aoeblk.c

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/* Copyright (c) 2012 Coraid, Inc.  See COPYING for GPL terms. */
/*
 * aoeblk.c
 * block device routines
 */

#include <linux/kernel.h>
#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/genhd.h>
#include <linux/netdevice.h>
#include <linux/mutex.h>
#include <linux/export.h>
#include "aoe.h"

static DEFINE_MUTEX(aoeblk_mutex);
static struct kmem_cache *buf_pool_cache;

static ssize_t aoedisk_show_state(struct device *dev,
                  struct device_attribute *attr, char *page)
{
    struct gendisk *disk = dev_to_disk(dev);
    struct aoedev *d = disk->private_data;

    return snprintf(page, PAGE_SIZE,
            "%s%s\n",
            (d->flags & DEVFL_UP) ? "up" : "down",
            (d->flags & DEVFL_KICKME) ? ",kickme" :
            (d->nopen && !(d->flags & DEVFL_UP)) ? ",closewait" : "");
    /* I'd rather see nopen exported so we can ditch closewait */
}
static ssize_t aoedisk_show_mac(struct device *dev,
                struct device_attribute *attr, char *page)
{
    struct gendisk *disk = dev_to_disk(dev);
    struct aoedev *d = disk->private_data;
    struct aoetgt *t = d->targets[0];

    if (t == NULL)
        return snprintf(page, PAGE_SIZE, "none\n");
    return snprintf(page, PAGE_SIZE, "%pm\n", t->addr);
}
static ssize_t aoedisk_show_netif(struct device *dev,
                  struct device_attribute *attr, char *page)
{
    struct gendisk *disk = dev_to_disk(dev);
    struct aoedev *d = disk->private_data;
    struct net_device *nds[8], **nd, **nnd, **ne;
    struct aoetgt **t, **te;
    struct aoeif *ifp, *e;
    char *p;

    memset(nds, 0, sizeof nds);
    nd = nds;
    ne = nd + ARRAY_SIZE(nds);
    t = d->targets;
    te = t + NTARGETS;
    for (; t < te && *t; t++) {
        ifp = (*t)->ifs;
        e = ifp + NAOEIFS;
        for (; ifp < e && ifp->nd; ifp++) {
            for (nnd = nds; nnd < nd; nnd++)
                if (*nnd == ifp->nd)
                    break;
            if (nnd == nd && nd != ne)
                *nd++ = ifp->nd;
        }
    }

    ne = nd;
    nd = nds;
    if (*nd == NULL)
        return snprintf(page, PAGE_SIZE, "none\n");
    for (p = page; nd < ne; nd++)
        p += snprintf(p, PAGE_SIZE - (p-page), "%s%s",
            p == page ? "" : ",", (*nd)->name);
    p += snprintf(p, PAGE_SIZE - (p-page), "\n");
    return p-page;
}
/* firmware version */
static ssize_t aoedisk_show_fwver(struct device *dev,
                  struct device_attribute *attr, char *page)
{
    struct gendisk *disk = dev_to_disk(dev);
    struct aoedev *d = disk->private_data;

    return snprintf(page, PAGE_SIZE, "0x%04x\n", (unsigned int) d->fw_ver);
}

static DEVICE_ATTR(state, S_IRUGO, aoedisk_show_state, NULL);
static DEVICE_ATTR(mac, S_IRUGO, aoedisk_show_mac, NULL);
static DEVICE_ATTR(netif, S_IRUGO, aoedisk_show_netif, NULL);
static struct device_attribute dev_attr_firmware_version = {
    .attr = { .name = "firmware-version", .mode = S_IRUGO },
    .show = aoedisk_show_fwver,
};

static struct attribute *aoe_attrs[] = {
    &dev_attr_state.attr,
    &dev_attr_mac.attr,
    &dev_attr_netif.attr,
    &dev_attr_firmware_version.attr,
    NULL,
};

static const struct attribute_group attr_group = {
    .attrs = aoe_attrs,
};

static int
aoedisk_add_sysfs(struct aoedev *d)
{
    return sysfs_create_group(&disk_to_dev(d->gd)->kobj, &attr_group);
}
void
aoedisk_rm_sysfs(struct aoedev *d)
{
    sysfs_remove_group(&disk_to_dev(d->gd)->kobj, &attr_group);
}

static int
aoeblk_open(struct block_device *bdev, fmode_t mode)
{
    struct aoedev *d = bdev->bd_disk->private_data;
    ulong flags;

    mutex_lock(&aoeblk_mutex);
    spin_lock_irqsave(&d->lock, flags);
    if (d->flags & DEVFL_UP) {
        d->nopen++;
        spin_unlock_irqrestore(&d->lock, flags);
        mutex_unlock(&aoeblk_mutex);
        return 0;
    }
    spin_unlock_irqrestore(&d->lock, flags);
    mutex_unlock(&aoeblk_mutex);
    return -ENODEV;
}

