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![Cheng Renquan](/assets/img/avatar_default.png)
The rdev_for_each macro defined in <linux/raid/md_k.h> is identical to list_for_each_entry_safe, from <linux/list.h>, it should be defined to use list_for_each_entry_safe, instead of reinventing the wheel. But some calls to each_entry_safe don't really need a safe version, just a direct list_for_each_entry is enough, this could save a temp variable (tmp) in every function that used rdev_for_each. In this patch, most rdev_for_each loops are replaced by list_for_each_entry, totally save many tmp vars; and only in the other situations that will call list_del to delete an entry, the safe version is used. Signed-off-by: Cheng Renquan <crquan@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de>
529 lines
14 KiB
C
529 lines
14 KiB
C
/*
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raid0.c : Multiple Devices driver for Linux
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Copyright (C) 1994-96 Marc ZYNGIER
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<zyngier@ufr-info-p7.ibp.fr> or
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<maz@gloups.fdn.fr>
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Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
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RAID-0 management functions.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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You should have received a copy of the GNU General Public License
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(for example /usr/src/linux/COPYING); if not, write to the Free
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Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/raid/raid0.h>
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static void raid0_unplug(struct request_queue *q)
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{
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mddev_t *mddev = q->queuedata;
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raid0_conf_t *conf = mddev_to_conf(mddev);
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mdk_rdev_t **devlist = conf->strip_zone[0].dev;
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int i;
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for (i=0; i<mddev->raid_disks; i++) {
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struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev);
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blk_unplug(r_queue);
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}
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}
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static int raid0_congested(void *data, int bits)
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{
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mddev_t *mddev = data;
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raid0_conf_t *conf = mddev_to_conf(mddev);
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mdk_rdev_t **devlist = conf->strip_zone[0].dev;
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int i, ret = 0;
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for (i = 0; i < mddev->raid_disks && !ret ; i++) {
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struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
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ret |= bdi_congested(&q->backing_dev_info, bits);
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}
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return ret;
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}
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static int create_strip_zones (mddev_t *mddev)
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{
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int i, c, j;
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sector_t current_start, curr_zone_start;
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sector_t min_spacing;
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raid0_conf_t *conf = mddev_to_conf(mddev);
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mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;
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struct strip_zone *zone;
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int cnt;
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char b[BDEVNAME_SIZE];
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/*
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* The number of 'same size groups'
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*/
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conf->nr_strip_zones = 0;
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list_for_each_entry(rdev1, &mddev->disks, same_set) {
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printk(KERN_INFO "raid0: looking at %s\n",
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bdevname(rdev1->bdev,b));
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c = 0;
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list_for_each_entry(rdev2, &mddev->disks, same_set) {
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printk(KERN_INFO "raid0: comparing %s(%llu)",
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bdevname(rdev1->bdev,b),
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(unsigned long long)rdev1->size);
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printk(KERN_INFO " with %s(%llu)\n",
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bdevname(rdev2->bdev,b),
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(unsigned long long)rdev2->size);
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if (rdev2 == rdev1) {
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printk(KERN_INFO "raid0: END\n");
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break;
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}
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if (rdev2->size == rdev1->size)
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{
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/*
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* Not unique, don't count it as a new
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* group
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*/
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printk(KERN_INFO "raid0: EQUAL\n");
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c = 1;
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break;
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}
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printk(KERN_INFO "raid0: NOT EQUAL\n");
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}
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if (!c) {
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printk(KERN_INFO "raid0: ==> UNIQUE\n");
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conf->nr_strip_zones++;
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printk(KERN_INFO "raid0: %d zones\n",
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conf->nr_strip_zones);
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}
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}
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printk(KERN_INFO "raid0: FINAL %d zones\n", conf->nr_strip_zones);
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conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
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conf->nr_strip_zones, GFP_KERNEL);
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if (!conf->strip_zone)
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return 1;
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conf->devlist = kzalloc(sizeof(mdk_rdev_t*)*
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conf->nr_strip_zones*mddev->raid_disks,
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GFP_KERNEL);
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if (!conf->devlist)
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return 1;
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/* The first zone must contain all devices, so here we check that
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* there is a proper alignment of slots to devices and find them all
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*/
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zone = &conf->strip_zone[0];
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cnt = 0;
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smallest = NULL;
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zone->dev = conf->devlist;
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list_for_each_entry(rdev1, &mddev->disks, same_set) {
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int j = rdev1->raid_disk;
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if (j < 0 || j >= mddev->raid_disks) {
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printk(KERN_ERR "raid0: bad disk number %d - "
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"aborting!\n", j);
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goto abort;
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}
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if (zone->dev[j]) {
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printk(KERN_ERR "raid0: multiple devices for %d - "
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"aborting!\n", j);
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goto abort;
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}
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zone->dev[j] = rdev1;
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blk_queue_stack_limits(mddev->queue,
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rdev1->bdev->bd_disk->queue);
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/* as we don't honour merge_bvec_fn, we must never risk
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* violating it, so limit ->max_sector to one PAGE, as
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* a one page request is never in violation.
