1 files changed, 539 insertions, 0 deletions

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
new file mode 100644
index 000000000000..e7d934eca06f
--- /dev/null
+++ b/drivers/md/raid0.c
@@ -0,0 +1,539 @@
+/*
+   raid0.c : Multiple Devices driver for Linux
+             Copyright (C) 1994-96 Marc ZYNGIER
+             <zyngier@ufr-info-p7.ibp.fr> or
+             <maz@gloups.fdn.fr>
+             Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
+
+
+   RAID-0 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 <linux/module.h>
+#include <linux/raid/raid0.h>
+
+#define MAJOR_NR MD_MAJOR
+#define MD_DRIVER
+#define MD_PERSONALITY
+
+static void raid0_unplug(request_queue_t *q)
+{
+        mddev_t *mddev = q->queuedata;
+        raid0_conf_t *conf = mddev_to_conf(mddev);
+        mdk_rdev_t **devlist = conf->strip_zone[0].dev;
+        int i;
+
+        for (i=0; i<mddev->raid_disks; i++) {
+                request_queue_t *r_queue = bdev_get_queue(devlist[i]->bdev);
+
+                if (r_queue->unplug_fn)
+                        r_queue->unplug_fn(r_queue);
+        }
+}
+
+static int raid0_issue_flush(request_queue_t *q, struct gendisk *disk,
+                             sector_t *error_sector)
+{
+        mddev_t *mddev = q->queuedata;
+        raid0_conf_t *conf = mddev_to_conf(mddev);
+        mdk_rdev_t **devlist = conf->strip_zone[0].dev;
+        int i, ret = 0;
+
+        for (i=0; i<mddev->raid_disks && ret == 0; i++) {
+                struct block_device *bdev = devlist[i]->bdev;
+                request_queue_t *r_queue = bdev_get_queue(bdev);
+
+                if (!r_queue->issue_flush_fn)
+                        ret = -EOPNOTSUPP;
+                else
+                        ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
+        }
+        return ret;
+}
+
+
+static int create_strip_zones (mddev_t *mddev)
+{
+        int i, c, j;
+        sector_t current_offset, curr_zone_offset;
+        sector_t min_spacing;
+        raid0_conf_t *conf = mddev_to_conf(mddev);
+        mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;
+        struct list_head *tmp1, *tmp2;
+        struct strip_zone *zone;
+        int cnt;
+        char b[BDEVNAME_SIZE];
+ 
+        /*
+         * The number of 'same size groups'
+         */
+        conf->nr_strip_zones = 0;
+ 
+        ITERATE_RDEV(mddev,rdev1,tmp1) {
+                printk("raid0: looking at %s\n",
+                        bdevname(rdev1->bdev,b));
+                c = 0;
+                ITERATE_RDEV(mddev,rdev2,tmp2) {
+                        printk("raid0:   comparing %s(%llu)",
+                               bdevname(rdev1->bdev,b),
+                               (unsigned long long)rdev1->size);
+                        printk(" with %s(%llu)\n",
+                               bdevname(rdev2->bdev,b),
+                               (unsigned long long)rdev2->size);
+                        if (rdev2 == rdev1) {
+                                printk("raid0:   END\n");
+                                break;
+                        }
+                        if (rdev2->size == rdev1->size)
+                        {
+                                /*
+                                 * Not unique, don't count it as a new
+                                 * group
+                                 */
+                                printk("raid0:   EQUAL\n");
+                                c = 1;
+                                break;
+                        }
+                        printk("raid0:   NOT EQUAL\n");
+                }
+                if (!c) {
+                        printk("raid0:   ==> UNIQUE\n");
+                        conf->nr_strip_zones++;
+                        printk("raid0: %d zones\n", conf->nr_strip_zones);
+                }
+        }
+        printk("raid0: FINAL %d zones\n", conf->nr_strip_zones);
+
+        conf->strip_zone = kmalloc(sizeof(struct strip_zone)*
+                                conf->nr_strip_zones, GFP_KERNEL);
+        if (!conf->strip_zone)
+                return 1;
+        conf->devlist = kmalloc(sizeof(mdk_rdev_t*)*
+                                conf->nr_strip_zones*mddev->raid_disks,
+                                GFP_KERNEL);
+        if (!conf->devlist)
+                return 1;
+
+        memset(conf->strip_zone, 0,sizeof(struct strip_zone)*
+                                   conf->nr_strip_zones);
+        memset(conf->devlist, 0,
+               sizeof(mdk_rdev_t*) * conf->nr_strip_zones * mddev->raid_disks);
+
+        /* The first zone must contain all devices, so here we check that
+         * there is a proper alignment of slots to devices and find them all
+         */
+        zone = &conf->strip_zone[0];
+        cnt = 0;
+        smallest = NULL;
+        zone->dev = conf->devlist;
+        ITERATE_RDEV(mddev, rdev1, tmp1) {
+                int j = rdev1->raid_disk;
+
+                if (j < 0 || j >= mddev->raid_disks) {
+                        printk("raid0: bad disk number %d - aborting!\n", j);
+                        goto abort;
+                }
+                if (zone->dev[j]) {
+                        printk("raid0: multiple devices for %d - aborting!\n",
+                                j);
+                        goto abort;
+                }
+                zone->dev[j] = rdev1;
+
+                blk_queue_stack_limits(mddev->queue,
+                                       rdev1->bdev->bd_disk->queue);
+                /* as we don't honour merge_bvec_fn, we must never risk
+                 * violating it, so limit ->max_sector to one PAGE, as
+                 * a one page request is never in violation.
