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authorNeilBrown <neilb@suse.de>2009-06-16 16:50:35 +1000
committerNeilBrown <neilb@suse.de>2009-06-16 16:50:35 +1000
commit49f357a22b3fa3eeac042dfa0a6cae920c174e48 (patch)
tree55d90a158e990ea38c2487167c3d9a4f7f7943cf /drivers/md/raid0.c
parentfb5ab4b5d6e16fd5006c9f800d0116f3547cb760 (diff)
md: raid0: remove ->sectors from the strip_zone structure.
storing ->sectors is redundant as is can be computed from the difference z->zone_end - (z-1)->zone_end The one place where it is used, it is just as efficient to use a zone_end value instead. And removing it makes strip_zone smaller, so they array of these that is searched on every request has a better chance to say in cache. So discard the field and get the value from elsewhere. Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md/raid0.c')
-rw-r--r--drivers/md/raid0.c33
1 files changed, 19 insertions, 14 deletions
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 0d62ad6df21..07ef936afc7 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -55,7 +55,7 @@ static int raid0_congested(void *data, int bits)
static int create_strip_zones(mddev_t *mddev)
{
int i, c, j, err;
- sector_t curr_zone_end;
+ sector_t curr_zone_end, sectors;
mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;
struct strip_zone *zone;
int cnt;
@@ -153,10 +153,9 @@ static int create_strip_zones(mddev_t *mddev)
goto abort;
}
zone->nb_dev = cnt;
- zone->sectors = smallest->sectors * cnt;
- zone->zone_end = zone->sectors;
+ zone->zone_end = smallest->sectors * cnt;
- curr_zone_end = zone->sectors;
+ curr_zone_end = zone->zone_end;
/* now do the other zones */
for (i = 1; i < conf->nr_strip_zones; i++)
@@ -189,11 +188,11 @@ static int create_strip_zones(mddev_t *mddev)
}
zone->nb_dev = c;
- zone->sectors = (smallest->sectors - zone->dev_start) * c;
+ sectors = (smallest->sectors - zone->dev_start) * c;
printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n",
- zone->nb_dev, (unsigned long long)zone->sectors);
+ zone->nb_dev, (unsigned long long)sectors);
- curr_zone_end += zone->sectors;
+ curr_zone_end += sectors;
zone->zone_end = curr_zone_end;
printk(KERN_INFO "raid0: current zone start: %llu\n",
@@ -310,16 +309,22 @@ static int raid0_stop(mddev_t *mddev)
return 0;
}
-/* Find the zone which holds a particular offset */
+/* Find the zone which holds a particular offset
+ * Update *sectorp to be an offset in that zone
+ */
static struct strip_zone *find_zone(struct raid0_private_data *conf,
- sector_t sector)
+ sector_t *sectorp)
{
int i;
struct strip_zone *z = conf->strip_zone;
+ sector_t sector = *sectorp;
for (i = 0; i < conf->nr_strip_zones; i++)
- if (sector < z[i].zone_end)
+ if (sector < z[i].zone_end) {
+ if (i)
+ *sectorp = sector - z[i-1].zone_end;
return z + i;
+ }
BUG();
}
@@ -331,7 +336,7 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio)
struct strip_zone *zone;
mdk_rdev_t *tmp_dev;
sector_t chunk;
- sector_t sector, rsect;
+ sector_t sector, rsect, sector_offset;
const int rw = bio_data_dir(bio);
int cpu;
@@ -368,11 +373,11 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio)
bio_pair_release(bp);
return 0;
}
- zone = find_zone(conf, sector);
+ sector_offset = sector;
+ zone = find_zone(conf, &sector_offset);
sect_in_chunk = bio->bi_sector & (chunk_sects - 1);
{
- sector_t x = (zone->sectors + sector - zone->zone_end)
- >> chunksect_bits;
+ sector_t x = sector_offset >> chunksect_bits;
sector_div(x, zone->nb_dev);
chunk = x;