diff options
Diffstat (limited to 'drivers/md/raid0.c')
| -rw-r--r-- | drivers/md/raid0.c | 154 |
1 files changed, 85 insertions, 69 deletions
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index 7ef5cbf31bb..6f31f5596e0 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -188,16 +188,10 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) disk_stack_limits(mddev->gendisk, rdev1->bdev, rdev1->data_offset << 9); - /* as we don't honour merge_bvec_fn, we must never risk - * violating it, so limit ->max_segments to 1, lying within - * a single page. - */ - if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) { - blk_queue_max_segments(mddev->queue, 1); - blk_queue_segment_boundary(mddev->queue, - PAGE_CACHE_SIZE - 1); - } + if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) + conf->has_merge_bvec = 1; + if (!smallest || (rdev1->sectors < smallest->sectors)) smallest = rdev1; cnt++; @@ -290,8 +284,64 @@ abort: return err; } +/* Find the zone which holds a particular offset + * Update *sectorp to be an offset in that zone + */ +static struct strip_zone *find_zone(struct r0conf *conf, + 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 (i) + *sectorp = sector - z[i-1].zone_end; + return z + i; + } + BUG(); +} + +/* + * remaps the bio to the target device. we separate two flows. + * power 2 flow and a general flow for the sake of perfromance +*/ +static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, + sector_t sector, sector_t *sector_offset) +{ + unsigned int sect_in_chunk; + sector_t chunk; + struct r0conf *conf = mddev->private; + int raid_disks = conf->strip_zone[0].nb_dev; + unsigned int chunk_sects = mddev->chunk_sectors; + + if (is_power_of_2(chunk_sects)) { + int chunksect_bits = ffz(~chunk_sects); + /* find the sector offset inside the chunk */ + sect_in_chunk = sector & (chunk_sects - 1); + sector >>= chunksect_bits; + /* chunk in zone */ + chunk = *sector_offset; + /* quotient is the chunk in real device*/ + sector_div(chunk, zone->nb_dev << chunksect_bits); + } else{ + sect_in_chunk = sector_div(sector, chunk_sects); + chunk = *sector_offset; + sector_div(chunk, chunk_sects * zone->nb_dev); + } + /* + * position the bio over the real device + * real sector = chunk in device + starting of zone + * + the position in the chunk + */ + *sector_offset = (chunk * chunk_sects) + sect_in_chunk; + return conf->devlist[(zone - conf->strip_zone)*raid_disks + + sector_div(sector, zone->nb_dev)]; +} + /** - * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged + * raid0_mergeable_bvec -- tell bio layer if two requests can be merged * @q: request queue * @bvm: properties of new bio * @biovec: the request that could be merged to it. @@ -303,10 +353,15 @@ static int raid0_mergeable_bvec(struct request_queue *q, struct bio_vec *biovec) { struct mddev *mddev = q->queuedata; + struct r0conf *conf = mddev->private; sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); + sector_t sector_offset = sector; int max; unsigned int chunk_sectors = mddev->chunk_sectors; unsigned int bio_sectors = bvm->bi_size >> 9; + struct strip_zone *zone; + struct md_rdev *rdev; + struct request_queue *subq; if (is_power_of_2(chunk_sectors)) max = (chunk_sectors - ((sector & (chunk_sectors-1)) @@ -314,10 +369,27 @@ static int raid0_mergeable_bvec(struct request_queue *q, else max = (chunk_sectors - (sector_div(sector, chunk_sectors) + bio_sectors)) << 9; - if (max < 0) max = 0; /* bio_add cannot handle a negative return */ + if (max < 0) + max = 0; /* bio_add cannot handle a negative return */ if (max <= biovec->bv_len && bio_sectors == 0) return biovec->bv_len; - else + if (max < biovec->bv_len) + /* too small already, no need to check further */ + return max; + if (!conf->has_merge_bvec) + return max; + + /* May need to check subordinate device */ + sector = sector_offset; + zone = find_zone(mddev->private, §or_offset); + rdev = map_sector(mddev, zone, sector, §or_offset); + subq = bdev_get_queue(rdev->bdev); + if (subq->merge_bvec_fn) { + bvm->bi_bdev = rdev->bdev; + bvm->bi_sector = sector_offset + zone->dev_start + + rdev->data_offset; + return min(max, subq->merge_bvec_fn(subq, bvm, biovec)); + } else return max; } @@ -397,62 +469,6 @@ static int raid0_stop(struct mddev *mddev) return 0; } -/* Find the zone which holds a particular offset - * Update *sectorp to be an offset in that zone - */ -static struct strip_zone *find_zone(struct r0conf *conf, - 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 (i) - *sectorp = sector - z[i-1].zone_end; - return z + i; - } - BUG(); -} - -/* - * remaps the bio to the target device. we separate two flows. - * power 2 flow and a general flow for the sake of perfromance -*/ -static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, - sector_t sector, sector_t *sector_offset) -{ - unsigned int sect_in_chunk; - sector_t chunk; - struct r0conf *conf = mddev->private; - int raid_disks = conf->strip_zone[0].nb_dev; - unsigned int chunk_sects = mddev->chunk_sectors; - - if (is_power_of_2(chunk_sects)) { - int chunksect_bits = ffz(~chunk_sects); - /* find the sector offset inside the chunk */ - sect_in_chunk = sector & (chunk_sects - 1); - sector >>= chunksect_bits; - /* chunk in zone */ - chunk = *sector_offset; - /* quotient is the chunk in real device*/ - sector_div(chunk, zone->nb_dev << chunksect_bits); - } else{ - sect_in_chunk = sector_div(sector, chunk_sects); - chunk = *sector_offset; - sector_div(chunk, chunk_sects * zone->nb_dev); - } - /* - * position the bio over the real device - * real sector = chunk in device + starting of zone - * + the position in the chunk - */ - *sector_offset = (chunk * chunk_sects) + sect_in_chunk; - return conf->devlist[(zone - conf->strip_zone)*raid_disks - + sector_div(sector, zone->nb_dev)]; -} - /* * Is io distribute over 1 or more chunks ? */ @@ -505,7 +521,7 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio) } sector_offset = bio->bi_sector; - zone = find_zone(mddev->private, §or_offset); + zone = find_zone(mddev->private, §or_offset); tmp_dev = map_sector(mddev, zone, bio->bi_sector, §or_offset); bio->bi_bdev = tmp_dev->bdev; |