+                 */
+
+                if (rdev1->bdev->bd_disk->queue->merge_bvec_fn &&
+                    mddev->queue->max_sectors > (PAGE_SIZE>>9))
+                        blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
+
+                if (!smallest || (rdev1->size <smallest->size))
+                        smallest = rdev1;
+                cnt++;
+        }
+        if (cnt != mddev->raid_disks) {
+                printk("raid0: too few disks (%d of %d) - aborting!\n",
+                        cnt, mddev->raid_disks);
+                goto abort;
+        }
+        zone->nb_dev = cnt;
+        zone->size = smallest->size * cnt;
+        zone->zone_offset = 0;
+
+        current_offset = smallest->size;
+        curr_zone_offset = zone->size;
+
+        /* now do the other zones */
+        for (i = 1; i < conf->nr_strip_zones; i++)
+        {
+                zone = conf->strip_zone + i;
+                zone->dev = conf->strip_zone[i-1].dev + mddev->raid_disks;
+
+                printk("raid0: zone %d\n", i);
+                zone->dev_offset = current_offset;
+                smallest = NULL;
+                c = 0;
+
+                for (j=0; j<cnt; j++) {
+                        char b[BDEVNAME_SIZE];
+                        rdev = conf->strip_zone[0].dev[j];
+                        printk("raid0: checking %s ...", bdevname(rdev->bdev,b));
+                        if (rdev->size > current_offset)
+                        {
+                                printk(" contained as device %d\n", c);
+                                zone->dev[c] = rdev;
+                                c++;
+                                if (!smallest || (rdev->size <smallest->size)) {
+                                        smallest = rdev;
+                                        printk("  (%llu) is smallest!.\n", 
+                                                (unsigned long long)rdev->size);
+                                }
+                        } else
+                                printk(" nope.\n");
+                }
+
+                zone->nb_dev = c;
+                zone->size = (smallest->size - current_offset) * c;
+                printk("raid0: zone->nb_dev: %d, size: %llu\n",
+                        zone->nb_dev, (unsigned long long)zone->size);
+
+                zone->zone_offset = curr_zone_offset;
+                curr_zone_offset += zone->size;
+
+                current_offset = smallest->size;
+                printk("raid0: current zone offset: %llu\n",
+                        (unsigned long long)current_offset);
+        }
+
+        /* Now find appropriate hash spacing.
+         * We want a number which causes most hash entries to cover
+         * at most two strips, but the hash table must be at most
+         * 1 PAGE.  We choose the smallest strip, or contiguous collection
+         * of strips, that has big enough size.  We never consider the last
+         * strip though as it's size has no bearing on the efficacy of the hash
+         * table.
+         */
+        conf->hash_spacing = curr_zone_offset;
+        min_spacing = curr_zone_offset;
+        sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*));
+        for (i=0; i < conf->nr_strip_zones-1; i++) {
+                sector_t sz = 0;
+                for (j=i; j<conf->nr_strip_zones-1 &&
+                             sz < min_spacing ; j++)
+                        sz += conf->strip_zone[j].size;
+                if (sz >= min_spacing && sz < conf->hash_spacing)
+                        conf->hash_spacing = sz;
+        }
+
+        mddev->queue->unplug_fn = raid0_unplug;
+
+        mddev->queue->issue_flush_fn = raid0_issue_flush;
+
+        printk("raid0: done.\n");
+        return 0;
+ abort:
+        return 1;
+}
+
+/**
+ *      raid0_mergeable_bvec -- tell bio layer if a 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.
