X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fmd%2Flinear.c;fp=kernel%2Fdrivers%2Fmd%2Flinear.c;h=fa7d577f3d1257a6a029ae897702d74853d54919;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git diff --git a/kernel/drivers/md/linear.c b/kernel/drivers/md/linear.c new file mode 100644 index 000000000..fa7d577f3 --- /dev/null +++ b/kernel/drivers/md/linear.c @@ -0,0 +1,360 @@ +/* + linear.c : Multiple Devices driver for Linux + Copyright (C) 1994-96 Marc ZYNGIER + or + + + Linear mode management functions. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + You should have received a copy of the GNU General Public License + (for example /usr/src/linux/COPYING); if not, write to the Free + Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include +#include +#include +#include +#include +#include "md.h" +#include "linear.h" + +/* + * find which device holds a particular offset + */ +static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector) +{ + int lo, mid, hi; + struct linear_conf *conf; + + lo = 0; + hi = mddev->raid_disks - 1; + conf = mddev->private; + + /* + * Binary Search + */ + + while (hi > lo) { + + mid = (hi + lo) / 2; + if (sector < conf->disks[mid].end_sector) + hi = mid; + else + lo = mid + 1; + } + + return conf->disks + lo; +} + +/** + * linear_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. + * + * Return amount of bytes we can take at this offset + */ +static int linear_mergeable_bvec(struct mddev *mddev, + struct bvec_merge_data *bvm, + struct bio_vec *biovec) +{ + struct dev_info *dev0; + unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9; + sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); + int maxbytes = biovec->bv_len; + struct request_queue *subq; + + dev0 = which_dev(mddev, sector); + maxsectors = dev0->end_sector - sector; + subq = bdev_get_queue(dev0->rdev->bdev); + if (subq->merge_bvec_fn) { + bvm->bi_bdev = dev0->rdev->bdev; + bvm->bi_sector -= dev0->end_sector - dev0->rdev->sectors; + maxbytes = min(maxbytes, subq->merge_bvec_fn(subq, bvm, + biovec)); + } + + if (maxsectors < bio_sectors) + maxsectors = 0; + else + maxsectors -= bio_sectors; + + if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0) + return maxbytes; + + if (maxsectors > (maxbytes >> 9)) + return maxbytes; + else + return maxsectors << 9; +} + +static int linear_congested(struct mddev *mddev, int bits) +{ + struct linear_conf *conf; + int i, ret = 0; + + conf = mddev->private; + + for (i = 0; i < mddev->raid_disks && !ret ; i++) { + struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev); + ret |= bdi_congested(&q->backing_dev_info, bits); + } + + return ret; +} + +static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks) +{ + struct linear_conf *conf; + sector_t array_sectors; + + conf = mddev->private; + WARN_ONCE(sectors || raid_disks, + "%s does not support generic reshape\n", __func__); + array_sectors = conf->array_sectors; + + return array_sectors; +} + +static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks) +{ + struct linear_conf *conf; + struct md_rdev *rdev; + int i, cnt; + bool discard_supported = false; + + conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info), + GFP_KERNEL); + if (!conf) + return NULL; + + cnt = 0; + conf->array_sectors = 0; + + rdev_for_each(rdev, mddev) { + int j = rdev->raid_disk; + struct dev_info *disk = conf->disks + j; + sector_t sectors; + + if (j < 0 || j >= raid_disks || disk->rdev) { + printk(KERN_ERR "md/linear:%s: disk numbering problem. Aborting!\n", + mdname(mddev)); + goto out; + } + + disk->rdev = rdev; + if (mddev->chunk_sectors) { + sectors = rdev->sectors; + sector_div(sectors, mddev->chunk_sectors); + rdev->sectors = sectors * mddev->chunk_sectors; + } + + disk_stack_limits(mddev->gendisk, rdev->bdev, + rdev->data_offset << 9); + + conf->array_sectors += rdev->sectors; + cnt++; + + if (blk_queue_discard(bdev_get_queue(rdev->bdev))) + discard_supported = true; + } + if (cnt != raid_disks) { + printk(KERN_ERR "md/linear:%s: not enough drives present. Aborting!