Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[pandora-kernel.git] / block / blk-lib.c

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 19cc761..9373b58 100644 (file)
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -129,6 +129,80 @@ 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
+ * @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
+ *
+ * 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)
+{
+       DECLARE_COMPLETION_ONSTACK(wait);
+       struct request_queue *q = bdev_get_queue(bdev);
+       unsigned int max_write_same_sectors;
+       struct bio_batch bb;
+       struct bio *bio;
+       int ret = 0;
+
+       if (!q)
+               return -ENXIO;
+
+       max_write_same_sectors = q->limits.max_write_same_sectors;
+
+       if (max_write_same_sectors == 0)
+               return -EOPNOTSUPP;
+
+       atomic_set(&bb.done, 1);
+       bb.flags = 1 << BIO_UPTODATE;
+       bb.wait = &wait;
+
+       while (nr_sects) {
+               bio = bio_alloc(gfp_mask, 1);
+               if (!bio) {
+                       ret = -ENOMEM;
+                       break;
+               }
+
+               bio->bi_sector = sector;
+               bio->bi_end_io = bio_batch_end_io;
+               bio->bi_bdev = bdev;
+               bio->bi_private = &bb;
+               bio->bi_vcnt = 1;
+               bio->bi_io_vec->bv_page = page;
+               bio->bi_io_vec->bv_offset = 0;
+               bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
+
+               if (nr_sects > max_write_same_sectors) {
+                       bio->bi_size = max_write_same_sectors << 9;
+                       nr_sects -= max_write_same_sectors;
+                       sector += max_write_same_sectors;
+               } else {
+                       bio->bi_size = nr_sects << 9;
+                       nr_sects = 0;
+               }
+
+               atomic_inc(&bb.done);
+               submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
+       }
+
+       /* Wait for bios in-flight */
+       if (!atomic_dec_and_test(&bb.done))
+               wait_for_completion(&wait);
+
+       if (!test_bit(BIO_UPTODATE, &bb.flags))
+               ret = -ENOTSUPP;
+
+       return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_write_same);
+
 /**
  * blkdev_issue_zeroout - generate number of zero filed write bios
  * @bdev:      blockdev to issue
@@ -140,7 +214,7 @@ EXPORT_SYMBOL(blkdev_issue_discard);
  *  Generate and issue number of bios with zerofiled pages.
  */
 
-int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
                        sector_t nr_sects, gfp_t gfp_mask)
 {
        int ret;
@@ -190,4 +264,32 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 
        return ret;
 }
+
+/**
+ * blkdev_issue_zeroout - zero-fill a block range
+ * @bdev:      blockdev to write
+ * @sector:    start sector
+ * @nr_sects:  number of sectors to write
+ * @gfp_mask:  memory allocation flags (for bio_alloc)
+ *
+ * Description:
+ *  Generate and issue number of bios with zerofiled pages.
+ */
+
+int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+                        sector_t nr_sects, gfp_t gfp_mask)
+{
+       if (bdev_write_same(bdev)) {
+               unsigned char bdn[BDEVNAME_SIZE];
+
+               if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
+                                            ZERO_PAGE(0)))
+                       return 0;
+
+               bdevname(bdev, bdn);
+               pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
+       }
+
+       return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
+}
 EXPORT_SYMBOL(blkdev_issue_zeroout);