Merge branch 'oprofile/core' into oprofile/x86

[sfrench/cifs-2.6.git] / drivers / md / dm-stripe.c

diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index d6e28d732b4d7de33e339ab32145634b6b170034..c297f6da91ea3cb1b05e4f35af21c0760ab25456 100644 (file)
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -25,6 +25,8 @@ struct stripe {
 
 struct stripe_c {
        uint32_t stripes;
+       int stripes_shift;
+       sector_t stripes_mask;
 
        /* The size of this target / num. stripes */
        sector_t stripe_width;
@@ -162,16 +164,22 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
        /* Set pointer to dm target; used in trigger_event */
        sc->ti = ti;
-
        sc->stripes = stripes;
        sc->stripe_width = width;
+
+       if (stripes & (stripes - 1))
+               sc->stripes_shift = -1;
+       else {
+               sc->stripes_shift = ffs(stripes) - 1;
+               sc->stripes_mask = ((sector_t) stripes) - 1;
+       }
+
        ti->split_io = chunk_size;
        ti->num_flush_requests = stripes;
+       ti->num_discard_requests = stripes;
 
+       sc->chunk_shift = ffs(chunk_size) - 1;
        sc->chunk_mask = ((sector_t) chunk_size) - 1;
-       for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
-               chunk_size >>= 1;
-       sc->chunk_shift--;
 
        /*
         * Get the stripe destinations.
@@ -207,26 +215,79 @@ static void stripe_dtr(struct dm_target *ti)
        kfree(sc);
 }
 
+static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
+                             uint32_t *stripe, sector_t *result)
+{
+       sector_t offset = dm_target_offset(sc->ti, sector);
+       sector_t chunk = offset >> sc->chunk_shift;
+
+       if (sc->stripes_shift < 0)
+               *stripe = sector_div(chunk, sc->stripes);
+       else {
+               *stripe = chunk & sc->stripes_mask;
+               chunk >>= sc->stripes_shift;
+       }
+
+       *result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask);
+}
+
+static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
+                                   uint32_t target_stripe, sector_t *result)
+{
+       uint32_t stripe;
+
+       stripe_map_sector(sc, sector, &stripe, result);
+       if (stripe == target_stripe)
+               return;
+       *result &= ~sc->chunk_mask;                     /* round down */
+       if (target_stripe < stripe)
+               *result += sc->chunk_mask + 1;          /* next chunk */
+}
+
+static int stripe_map_discard(struct stripe_c *sc, struct bio *bio,
+                             uint32_t target_stripe)
+{
+       sector_t begin, end;
+
+       stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
+       stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
+                               target_stripe, &end);
+       if (begin < end) {
+               bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
+               bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
+               bio->bi_size = to_bytes(end - begin);
+               return DM_MAPIO_REMAPPED;
+       } else {
+               /* The range doesn't map to the target stripe */
+               bio_endio(bio, 0);
+               return DM_MAPIO_SUBMITTED;
+       }
+}
+
 static int stripe_map(struct dm_target *ti, struct bio *bio,
                      union map_info *map_context)
 {
-       struct stripe_c *sc = (struct stripe_c *) ti->private;
-       sector_t offset, chunk;
+       struct stripe_c *sc = ti->private;
        uint32_t stripe;
+       unsigned target_request_nr;
 
        if (unlikely(bio_empty_barrier(bio))) {
-               BUG_ON(map_context->flush_request >= sc->stripes);
-               bio->bi_bdev = sc->stripe[map_context->flush_request].dev->bdev;
+               target_request_nr = map_context->target_request_nr;
+               BUG_ON(target_request_nr >= sc->stripes);
+               bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
                return DM_MAPIO_REMAPPED;
        }
+       if (unlikely(bio->bi_rw & REQ_DISCARD)) {
+               target_request_nr = map_context->target_request_nr;
+               BUG_ON(target_request_nr >= sc->stripes);
+               return stripe_map_discard(sc, bio, target_request_nr);
+       }
 
-       offset = bio->bi_sector - ti->begin;
-       chunk = offset >> sc->chunk_shift;
-       stripe = sector_div(chunk, sc->stripes);
+       stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
 
+       bio->bi_sector += sc->stripe[stripe].physical_start;
        bio->bi_bdev = sc->stripe[stripe].dev->bdev;
-       bio->bi_sector = sc->stripe[stripe].physical_start +
-           (chunk << sc->chunk_shift) + (offset & sc->chunk_mask);
+
        return DM_MAPIO_REMAPPED;
 }