Commit ccacc7d2 authored by Andre Noll's avatar Andre Noll Committed by NeilBrown

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: default avatarAndre Noll <maan@systemlinux.org>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 83838ed8
...@@ -213,16 +213,16 @@ static int create_strip_zones (mddev_t *mddev) ...@@ -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 * strip though as it's size has no bearing on the efficacy of the hash
* table. * table.
*/ */
conf->hash_spacing = curr_zone_start / 2; conf->spacing = curr_zone_start;
min_spacing = curr_zone_start / 2; min_spacing = curr_zone_start;
sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*)); sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*));
for (i=0; i < conf->nr_strip_zones-1; i++) { for (i=0; i < conf->nr_strip_zones-1; i++) {
sector_t sz = 0; sector_t s = 0;
for (j=i; j<conf->nr_strip_zones-1 && for (j = i; j < conf->nr_strip_zones - 1 &&
sz < min_spacing ; j++) s < min_spacing; j++)
sz += conf->strip_zone[j].sectors / 2; s += conf->strip_zone[j].sectors;
if (sz >= min_spacing && sz < conf->hash_spacing) if (s >= min_spacing && s < conf->spacing)
conf->hash_spacing = sz; conf->spacing = s;
} }
mddev->queue->unplug_fn = raid0_unplug; mddev->queue->unplug_fn = raid0_unplug;
...@@ -265,7 +265,7 @@ static int raid0_mergeable_bvec(struct request_queue *q, ...@@ -265,7 +265,7 @@ static int raid0_mergeable_bvec(struct request_queue *q,
static int raid0_run (mddev_t *mddev) static int raid0_run (mddev_t *mddev)
{ {
unsigned cur=0, i=0, nb_zone; unsigned cur=0, i=0, nb_zone;
s64 size; s64 sectors;
raid0_conf_t *conf; raid0_conf_t *conf;
mdk_rdev_t *rdev; mdk_rdev_t *rdev;
struct list_head *tmp; struct list_head *tmp;
...@@ -297,51 +297,51 @@ static int raid0_run (mddev_t *mddev) ...@@ -297,51 +297,51 @@ static int raid0_run (mddev_t *mddev)
rdev_for_each(rdev, tmp, mddev) rdev_for_each(rdev, tmp, mddev)
mddev->array_sectors += rdev->size * 2; mddev->array_sectors += rdev->size * 2;
printk("raid0 : md_size is %llu blocks.\n", printk(KERN_INFO "raid0 : md_size is %llu sectors.\n",
(unsigned long long)mddev->array_sectors / 2); (unsigned long long)mddev->array_sectors);
printk("raid0 : conf->hash_spacing is %llu blocks.\n", printk(KERN_INFO "raid0 : conf->spacing is %llu sectors.\n",
(unsigned long long)conf->hash_spacing); (unsigned long long)conf->spacing);
{ {
sector_t s = mddev->array_sectors / 2; sector_t s = mddev->array_sectors;
sector_t space = conf->hash_spacing; sector_t space = conf->spacing;
int round; int round;
conf->preshift = 0; conf->sector_shift = 0;
if (sizeof(sector_t) > sizeof(u32)) { if (sizeof(sector_t) > sizeof(u32)) {
/*shift down space and s so that sector_div will work */ /*shift down space and s so that sector_div will work */
while (space > (sector_t) (~(u32)0)) { while (space > (sector_t) (~(u32)0)) {
s >>= 1; s >>= 1;
space >>= 1; space >>= 1;
s += 1; /* force round-up */ s += 1; /* force round-up */
conf->preshift++; conf->sector_shift++;
} }
} }
round = sector_div(s, (u32)space) ? 1 : 0; round = sector_div(s, (u32)space) ? 1 : 0;
nb_zone = s + round; 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*)); nb_zone*sizeof(struct strip_zone*));
conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL); conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL);
if (!conf->hash_table) if (!conf->hash_table)
goto out_free_conf; 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; conf->hash_table[0] = conf->strip_zone + cur;
for (i=1; i< nb_zone; i++) { for (i=1; i< nb_zone; i++) {
while (size <= conf->hash_spacing) { while (sectors <= conf->spacing) {
cur++; 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; conf->hash_table[i] = conf->strip_zone + cur;
} }
if (conf->preshift) { if (conf->sector_shift) {
conf->hash_spacing >>= conf->preshift; conf->spacing >>= conf->sector_shift;
/* round hash_spacing up so when we divide by it, we /* round spacing up so when we divide by it, we
* err on the side of too-low, which is safest * err on the side of too-low, which is safest
*/ */
conf->hash_spacing++; conf->spacing++;
} }
/* calculate the max read-ahead size. /* calculate the max read-ahead size.
...@@ -435,8 +435,8 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio) ...@@ -435,8 +435,8 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio)
{ {
sector_t x = sector >> (conf->preshift + 1); sector_t x = sector >> conf->sector_shift;
sector_div(x, (u32)conf->hash_spacing); sector_div(x, (u32)conf->spacing);
zone = conf->hash_table[x]; zone = conf->hash_table[x];
} }
......
...@@ -19,8 +19,8 @@ struct raid0_private_data ...@@ -19,8 +19,8 @@ struct raid0_private_data
mdk_rdev_t **devlist; /* lists of rdevs, pointed to by strip_zone->dev */ mdk_rdev_t **devlist; /* lists of rdevs, pointed to by strip_zone->dev */
int nr_strip_zones; int nr_strip_zones;
sector_t hash_spacing; sector_t spacing;
int preshift; /* shift this before divide by hash_spacing */ int sector_shift; /* shift this before divide by spacing */
}; };
typedef struct raid0_private_data raid0_conf_t; typedef struct raid0_private_data raid0_conf_t;
......
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