staging: speakup_soft: Fix reading of init string

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

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 2b461b4..19cc761 100644 (file)
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -44,6 +44,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
        struct request_queue *q = bdev_get_queue(bdev);
        int type = REQ_WRITE | REQ_DISCARD;
        unsigned int max_discard_sectors;
+       unsigned int granularity, alignment, mask;
        struct bio_batch bb;
        struct bio *bio;
        int ret = 0;
@@ -54,18 +55,20 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
        if (!blk_queue_discard(q))
                return -EOPNOTSUPP;
 
+       /* Zero-sector (unknown) and one-sector granularities are the same.  */
+       granularity = max(q->limits.discard_granularity >> 9, 1U);
+       mask = granularity - 1;
+       alignment = (bdev_discard_alignment(bdev) >> 9) & mask;
+
        /*
         * Ensure that max_discard_sectors is of the proper
-        * granularity
+        * granularity, so that requests stay aligned after a split.
         */
        max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
+       max_discard_sectors = round_down(max_discard_sectors, granularity);
        if (unlikely(!max_discard_sectors)) {
                /* Avoid infinite loop below. Being cautious never hurts. */
                return -EOPNOTSUPP;
-       } else if (q->limits.discard_granularity) {
-               unsigned int disc_sects = q->limits.discard_granularity >> 9;
-
-               max_discard_sectors &= ~(disc_sects - 1);
        }
 
        if (flags & BLKDEV_DISCARD_SECURE) {
@@ -79,25 +82,37 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
        bb.wait = &wait;
 
        while (nr_sects) {
+               unsigned int req_sects;
+               sector_t end_sect;
+
                bio = bio_alloc(gfp_mask, 1);
                if (!bio) {
                        ret = -ENOMEM;
                        break;
                }
 
+               req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
+
+               /*
+                * If splitting a request, and the next starting sector would be
+                * misaligned, stop the discard at the previous aligned sector.
+                */
+               end_sect = sector + req_sects;
+               if (req_sects < nr_sects && (end_sect & mask) != alignment) {
+                       end_sect =
+                               round_down(end_sect - alignment, granularity)
+                               + alignment;
+                       req_sects = end_sect - sector;
+               }
+
                bio->bi_sector = sector;
                bio->bi_end_io = bio_batch_end_io;
                bio->bi_bdev = bdev;
                bio->bi_private = &bb;
 
-               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->bi_size = req_sects << 9;
+               nr_sects -= req_sects;
+               sector = end_sect;
 
                atomic_inc(&bb.done);
                submit_bio(type, bio);