block: discard granularity might not be power of 2
[linux-3.10.git] / block / blk-lib.c
index 9373b58..5677fd3 100644 (file)
@@ -43,8 +43,8 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
        DECLARE_COMPLETION_ONSTACK(wait);
        struct request_queue *q = bdev_get_queue(bdev);
        int type = REQ_WRITE | REQ_DISCARD;
-       unsigned int max_discard_sectors;
-       unsigned int granularity, alignment, mask;
+       sector_t max_discard_sectors;
+       sector_t granularity, alignment;
        struct bio_batch bb;
        struct bio *bio;
        int ret = 0;
@@ -57,15 +57,16 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 
        /* 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;
+       alignment = bdev_discard_alignment(bdev) >> 9;
+       alignment = sector_div(alignment, granularity);
 
        /*
         * Ensure that max_discard_sectors is of the proper
         * 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);
+       sector_div(max_discard_sectors, granularity);
+       max_discard_sectors *= granularity;
        if (unlikely(!max_discard_sectors)) {
                /* Avoid infinite loop below. Being cautious never hurts. */
                return -EOPNOTSUPP;
@@ -83,7 +84,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 
        while (nr_sects) {
                unsigned int req_sects;
-               sector_t end_sect;
+               sector_t end_sect, tmp;
 
                bio = bio_alloc(gfp_mask, 1);
                if (!bio) {
@@ -98,10 +99,12 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
                 * 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;
+               tmp = end_sect;
+               if (req_sects < nr_sects &&
+                   sector_div(tmp, granularity) != alignment) {
+                       end_sect = end_sect - alignment;
+                       sector_div(end_sect, granularity);
+                       end_sect = end_sect * granularity + alignment;
                        req_sects = end_sect - sector;
                }