\n", + mdname(mddev)); + goto out; + } + + if (!discard_supported) + queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); + else + queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); + + /* + * Here we calculate the device offsets. + */ + conf->disks[0].end_sector = conf->disks[0].rdev->sectors; + + for (i = 1; i < raid_disks; i++) + conf->disks[i].end_sector = + conf->disks[i-1].end_sector + + conf->disks[i].rdev->sectors; + + return conf; + +out: + kfree(conf); + return NULL; +} + +static int linear_run (struct mddev *mddev) +{ + struct linear_conf *conf; + int ret; + + if (md_check_no_bitmap(mddev)) + return -EINVAL; + conf = linear_conf(mddev, mddev->raid_disks); + + if (!conf) + return 1; + mddev->private = conf; + md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); + + ret = md_integrity_register(mddev); + if (ret) { + kfree(conf); + mddev->private = NULL; + } + return ret; +} + +static int linear_add(struct mddev *mddev, struct md_rdev *rdev) +{ + /* Adding a drive to a linear array allows the array to grow. + * It is permitted if the new drive has a matching superblock + * already on it, with raid_disk equal to raid_disks. + * It is achieved by creating a new linear_private_data structure + * and swapping it in in-place of the current one. + * The current one is never freed until the array is stopped. + * This avoids races. + */ + struct linear_conf *newconf, *oldconf; + + if (rdev->saved_raid_disk != mddev->raid_disks) + return -EINVAL; + + rdev->raid_disk = rdev->saved_raid_disk; + rdev->saved_raid_disk = -1; + + newconf = linear_conf(mddev,mddev->raid_disks+1); + + if (!newconf) + return -ENOMEM; + + mddev_suspend(mddev); + oldconf = mddev->private; + mddev->raid_disks++; + mddev->private = newconf; + md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); + set_capacity(mddev->gendisk, mddev->array_sectors); + mddev_resume(mddev); + revalidate_disk(mddev->gendisk); + kfree(oldconf); + return 0; +} + +static void linear_free(struct mddev *mddev, void *priv) +{ + struct linear_conf *conf = priv; + + kfree(conf); +} + +static void linear_make_request(struct mddev *mddev, struct bio *bio) +{ + char b[BDEVNAME_SIZE]; + struct dev_info *tmp_dev; + struct bio *split; + sector_t start_sector, end_sector, data_offset; + + if (unlikely(bio->bi_rw & REQ_FLUSH)) { + md_flush_request(mddev, bio); + return; + } + + do { + tmp_dev = which_dev(mddev, bio->bi_iter.bi_sector); + start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors; + end_sector = tmp_dev->end_sector; + data_offset = tmp_dev->rdev->data_offset; + bio->bi_bdev = tmp_dev->rdev->bdev; + + if (unlikely(bio->bi_iter.bi_sector >= end_sector || + bio->bi_iter.bi_sector < start_sector)) + goto out_of_bounds; + + if (unlikely(bio_end_sector(bio) > end_sector)) { + /* This bio crosses a device boundary, so we have to + * split it. + */ + split = bio_split(bio, end_sector - + bio->bi_iter.bi_sector, + GFP_NOIO, fs_bio_set); + bio_chain(split, bio); + } else { + split = bio; + } + + split->bi_iter.bi_sector = split->bi_iter.bi_sector - + start_sector + data_offset; + + if (unlikely((split->bi_rw & REQ_DISCARD) && + !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) { + /* Just ignore it */ + bio_endio(split, 0); + } else + generic_make_request(split); + } while (split != bio); + return; + +out_of_bounds: + printk(KERN_ERR + "md/linear:%s: make_request: Sector %llu out of bounds on " + "dev %s: %llu sectors, offset %llu\n", + mdname(mddev), + (unsigned long long)bio->bi_iter.bi_sector, + bdevname(tmp_dev->rdev->bdev, b), + (unsigned long long)tmp_dev->rdev->sectors, + (unsigned long long)start_sector); + bio_io_error(bio); +} + +static void linear_status (struct seq_file *seq, struct mddev *mddev) +{ + + seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2); +} + +static void linear_quiesce(struct mddev *mddev, int state) +{ +} + +static struct md_personality linear_personality = +{ + .name = "linear", + .level = LEVEL_LINEAR, + .owner = THIS_MODULE, + .make_request = linear_make_request, + .run = linear_run, + .free = linear_free, + .status = linear_status, + .hot_add_disk = linear_add, + .size = linear_size, + .quiesce = linear_quiesce, + .congested = linear_congested, + .mergeable_bvec = linear_mergeable_bvec, +}; + +static int __init linear_init (void) +{ + return register_md_personality (&linear_personality); +} + +static void linear_exit (void) +{ + unregister_md_personality (&linear_personality); +} + +module_init(linear_init); +module_exit(linear_exit); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Linear device concatenation personality for MD"); +MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ +MODULE_ALIAS("md-linear"); +MODULE_ALIAS("md-level--1");