+ *
+ *      Return amount of bytes we can accept at this offset
+ */
+static int raid0_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;
+
+        max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
+        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 
+                return max;
+}
+
+static int raid0_run (mddev_t *mddev)
+{
+        unsigned  cur=0, i=0, nb_zone;
+        s64 size;
+        raid0_conf_t *conf;
+        mdk_rdev_t *rdev;
+        struct list_head *tmp;
+
+        printk("%s: setting max_sectors to %d, segment boundary to %d\n",
+               mdname(mddev),
+               mddev->chunk_size >> 9,
+               (mddev->chunk_size>>1)-1);
+        blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
+        blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1);
+
+        conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL);
+        if (!conf)
+                goto out;
+        mddev->private = (void *)conf;
+ 
+        conf->strip_zone = NULL;
+        conf->devlist = NULL;
+        if (create_strip_zones (mddev)) 
+                goto out_free_conf;
+
+        /* calculate array device size */
+        mddev->array_size = 0;
+        ITERATE_RDEV(mddev,rdev,tmp)
+                mddev->array_size += rdev->size;
+
+        printk("raid0 : md_size is %llu blocks.\n", 
+                (unsigned long long)mddev->array_size);
+        printk("raid0 : conf->hash_spacing is %llu blocks.\n",
+                (unsigned long long)conf->hash_spacing);
+        {
+#if __GNUC__ < 3
+                volatile
+#endif
+                sector_t s = mddev->array_size;
+                sector_t space = conf->hash_spacing;
+                int round;
+                conf->preshift = 0;
+                if (sizeof(sector_t) > sizeof(unsigned long)) {
+                        /*shift down space and s so that sector_div will work */
+                        while (space > (sector_t) (~(unsigned long)0)) {
+                                s >>= 1;
+                                space >>= 1;
+                                s += 1; /* force round-up */
+                                conf->preshift++;
+                        }
+                }
+                round = sector_div(s, (unsigned long)space) ? 1 : 0;
+                nb_zone = s + round;
+        }
+        printk("raid0 : nb_zone is %d.\n", nb_zone);
+
+        printk("raid0 : Allocating %Zd bytes for hash.\n",
+                                nb_zone*sizeof(struct strip_zone*));
+        conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL);
+        if (!conf->hash_table)
+                goto out_free_conf;
+        size = conf->strip_zone[cur].size;
+
+        for (i=0; i< nb_zone; i++) {
+                conf->hash_table[i] = conf->strip_zone + cur;
+                while (size <= conf->hash_spacing) {
+                        cur++;
+                        size += conf->strip_zone[cur].size;
+                }
+                size -= conf->hash_spacing;
+        }
+        if (conf->preshift) {
+                conf->hash_spacing >>= conf->preshift;
+                /* round hash_spacing up so when we divide by it, we
+                 * err on the side of too-low, which is safest
+                 */
+                conf->hash_spacing++;
+        }
+
+        /* calculate the max read-ahead size.
+         * For read-ahead of large files to be effective, we need to
+         * readahead at least twice a whole stripe. i.e. number of devices
+         * multiplied by chunk size times 2.
+         * If an individual device has an ra_pages greater than the
+         * chunk size, then we will not drive that device as hard as it
+         * wants.  We consider this a configuration error: a larger
+         * chunksize should be used in that case.
+         */
+        {
+                int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_CACHE_SIZE;
+                if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
+                        mddev->queue->backing_dev_info.ra_pages = 2* stripe;
+        }
+
+
+        blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
+        return 0;
+
+out_free_conf:
+        if (conf->strip_zone)
+                kfree(conf->strip_zone);
+        if (conf->devlist)
+                kfree (conf->devlist);
+        kfree(conf);
+        mddev->private = NULL;
+out:
+        return 1;
+}
+
+static int raid0_stop (mddev_t *mddev)
+{
+        raid0_conf_t *conf = mddev_to_conf(mddev);
+
+        blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
+        kfree (conf->hash_table);
+        conf->hash_table = NULL;
+        kfree (conf->strip_zone);
+        conf->strip_zone = NULL;
+        kfree (conf);
+        mddev->private = NULL;
+
+        return 0;
+}
+
+static int raid0_make_request (request_queue_t *q, struct bio *bio)
+{
+        mddev_t *mddev = q->queuedata;
+        unsigned int sect_in_chunk, chunksize_bits,  chunk_size, chunk_sects;
+        raid0_conf_t *conf = mddev_to_conf(mddev);
+        struct strip_zone *zone;
+        mdk_rdev_t *tmp_dev;
+        unsigned long chunk;
+        sector_t block, rsect;
+
+        if (bio_data_dir(bio)==WRITE) {
+                disk_stat_inc(mddev->gendisk, writes);
+                disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
+        } else {
+                disk_stat_inc(mddev->gendisk, reads);
+                disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
+        }
+
+        chunk_size = mddev->chunk_size >> 10;
+        chunk_sects = mddev->chunk_size >> 9;
+        chunksize_bits = ffz(~chunk_size);
+        block = bio->bi_sector >> 1;
+        
+
+        if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) {
+                struct bio_pair *bp;
+                /* Sanity check -- queue functions should prevent this happening */
+                if (bio->bi_vcnt != 1 ||
+                    bio->bi_idx != 0)
+                        goto bad_map;
+                /* This is a one page bio that upper layers
+                 * refuse to split for us, so we need to split it.
