From ccacc7d2cf03114a24ab903f710118e9e5d43273 Mon Sep 17 00:00:00 2001 From: Andre Noll Date: Fri, 9 Jan 2009 08:31:08 +1100 Subject: [PATCH] md: raid0: make hash_spacing and preshift sector-based. This patch renames the hash_spacing and preshift members of struct raid0_private_data to spacing and sector_shift respectively and changes the semantics as follows: We always have spacing = 2 * hash_spacing. In case sizeof(sector_t) > sizeof(u32) we also have sector_shift = preshift + 1 while sector_shift = preshift = 0 otherwise. Note that the values of nb_zone and zone are unaffected by these changes because in the sector_div() preceeding the assignement of these two variables both arguments double. Signed-off-by: Andre Noll Signed-off-by: NeilBrown --- drivers/md/raid0.c | 58 +++++++++++++++++++------------------- include/linux/raid/raid0.h | 4 +-- 2 files changed, 31 insertions(+), 31 deletions(-) diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index 6e85e88bbae9..90f5b24f6e6c 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -213,16 +213,16 @@ static int create_strip_zones (mddev_t *mddev) * strip though as it's size has no bearing on the efficacy of the hash * table. */ - conf->hash_spacing = curr_zone_start / 2; - min_spacing = curr_zone_start / 2; + 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 sz = 0; - for (j=i; jnr_strip_zones-1 && - sz < min_spacing ; j++) - sz += conf->strip_zone[j].sectors / 2; - if (sz >= min_spacing && sz < conf->hash_spacing) - conf->hash_spacing = sz; + 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; @@ -265,7 +265,7 @@ static int raid0_mergeable_bvec(struct request_queue *q, static int raid0_run (mddev_t *mddev) { unsigned cur=0, i=0, nb_zone; - s64 size; + s64 sectors; raid0_conf_t *conf; mdk_rdev_t *rdev; struct list_head *tmp; @@ -297,51 +297,51 @@ static int raid0_run (mddev_t *mddev) rdev_for_each(rdev, tmp, mddev) mddev->array_sectors += rdev->size * 2; - printk("raid0 : md_size is %llu blocks.\n", - (unsigned long long)mddev->array_sectors / 2); - printk("raid0 : conf->hash_spacing is %llu blocks.\n", - (unsigned long long)conf->hash_spacing); + 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 = mddev->array_sectors / 2; - sector_t space = conf->hash_spacing; + sector_t s = mddev->array_sectors; + sector_t space = conf->spacing; int round; - conf->preshift = 0; + 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->preshift++; + conf->sector_shift++; } } round = sector_div(s, (u32)space) ? 1 : 0; nb_zone = s + round; } - printk("raid0 : nb_zone is %d.\n", nb_zone); + printk(KERN_INFO "raid0 : nb_zone is %d.\n", nb_zone); - printk("raid0 : Allocating %Zd bytes for hash.\n", + printk(KERN_INFO "raid0 : Allocating %zu bytes for hash.\n", nb_zone*sizeof(struct strip_zone*)); conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL); if (!conf->hash_table) goto out_free_conf; - size = conf->strip_zone[cur].sectors / 2; + sectors = conf->strip_zone[cur].sectors; conf->hash_table[0] = conf->strip_zone + cur; for (i=1; i< nb_zone; i++) { - while (size <= conf->hash_spacing) { + while (sectors <= conf->spacing) { cur++; - size += conf->strip_zone[cur].sectors / 2; + sectors += conf->strip_zone[cur].sectors; } - size -= conf->hash_spacing; + sectors -= conf->spacing; conf->hash_table[i] = conf->strip_zone + cur; } - if (conf->preshift) { - conf->hash_spacing >>= conf->preshift; - /* round hash_spacing up so when we divide by it, we + 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->hash_spacing++; + conf->spacing++; } /* calculate the max read-ahead size. @@ -435,8 +435,8 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio) { - sector_t x = sector >> (conf->preshift + 1); - sector_div(x, (u32)conf->hash_spacing); + sector_t x = sector >> conf->sector_shift; + sector_div(x, (u32)conf->spacing); zone = conf->hash_table[x]; } diff --git a/include/linux/raid/raid0.h b/include/linux/raid/raid0.h index c12521d027e2..fd42aa87c391 100644 --- a/include/linux/raid/raid0.h +++ b/include/linux/raid/raid0.h @@ -19,8 +19,8 @@ struct raid0_private_data mdk_rdev_t **devlist; /* lists of rdevs, pointed to by strip_zone->dev */ int nr_strip_zones; - sector_t hash_spacing; - int preshift; /* shift this before divide by hash_spacing */ + sector_t spacing; + int sector_shift; /* shift this before divide by spacing */ }; typedef struct raid0_private_data raid0_conf_t;