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authorDmitry Monakhov <dmonakhov@openvz.org>2010-04-28 17:55:08 +0400
committerJens Axboe <jens.axboe@oracle.com>2010-04-28 19:47:36 +0200
commitf31e7e4022841c43c53b847b86b1bf97a08b2c94 (patch)
tree738821236a4e84f790d597bb2cc04bd812668b6a /block/blk-lib.c
parentf17e232e9237c231daf9f0f4b177c61218bcb2e4 (diff)
downloadlinux-linaro-stable-f31e7e4022841c43c53b847b86b1bf97a08b2c94.tar.gz
blkdev: move blkdev_issue helper functions to separate file
Move blkdev_issue_discard from blk-barrier.c because it is not barrier related. Later the file will be populated by other helpers. Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-lib.c')
-rw-r--r--block/blk-lib.c114
1 files changed, 114 insertions, 0 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
new file mode 100644
index 000000000000..0dc438812d81
--- /dev/null
+++ b/block/blk-lib.c
@@ -0,0 +1,114 @@
+/*
+ * Functions related to generic helpers functions
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/scatterlist.h>
+
+#include "blk.h"
+
+static void blkdev_discard_end_io(struct bio *bio, int err)
+{
+ if (err) {
+ if (err == -EOPNOTSUPP)
+ set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
+ clear_bit(BIO_UPTODATE, &bio->bi_flags);
+ }
+
+ if (bio->bi_private)
+ complete(bio->bi_private);
+ __free_page(bio_page(bio));
+
+ bio_put(bio);
+}
+
+/**
+ * blkdev_issue_discard - queue a discard
+ * @bdev: blockdev to issue discard for
+ * @sector: start sector
+ * @nr_sects: number of sectors to discard
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ * @flags: BLKDEV_IFL_* flags to control behaviour
+ *
+ * Description:
+ * Issue a discard request for the sectors in question.
+ */
+int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
+{
+ DECLARE_COMPLETION_ONSTACK(wait);
+ struct request_queue *q = bdev_get_queue(bdev);
+ int type = flags & BLKDEV_IFL_BARRIER ?
+ DISCARD_BARRIER : DISCARD_NOBARRIER;
+ struct bio *bio;
+ struct page *page;
+ int ret = 0;
+
+ if (!q)
+ return -ENXIO;
+
+ if (!blk_queue_discard(q))
+ return -EOPNOTSUPP;
+
+ while (nr_sects && !ret) {
+ unsigned int sector_size = q->limits.logical_block_size;
+ unsigned int max_discard_sectors =
+ min(q->limits.max_discard_sectors, UINT_MAX >> 9);
+
+ bio = bio_alloc(gfp_mask, 1);
+ if (!bio)
+ goto out;
+ bio->bi_sector = sector;
+ bio->bi_end_io = blkdev_discard_end_io;
+ bio->bi_bdev = bdev;
+ if (flags & BLKDEV_IFL_WAIT)
+ bio->bi_private = &wait;
+
+ /*
+ * Add a zeroed one-sector payload as that's what
+ * our current implementations need. If we'll ever need
+ * more the interface will need revisiting.
+ */
+ page = alloc_page(gfp_mask | __GFP_ZERO);
+ if (!page)
+ goto out_free_bio;
+ if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size)
+ goto out_free_page;
+
+ /*
+ * And override the bio size - the way discard works we
+ * touch many more blocks on disk than the actual payload
+ * length.
+ */
+ if (nr_sects > max_discard_sectors) {
+ bio->bi_size = max_discard_sectors << 9;
+ nr_sects -= max_discard_sectors;
+ sector += max_discard_sectors;
+ } else {
+ bio->bi_size = nr_sects << 9;
+ nr_sects = 0;
+ }
+
+ bio_get(bio);
+ submit_bio(type, bio);
+
+ if (flags & BLKDEV_IFL_WAIT)
+ wait_for_completion(&wait);
+
+ if (bio_flagged(bio, BIO_EOPNOTSUPP))
+ ret = -EOPNOTSUPP;
+ else if (!bio_flagged(bio, BIO_UPTODATE))
+ ret = -EIO;
+ bio_put(bio);
+ }
+ return ret;
+out_free_page:
+ __free_page(page);
+out_free_bio:
+ bio_put(bio);
+out:
+ return -ENOMEM;
+}
+EXPORT_SYMBOL(blkdev_issue_discard);