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>
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 0d62ad6..07ef936 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -55,7 +55,7 @@
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 @@
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 @@
}
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 @@
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 @@
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 @@
bio_pair_release(bp);
return 0;
}
- zone = find_zone(conf, sector);
+ sector_offset = sector;
+ zone = find_zone(conf, §or_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;
diff --git a/drivers/md/raid0.h b/drivers/md/raid0.h
index dbcf1da..124ba34 100644
--- a/drivers/md/raid0.h
+++ b/drivers/md/raid0.h
@@ -5,7 +5,6 @@
{
sector_t zone_end; /* Start of the next zone (in sectors) */
sector_t dev_start; /* Zone offset in real dev (in sectors) */
- sector_t sectors; /* Zone size in sectors */
int nb_dev; /* # of devices attached to the zone */
mdk_rdev_t **dev; /* Devices attached to the zone */
};
