diff options
| -rw-r--r-- | drivers/md/raid5.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 52914d5cec7..b86ceba04f6 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2611,6 +2611,28 @@ static int raid5_congested(void *data, int bits) return 0; } +/* We want read requests to align with chunks where possible, + * but write requests don't need to. + */ +static int raid5_mergeable_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *biovec) +{ + mddev_t *mddev = q->queuedata; + sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); + int max; + unsigned int chunk_sectors = mddev->chunk_size >> 9; + unsigned int bio_sectors = bio->bi_size >> 9; + + if (bio_data_dir(bio)) + return biovec->bv_len; /* always allow writes to be mergeable */ + + max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; + if (max < 0) max = 0; + if (max <= biovec->bv_len && bio_sectors == 0) + return biovec->bv_len; + else + return max; +} + static int make_request(request_queue_t *q, struct bio * bi) { mddev_t *mddev = q->queuedata; @@ -3320,6 +3342,8 @@ static int run(mddev_t *mddev) mddev->array_size = mddev->size * (conf->previous_raid_disks - conf->max_degraded); + blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec); + return 0; abort: if (conf) { |