diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/linear.c | 95 |
1 files changed, 66 insertions, 29 deletions
diff --git a/drivers/md/linear.c b/drivers/md/linear.c index 4991ba54336..bb279fad2fd 100644 --- a/drivers/md/linear.c +++ b/drivers/md/linear.c @@ -38,7 +38,8 @@ static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector) /* * sector_div(a,b) returns the remainer and sets a to a/b */ - (void)sector_div(block, conf->smallest->size); + block >>= conf->preshift; + (void)sector_div(block, conf->hash_spacing); hash = conf->hash_table[block]; while ((sector>>1) >= (hash->size + hash->offset)) @@ -47,7 +48,7 @@ static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector) } /** - * linear_mergeable_bvec -- tell bio layer if a two requests can be merged + * linear_mergeable_bvec -- tell bio layer if two requests can be merged * @q: request queue * @bio: the buffer head that's been built up so far * @biovec: the request that could be merged to it. @@ -116,7 +117,7 @@ static int linear_run (mddev_t *mddev) dev_info_t **table; mdk_rdev_t *rdev; int i, nb_zone, cnt; - sector_t start; + sector_t min_spacing; sector_t curr_offset; struct list_head *tmp; @@ -127,11 +128,6 @@ static int linear_run (mddev_t *mddev) memset(conf, 0, sizeof(*conf) + mddev->raid_disks*sizeof(dev_info_t)); mddev->private = conf; - /* - * Find the smallest device. - */ - - conf->smallest = NULL; cnt = 0; mddev->array_size = 0; @@ -159,8 +155,6 @@ static int linear_run (mddev_t *mddev) disk->size = rdev->size; mddev->array_size += rdev->size; - if (!conf->smallest || (disk->size < conf->smallest->size)) - conf->smallest = disk; cnt++; } if (cnt != mddev->raid_disks) { @@ -168,6 +162,36 @@ static int linear_run (mddev_t *mddev) goto out; } + min_spacing = mddev->array_size; + sector_div(min_spacing, PAGE_SIZE/sizeof(struct dev_info *)); + + /* min_spacing is the minimum spacing that will fit the hash + * table in one PAGE. This may be much smaller than needed. + * We find the smallest non-terminal set of consecutive devices + * that is larger than min_spacing as use the size of that as + * the actual spacing + */ + conf->hash_spacing = mddev->array_size; + for (i=0; i < cnt-1 ; i++) { + sector_t sz = 0; + int j; + for (j=i; i<cnt-1 && sz < min_spacing ; j++) + sz += conf->disks[j].size; + if (sz >= min_spacing && sz < conf->hash_spacing) + conf->hash_spacing = sz; + } + + /* hash_spacing may be too large for sector_div to work with, + * so we might need to pre-shift + */ + conf->preshift = 0; + if (sizeof(sector_t) > sizeof(u32)) { + sector_t space = conf->hash_spacing; + while (space > (sector_t)(~(u32)0)) { + space >>= 1; + conf->preshift++; + } + } /* * This code was restructured to work around a gcc-2.95.3 internal * compiler error. Alter it with care. @@ -177,39 +201,52 @@ static int linear_run (mddev_t *mddev) unsigned round; unsigned long base; - sz = mddev->array_size; - base = conf->smallest->size; + sz = mddev->array_size >> conf->preshift; + sz += 1; /* force round-up */ + base = conf->hash_spacing >> conf->preshift; round = sector_div(sz, base); - nb_zone = conf->nr_zones = sz + (round ? 1 : 0); + nb_zone = sz + (round ? 1 : 0); } - - conf->hash_table = kmalloc (sizeof (dev_info_t*) * nb_zone, + BUG_ON(nb_zone > PAGE_SIZE / sizeof(struct dev_info *)); + + conf->hash_table = kmalloc (sizeof (struct dev_info *) * nb_zone, GFP_KERNEL); if (!conf->hash_table) goto out; /* * Here we generate the linear hash table + * First calculate the device offsets. */ + conf->disks[0].offset = 0; + for (i=1; i<mddev->raid_disks; i++) + conf->disks[i].offset = + conf->disks[i-1].offset + + conf->disks[i-1].size; + table = conf->hash_table; - start = 0; curr_offset = 0; - for (i = 0; i < cnt; i++) { - dev_info_t *disk = conf->disks + i; + i = 0; + for (curr_offset = 0; + curr_offset < mddev->array_size; + curr_offset += conf->hash_spacing) { - disk->offset = curr_offset; - curr_offset += disk->size; + while (i < mddev->raid_disks-1 && + curr_offset >= conf->disks[i+1].offset) + i++; - /* 'curr_offset' is the end of this disk - * 'start' is the start of table + *table ++ = conf->disks + i; + } + + if (conf->preshift) { + conf->hash_spacing >>= conf->preshift; + /* round hash_spacing up so that when we divide by it, + * we err on the side of "too-low", which is safest. */ - while (start < curr_offset) { - *table++ = disk; - start += conf->smallest->size; - } + conf->hash_spacing++; } - if (table-conf->hash_table != nb_zone) - BUG(); + + BUG_ON(table - conf->hash_table > nb_zone); blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec); mddev->queue->unplug_fn = linear_unplug; @@ -299,7 +336,7 @@ static void linear_status (struct seq_file *seq, mddev_t *mddev) sector_t s = 0; seq_printf(seq, " "); - for (j = 0; j < conf->nr_zones; j++) + for (j = 0; j < mddev->raid_disks; j++) { char b[BDEVNAME_SIZE]; s += conf->smallest_size; |