBOL(blkdev_issue_discard);
 
 /**
- * blkdev_issue_write_same - queue a write same operation
+ * __blkdev_issue_write_same - generate number of bios with same page
  * @bdev:      target blockdev
  * @sector:    start sector
  * @nr_sects:  number of sectors to write
  * @gfp_mask:  memory allocation flags (for bio_alloc)
  * @page:      page containing data to write
+ * @biop:      pointer to anchor bio
  *
  * Description:
- *    Issue a write same request for the sectors in question.
+ *  Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
  */
-int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
-                           sector_t nr_sects, gfp_t gfp_mask,
-                           struct page *page)
+static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
+               sector_t nr_sects, gfp_t gfp_mask, struct page *page,
+               struct bio **biop)
 {
        struct request_queue *q = bdev_get_queue(bdev);
        unsigned int max_write_same_sectors;
-       struct bio *bio = NULL;
-       int ret = 0;
+       struct bio *bio = *biop;
        sector_t bs_mask;
 
        if (!q)
@@ -164,6 +164,9 @@ int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
        if ((sector | nr_sects) & bs_mask)
                return -EINVAL;
 
+       if (!bdev_write_same(bdev))
+               return -EOPNOTSUPP;
+
        /* Ensure that max_write_same_sectors doesn't overflow bi_size */
        max_write_same_sectors = UINT_MAX >> 9;
 
@@ -185,32 +188,63 @@ int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
                        bio->bi_iter.bi_size = nr_sects << 9;
                        nr_sects = 0;
                }
+               cond_resched();
        }
 
-       if (bio) {
+       *biop = bio;
+       return 0;
+}
+
+/**
+ * blkdev_issue_write_same - queue a write same operation
+ * @bdev:      target blockdev
+ * @sector:    start sector
+ * @nr_sects:  number of sectors to write
+ * @gfp_mask:  memory allocation flags (for bio_alloc)
+ * @page:      page containing data
+ *
+ * Description:
+ *    Issue a write same request for the sectors in question.
+ */
+int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
+                               sector_t nr_sects, gfp_t gfp_mask,
+                               struct page *page)
+{
+       struct bio *bio = NULL;
+       struct blk_plug plug;
+       int ret;
+
+       blk_start_plug(&plug);
+       ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
+                       &bio);
+       if (ret == 0 && bio) {
                ret = submit_bio_wait(bio);
                bio_put(bio);
        }
+       blk_finish_plug(&plug);
        return ret;
 }
 EXPORT_SYMBOL(blkdev_issue_write_same);
 
 /**
- * blkdev_issue_zeroout - generate number of zero filed write bios
+ * __blkdev_issue_zeroout - generate number of zero filed write bios
  * @bdev:      blockdev to issue
  * @sector:    start sector
  * @nr_sects:  number of sectors to write
  * @gfp_mask:  memory allocation flags (for bio_alloc)
+ * @biop:      pointer to anchor bio
+ * @discard:   discard flag
  *
  * Description:
  *  Generate and issue number of bios with zerofiled pages.
  */
-
-static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
-                                 sector_t nr_sects, gfp_t gfp_mask)
+int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+               sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
+               bool discard)
 {
        int ret;
-       struct bio *bio = NULL;
+       int bi_size = 0;
+       struct bio *bio = *biop;
        unsigned int sz;
        sector_t bs_mask;
 
@@ -218,6 +252,19 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
        if ((sector | nr_sects) & bs_mask)
                return -EINVAL;
 
+       if (discard) {
+               ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask,
+                               BLKDEV_DISCARD_ZERO, biop);
+               if (ret == 0 || (ret && ret != -EOPNOTSUPP))
+                       goto out;
+       }
+
+       ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
+                       ZERO_PAGE(0), biop);
+       if (ret == 0 || (ret && ret != -EOPNOTSUPP))
+               goto out;
+
+       ret = 0;
        while (nr_sects != 0) {
                bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES),
                                gfp_mask);
@@ -227,21 +274,20 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 
                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))
+                       bi_size = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
+                       nr_sects -= bi_size >> 9;
+                       sector += bi_size >> 9;
+                       if (bi_size < (sz << 9))
                                break;
                }
+               cond_resched();
        }
 
-       if (bio) {
-               ret = submit_bio_wait(bio);
-               bio_put(bio);
-               return ret;
-       }
-       return 0;
+       *biop = bio;
+out:
+       return ret;
 }
+EXPORT_SYMBOL(__blkdev_issue_zeroout);
 
 /**
  * blkdev_issue_zeroout - zero-fill a block range
@@ -263,21 +309,22 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
  *  clearing the block range. Otherwise the zeroing will be performed
  *  using regular WRITE calls.
  */
-
 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
                         sector_t nr_sects, gfp_t gfp_mask, bool discard)
 {
-       if (discard) {
-               if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask,
-                               BLKDEV_DISCARD_ZERO))
-                       return 0;
-       }
+       int ret;
+       struct bio *bio = NULL;
+       struct blk_plug plug;
 
-       if (bdev_write_same(bdev) &&
-           blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
-                                   ZERO_PAGE(0)) == 0)
-               return 0;
+       blk_start_plug(&plug);
+       ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask,
+                       &bio, discard);
+       if (ret == 0 && bio) {
+               ret = submit_bio_wait(bio);
+               bio_put(bio);
+       }
+       blk_finish_plug(&plug);
 
-       return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
+       return ret;
 }
 EXPORT_SYMBOL(blkdev_issue_zeroout);

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 541fdd8787a5b67c6febf5560d073d4ab1bca335..7e9d8a0895beb7b47d82a610285920d635f79557 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1269,6 +1269,9 @@ extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
                struct bio **biop);
 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
                sector_t nr_sects, gfp_t gfp_mask, struct page *page);
+extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+               sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
+               bool discard);
 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
                sector_t nr_sects, gfp_t gfp_mask, bool discard);
 static inline int sb_issue_discard(struct super_block *sb, sector_t block,