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*/
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if (rdev1->bdev->bd_disk->queue->merge_bvec_fn &&
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mddev->queue->max_sectors > (PAGE_SIZE>>9))
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blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
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if (!smallest || (rdev1->size <smallest->size))
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smallest = rdev1;
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cnt++;
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}
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if (cnt != mddev->raid_disks) {
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printk(KERN_ERR "raid0: too few disks (%d of %d) - "
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"aborting!\n", cnt, mddev->raid_disks);
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goto abort;
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}
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zone->nb_dev = cnt;
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zone->sectors = smallest->size * cnt * 2;
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zone->zone_start = 0;
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current_start = smallest->size * 2;
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curr_zone_start = zone->sectors;
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/* now do the other zones */
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for (i = 1; i < conf->nr_strip_zones; i++)
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{
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zone = conf->strip_zone + i;
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zone->dev = conf->strip_zone[i-1].dev + mddev->raid_disks;
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printk(KERN_INFO "raid0: zone %d\n", i);
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zone->dev_start = current_start;
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smallest = NULL;
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c = 0;
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for (j=0; j<cnt; j++) {
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char b[BDEVNAME_SIZE];
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rdev = conf->strip_zone[0].dev[j];
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printk(KERN_INFO "raid0: checking %s ...",
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bdevname(rdev->bdev, b));
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if (rdev->size > current_start / 2) {
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printk(KERN_INFO " contained as device %d\n",
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c);
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zone->dev[c] = rdev;
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c++;
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if (!smallest || (rdev->size <smallest->size)) {
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smallest = rdev;
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printk(KERN_INFO " (%llu) is smallest!.\n",
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(unsigned long long)rdev->size);
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}
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} else
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printk(KERN_INFO " nope.\n");
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}
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zone->nb_dev = c;
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zone->sectors = (smallest->size * 2 - current_start) * c;
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printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n",
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zone->nb_dev, (unsigned long long)zone->sectors);
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zone->zone_start = curr_zone_start;
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curr_zone_start += zone->sectors;
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current_start = smallest->size * 2;
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printk(KERN_INFO "raid0: current zone start: %llu\n",
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(unsigned long long)current_start);
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}
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/* Now find appropriate hash spacing.
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* We want a number which causes most hash entries to cover
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* at most two strips, but the hash table must be at most
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* 1 PAGE. We choose the smallest strip, or contiguous collection
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* of strips, that has big enough size. We never consider the last
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* strip though as it's size has no bearing on the efficacy of the hash
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* table.
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*/
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conf->spacing = curr_zone_start;
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min_spacing = curr_zone_start;
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sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*));
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for (i=0; i < conf->nr_strip_zones-1; i++) {
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sector_t s = 0;
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for (j = i; j < conf->nr_strip_zones - 1 &&
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s < min_spacing; j++)
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s += conf->strip_zone[j].sectors;
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if (s >= min_spacing && s < conf->spacing)
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conf->spacing = s;
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}
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mddev->queue->unplug_fn = raid0_unplug;
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mddev->queue->backing_dev_info.congested_fn = raid0_congested;
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mddev->queue->backing_dev_info.congested_data = mddev;
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printk(KERN_INFO "raid0: done.\n");
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return 0;
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abort:
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return 1;
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}
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/**
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* raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
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* @q: request queue
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* @bvm: properties of new bio
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* @biovec: the request that could be merged to it.
