Merge branch 'net-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vxy/lksctp-dev

[safe/jmp/linux-2.6] / block / blk-barrier.c

diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 6593ab3..6d88544 100644 (file)
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -5,6 +5,7 @@
 #include <linux/module.h>
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <linux/gfp.h>
 
 #include "blk.h"
 
@@ -350,6 +351,7 @@ static void blkdev_discard_end_io(struct bio *bio, int err)
 
        if (bio->bi_private)
                complete(bio->bi_private);
+       __free_page(bio_page(bio));
 
        bio_put(bio);
 }
@@ -372,30 +374,50 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
        struct request_queue *q = bdev_get_queue(bdev);
        int type = flags & DISCARD_FL_BARRIER ?
                DISCARD_BARRIER : DISCARD_NOBARRIER;
+       struct bio *bio;
+       struct page *page;
        int ret = 0;
 
        if (!q)
                return -ENXIO;
 
-       if (!q->prepare_discard_fn)
+       if (!blk_queue_discard(q))
                return -EOPNOTSUPP;
 
        while (nr_sects && !ret) {
-               struct bio *bio = bio_alloc(gfp_mask, 0);
-               if (!bio)
-                       return -ENOMEM;
+               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 & DISCARD_FL_WAIT)
                        bio->bi_private = &wait;
 
-               bio->bi_sector = sector;
+               /*
+                * 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;
 
-               if (nr_sects > queue_max_hw_sectors(q)) {
-                       bio->bi_size = queue_max_hw_sectors(q) << 9;
-                       nr_sects -= queue_max_hw_sectors(q);
-                       sector += queue_max_hw_sectors(q);
+               /*
+                * 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;
@@ -414,5 +436,11 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
                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);