+                 */
+                bp = bio_split(bio, bio_split_pool, chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
+                if (raid0_make_request(q, &bp->bio1))
+                        generic_make_request(&bp->bio1);
+                if (raid0_make_request(q, &bp->bio2))
+                        generic_make_request(&bp->bio2);
+
+                bio_pair_release(bp);
+                return 0;
+        }
+ 
+
+        {
+#if __GNUC__ < 3
+                volatile
+#endif
+                sector_t x = block >> conf->preshift;
+                sector_div(x, (unsigned long)conf->hash_spacing);
+                zone = conf->hash_table[x];
+        }
+ 
+        while (block >= (zone->zone_offset + zone->size)) 
+                zone++;
+    
+        sect_in_chunk = bio->bi_sector & ((chunk_size<<1) -1);
+
+
+        {
+                sector_t x =  (block - zone->zone_offset) >> chunksize_bits;
+
+                sector_div(x, zone->nb_dev);
+                chunk = x;
+                BUG_ON(x != (sector_t)chunk);
+
+                x = block >> chunksize_bits;
+                tmp_dev = zone->dev[sector_div(x, zone->nb_dev)];
+        }
+        rsect = (((chunk << chunksize_bits) + zone->dev_offset)<<1)
+                + sect_in_chunk;
+ 
+        bio->bi_bdev = tmp_dev->bdev;
+        bio->bi_sector = rsect + tmp_dev->data_offset;
+
+        /*
+         * Let the main block layer submit the IO and resolve recursion:
+         */
+        return 1;
+
+bad_map:
+        printk("raid0_make_request bug: can't convert block across chunks"
+                " or bigger than %dk %llu %d\n", chunk_size, 
+                (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
+
+        bio_io_error(bio, bio->bi_size);
+        return 0;
+}
+                           
+static void raid0_status (struct seq_file *seq, mddev_t *mddev)
+{
+#undef MD_DEBUG
+#ifdef MD_DEBUG
+        int j, k, h;
+        char b[BDEVNAME_SIZE];
+        raid0_conf_t *conf = mddev_to_conf(mddev);
+  
+        h = 0;
+        for (j = 0; j < conf->nr_strip_zones; j++) {
+                seq_printf(seq, "      z%d", j);
+                if (conf->hash_table[h] == conf->strip_zone+j)
+                        seq_printf("(h%d)", h++);
+                seq_printf(seq, "=[");
+                for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
+                        seq_printf (seq, "%s/", bdevname(
+                                conf->strip_zone[j].dev[k]->bdev,b));
+
+                seq_printf (seq, "] zo=%d do=%d s=%d\n",
+                                conf->strip_zone[j].zone_offset,
+                                conf->strip_zone[j].dev_offset,
+                                conf->strip_zone[j].size);
+        }
+#endif
+        seq_printf(seq, " %dk chunks", mddev->chunk_size/1024);
+        return;
+}
+
+static mdk_personality_t raid0_personality=
+{
+        .name           = "raid0",
+        .owner          = THIS_MODULE,
+        .make_request   = raid0_make_request,
+        .run            = raid0_run,
+        .stop           = raid0_stop,
+        .status         = raid0_status,
+};
+
+static int __init raid0_init (void)
+{
+        return register_md_personality (RAID0, &raid0_personality);
+}
+
+static void raid0_exit (void)
+{
+        unregister_md_personality (RAID0);
+}
+
+module_init(raid0_init);
+module_exit(raid0_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("md-personality-2"); /* RAID0 */