static int
aoeblk_release(struct gendisk *disk, fmode_t mode)
{
    struct aoedev *d = disk->private_data;
    ulong flags;

    spin_lock_irqsave(&d->lock, flags);

    if (--d->nopen == 0) {
        spin_unlock_irqrestore(&d->lock, flags);
        aoecmd_cfg(d->aoemajor, d->aoeminor);
        return 0;
    }
    spin_unlock_irqrestore(&d->lock, flags);

    return 0;
}

static void
aoeblk_request(struct request_queue *q)
{
    struct aoedev *d;
    struct request *rq;

    d = q->queuedata;
    if ((d->flags & DEVFL_UP) == 0) {
        pr_info_ratelimited("aoe: device %ld.%d is not up\n",
            d->aoemajor, d->aoeminor);
        while ((rq = blk_peek_request(q))) {
            blk_start_request(rq);
            aoe_end_request(d, rq, 1);
        }
        return;
    }
    aoecmd_work(d);
}

static int
aoeblk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
    struct aoedev *d = bdev->bd_disk->private_data;

    if ((d->flags & DEVFL_UP) == 0) {
        printk(KERN_ERR "aoe: disk not up\n");
        return -ENODEV;
    }

    geo->cylinders = d->geo.cylinders;
    geo->heads = d->geo.heads;
    geo->sectors = d->geo.sectors;
    return 0;
}

static const struct block_device_operations aoe_bdops = {
    .open = aoeblk_open,
    .release = aoeblk_release,
    .getgeo = aoeblk_getgeo,
    .owner = THIS_MODULE,
};

/* alloc_disk and add_disk can sleep */
void
aoeblk_gdalloc(void *vp)
{
    struct aoedev *d = vp;
    struct gendisk *gd;
    mempool_t *mp;
    struct request_queue *q;
    enum { KB = 1024, MB = KB * KB, READ_AHEAD = 2 * MB, };
    ulong flags;

    gd = alloc_disk(AOE_PARTITIONS);
    if (gd == NULL) {
        pr_err("aoe: cannot allocate disk structure for %ld.%d\n",
            d->aoemajor, d->aoeminor);
        goto err;
    }

    mp = mempool_create(MIN_BUFS, mempool_alloc_slab, mempool_free_slab,
        buf_pool_cache);
    if (mp == NULL) {
        printk(KERN_ERR "aoe: cannot allocate bufpool for %ld.%d\n",
            d->aoemajor, d->aoeminor);
        goto err_disk;
    }
    q = blk_init_queue(aoeblk_request, &d->lock);
    if (q == NULL) {
        pr_err("aoe: cannot allocate block queue for %ld.%d\n",
            d->aoemajor, d->aoeminor);
        mempool_destroy(mp);
        goto err_disk;
    }

    d->blkq = blk_alloc_queue(GFP_KERNEL);
    if (!d->blkq)
        goto err_mempool;
    d->blkq->backing_dev_info.name = "aoe";
    if (bdi_init(&d->blkq->backing_dev_info))
        goto err_blkq;
    spin_lock_irqsave(&d->lock, flags);
    blk_queue_max_hw_sectors(d->blkq, BLK_DEF_MAX_SECTORS);
    q->backing_dev_info.ra_pages = READ_AHEAD / PAGE_CACHE_SIZE;
    d->bufpool = mp;
    d->blkq = gd->queue = q;
    q->queuedata = d;
    d->gd = gd;
    gd->major = AOE_MAJOR;
    gd->first_minor = d->sysminor;
    gd->fops = &aoe_bdops;
    gd->private_data = d;
    set_capacity(gd, d->ssize);
    snprintf(gd->disk_name, sizeof gd->disk_name, "etherd/e%ld.%d",
        d->aoemajor, d->aoeminor);

    d->flags &= ~DEVFL_GDALLOC;
    d->flags |= DEVFL_UP;

    spin_unlock_irqrestore(&d->lock, flags);

    add_disk(gd);
    aoedisk_add_sysfs(d);
    return;

err_blkq:
    blk_cleanup_queue(d->blkq);
    d->blkq = NULL;
err_mempool:
    mempool_destroy(d->bufpool);
err_disk:
    put_disk(gd);
err:
    spin_lock_irqsave(&d->lock, flags);
    d->flags &= ~DEVFL_GDALLOC;
    spin_unlock_irqrestore(&d->lock, flags);
}

void
aoeblk_exit(void)
{
    kmem_cache_destroy(buf_pool_cache);
}

int __init
aoeblk_init(void)
{
    buf_pool_cache = kmem_cache_create("aoe_bufs",
                       sizeof(struct buf),
                       0, 0, NULL);
    if (buf_pool_cache == NULL)
        return -ENOMEM;

    return 0;
}