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*
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* Return amount of bytes we can accept at this offset
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*/
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static int raid0_mergeable_bvec(struct request_queue *q,
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struct bvec_merge_data *bvm,
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struct bio_vec *biovec)
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{
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mddev_t *mddev = q->queuedata;
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sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
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int max;
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unsigned int chunk_sectors = mddev->chunk_size >> 9;
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unsigned int bio_sectors = bvm->bi_size >> 9;
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max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
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if (max < 0) max = 0; /* bio_add cannot handle a negative return */
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if (max <= biovec->bv_len && bio_sectors == 0)
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return biovec->bv_len;
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else
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return max;
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}
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static int raid0_run (mddev_t *mddev)
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{
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unsigned cur=0, i=0, nb_zone;
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s64 sectors;
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raid0_conf_t *conf;
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mdk_rdev_t *rdev;
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if (mddev->chunk_size == 0) {
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printk(KERN_ERR "md/raid0: non-zero chunk size required.\n");
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return -EINVAL;
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}
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printk(KERN_INFO "%s: setting max_sectors to %d, segment boundary to %d\n",
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mdname(mddev),
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mddev->chunk_size >> 9,
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(mddev->chunk_size>>1)-1);
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blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
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blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1);
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mddev->queue->queue_lock = &mddev->queue->__queue_lock;
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conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL);
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if (!conf)
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goto out;
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mddev->private = (void *)conf;
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conf->strip_zone = NULL;
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conf->devlist = NULL;
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if (create_strip_zones (mddev))
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goto out_free_conf;
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/* calculate array device size */
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mddev->array_sectors = 0;
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list_for_each_entry(rdev, &mddev->disks, same_set)
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mddev->array_sectors += rdev->size * 2;
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printk(KERN_INFO "raid0 : md_size is %llu sectors.\n",
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(unsigned long long)mddev->array_sectors);
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printk(KERN_INFO "raid0 : conf->spacing is %llu sectors.\n",
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(unsigned long long)conf->spacing);
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{
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sector_t s = mddev->array_sectors;
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sector_t space = conf->spacing;
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int round;
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conf->sector_shift = 0;
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if (sizeof(sector_t) > sizeof(u32)) {
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/*shift down space and s so that sector_div will work */
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while (space > (sector_t) (~(u32)0)) {
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s >>= 1;
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space >>= 1;
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s += 1; /* force round-up */
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conf->sector_shift++;
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}
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}
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round = sector_div(s, (u32)space) ? 1 : 0;
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nb_zone = s + round;
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}
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printk(KERN_INFO "raid0 : nb_zone is %d.\n", nb_zone);
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printk(KERN_INFO "raid0 : Allocating %zu bytes for hash.\n",
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nb_zone*sizeof(struct strip_zone*));
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conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL);
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if (!conf->hash_table)
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goto out_free_conf;
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sectors = conf->strip_zone[cur].sectors;
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conf->hash_table[0] = conf->strip_zone + cur;
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for (i=1; i< nb_zone; i++) {
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while (sectors <= conf->spacing) {
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cur++;
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sectors += conf->strip_zone[cur].sectors;
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}
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sectors -= conf->spacing;
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conf->hash_table[i] = conf->strip_zone + cur;
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}
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if (conf->sector_shift) {
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conf->spacing >>= conf->sector_shift;
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/* round spacing up so when we divide by it, we
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* err on the side of too-low, which is safest
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*/
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conf->spacing++;
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}
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/* calculate the max read-ahead size.
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* For read-ahead of large files to be effective, we need to
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* readahead at least twice a whole stripe. i.e. number of devices
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* multiplied by chunk size times 2.
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* If an individual device has an ra_pages greater than the
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* chunk size, then we will not drive that device as hard as it
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* wants. We consider this a configuration error: a larger
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* chunksize should be used in that case.
