[PATCH] md: raid0: Remove hash spacing and sector shift.

Andre Noll
2009-05-14T10:43:50Z

The "sector_shift" and "spacing" fields of struct raid0_private_data
were only used for the hash table lookups. So the removal of the
hash table allows get rid of these fields as well which simplifies
create_strip_zones() and raid0_run() quite a bit.

Signed-off-by: Andre Noll <maan@systemlinux.org>
---
drivers/md/raid0.c | 63 +---------------------------------------------------
drivers/md/raid0.h | 3 --
2 files changed, 1 insertions(+), 65 deletions(-)

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 6bae90c..2401e94 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -57,7 +57,6 @@ static int create_strip_zones (mddev_t *mddev)
{
int i, c, j;
sector_t current_start, curr_zone_start;
- sector_t min_spacing;
raid0_conf_t *conf = mddev_to_conf(mddev);
mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;
struct strip_zone *zone;
@@ -206,28 +205,7 @@ static int create_strip_zones (mddev_t *mddev)
(unsigned long long)current_start);
}

- /* Now find appropriate hash spacing.
- * We want a number which causes most hash entries to cover
- * at most two strips, but the hash table must be at most
- * 1 PAGE. We choose the smallest strip, or contiguous collection
- * of strips, that has big enough size. We never consider the last
- * strip though as it's size has no bearing on the efficacy of the hash
- * table.
- */
- conf->spacing = curr_zone_start;
- min_spacing = curr_zone_start;
- sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*));
- for (i=0; i < conf->nr_strip_zones-1; i++) {
- sector_t s = 0;
- for (j = i; j < conf->nr_strip_zones - 1 &&
- s < min_spacing; j++)
- s += conf->strip_zone[j].sectors;
- if (s >= min_spacing && s < conf->spacing)
- conf->spacing = s;
- }
-
mddev->queue->unplug_fn = raid0_unplug;
-
mddev->queue->backing_dev_info.congested_fn = raid0_congested;
mddev->queue->backing_dev_info.congested_data = mddev;

@@ -277,10 +255,8 @@ static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks)
return array_sectors;
}

-static int raid0_run (mddev_t *mddev)
+static int raid0_run(mddev_t *mddev)
{
- unsigned cur=0, i=0, nb_zone;
- s64 sectors;
raid0_conf_t *conf;

if (mddev->chunk_size == 0) {
@@ -310,43 +286,6 @@ static int raid0_run (mddev_t *mddev)

printk(KERN_INFO "raid0 : md_size is %llu sectors.\n",
(unsigned long long)mddev->array_sectors);
- printk(KERN_INFO "raid0 : conf->spacing is %llu sectors.\n",
- (unsigned long long)conf->spacing);
- {
- sector_t s = raid0_size(mddev, 0, 0);
- sector_t space = conf->spacing;
- int round;
- conf->sector_shift = 0;
- if (sizeof(sector_t) > sizeof(u32)) {
- /*shift down space and s so that sector_div will work */
- while (space > (sector_t) (~(u32)0)) {
- s >>= 1;
- space >>= 1;
- s += 1; /* force round-up */
- conf->sector_shift++;
- }
- }
- round = sector_div(s, (u32)space) ? 1 : 0;
- nb_zone = s + round;
- }
- printk(KERN_INFO "raid0 : nb_zone is %d.\n", nb_zone);
- sectors = conf->strip_zone[cur].sectors;
-
- for (i=1; i< nb_zone; i++) {
- while (sectors <= conf->spacing) {
- cur++;
- sectors += conf->strip_zone[cur].sectors;
- }
- sectors -= conf->spacing;
- }
- if (conf->sector_shift) {
- conf->spacing >>= conf->sector_shift;
- /* round spacing up so when we divide by it, we
- * err on the side of too-low, which is safest
- */
- conf->spacing++;
- }
-
/* calculate the max read-ahead size.
* For read-ahead of large files to be effective, we need to
* readahead at least twice a whole stripe. i.e. number of devices
diff --git a/drivers/md/raid0.h b/drivers/md/raid0.h
index aac3613..218d7f3 100644
--- a/drivers/md/raid0.h
+++ b/drivers/md/raid0.h
@@ -15,9 +15,6 @@ struct raid0_private_data
struct strip_zone *strip_zone;
mdk_rdev_t **devlist; /* lists of rdevs, pointed to by strip_zone->dev */
int nr_strip_zones;
-
- sector_t spacing;
- int sector_shift; /* shift this before divide by spacing */
};

typedef struct raid0_private_data raid0_conf_t;
--
1.5.4.3