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*/
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{
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int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_SIZE;
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if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
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mddev->queue->backing_dev_info.ra_pages = 2* stripe;
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}
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blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
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return 0;
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out_free_conf:
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kfree(conf->strip_zone);
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kfree(conf->devlist);
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kfree(conf);
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mddev->private = NULL;
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out:
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return -ENOMEM;
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}
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static int raid0_stop (mddev_t *mddev)
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{
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raid0_conf_t *conf = mddev_to_conf(mddev);
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blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
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kfree(conf->hash_table);
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conf->hash_table = NULL;
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kfree(conf->strip_zone);
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conf->strip_zone = NULL;
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kfree(conf);
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mddev->private = NULL;
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return 0;
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}
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static int raid0_make_request (struct request_queue *q, struct bio *bio)
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{
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mddev_t *mddev = q->queuedata;
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unsigned int sect_in_chunk, chunksect_bits, chunk_sects;
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raid0_conf_t *conf = mddev_to_conf(mddev);
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struct strip_zone *zone;
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mdk_rdev_t *tmp_dev;
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sector_t chunk;
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sector_t sector, rsect;
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const int rw = bio_data_dir(bio);
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int cpu;
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if (unlikely(bio_barrier(bio))) {
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bio_endio(bio, -EOPNOTSUPP);
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return 0;
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}
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cpu = part_stat_lock();
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part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
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part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
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bio_sectors(bio));
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part_stat_unlock();
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chunk_sects = mddev->chunk_size >> 9;
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chunksect_bits = ffz(~chunk_sects);
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sector = bio->bi_sector;
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if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) {
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struct bio_pair *bp;
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/* Sanity check -- queue functions should prevent this happening */
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if (bio->bi_vcnt != 1 ||
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bio->bi_idx != 0)
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goto bad_map;
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/* This is a one page bio that upper layers
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* refuse to split for us, so we need to split it.
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*/
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bp = bio_split(bio, chunk_sects - (bio->bi_sector & (chunk_sects - 1)));
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if (raid0_make_request(q, &bp->bio1))
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generic_make_request(&bp->bio1);
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if (raid0_make_request(q, &bp->bio2))
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generic_make_request(&bp->bio2);
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bio_pair_release(bp);
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return 0;
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}
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{
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sector_t x = sector >> conf->sector_shift;
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sector_div(x, (u32)conf->spacing);
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zone = conf->hash_table[x];
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}
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while (sector >= zone->zone_start + zone->sectors)
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zone++;
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sect_in_chunk = bio->bi_sector & (chunk_sects - 1);
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{
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sector_t x = (sector - zone->zone_start) >> chunksect_bits;
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sector_div(x, zone->nb_dev);
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chunk = x;
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x = sector >> chunksect_bits;
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tmp_dev = zone->dev[sector_div(x, zone->nb_dev)];
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}
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rsect = (chunk << chunksect_bits) + zone->dev_start + sect_in_chunk;
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bio->bi_bdev = tmp_dev->bdev;
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bio->bi_sector = rsect + tmp_dev->data_offset;
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/*
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* Let the main block layer submit the IO and resolve recursion:
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*/
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return 1;
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bad_map:
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printk("raid0_make_request bug: can't convert block across chunks"
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" or bigger than %dk %llu %d\n", chunk_sects / 2,
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(unsigned long long)bio->bi_sector, bio->bi_size >> 10);
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bio_io_error(bio);
|
|
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(seq, "(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, "] zs=%d ds=%d s=%d\n",
|
|
conf->strip_zone[j].zone_start,
|
|
conf->strip_zone[j].dev_start,
|
|
conf->strip_zone[j].sectors);
|
|
}
|
|
#endif
|
|
seq_printf(seq, " %dk chunks", mddev->chunk_size/1024);
|
|
return;
|
|
}
|
|
|
|
static struct mdk_personality raid0_personality=
|
|
{
|
|
.name = "raid0",
|
|
.level = 0,
|
|
.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_personality);
|
|
}
|
|
|
|
static void raid0_exit (void)
|
|
{
|
|
unregister_md_personality (&raid0_personality);
|
|
}
|
|
|
|
module_init(raid0_init);
|
|
module_exit(raid0_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("md-personality-2"); /* RAID0 */
|
|
MODULE_ALIAS("md-raid0");
|
|
MODULE_ALIAS("md-level-0");
|