ipath_fs.c

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/*
 * Copyright (c) 2006, 2007 QLogic Corporation. All rights reserved.
 * Copyright (c) 2006 PathScale, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/namei.h>
#include <linux/slab.h>

#include "ipath_kernel.h"

#define IPATHFS_MAGIC 0x726a77

static struct super_block *ipath_super;

static int ipathfs_mknod(struct inode *dir, struct dentry *dentry,
             umode_t mode, const struct file_operations *fops,
             void *data)
{
    int error;
    struct inode *inode = new_inode(dir->i_sb);

    if (!inode) {
        error = -EPERM;
        goto bail;
    }

    inode->i_ino = get_next_ino();
    inode->i_mode = mode;
    inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
    inode->i_private = data;
    if (S_ISDIR(mode)) {
        inode->i_op = &simple_dir_inode_operations;
        inc_nlink(inode);
        inc_nlink(dir);
    }

    inode->i_fop = fops;

    d_instantiate(dentry, inode);
    error = 0;

bail:
    return error;
}

static int create_file(const char *name, umode_t mode,
               struct dentry *parent, struct dentry **dentry,
               const struct file_operations *fops, void *data)
{
    int error;

    *dentry = NULL;
    mutex_lock(&parent->d_inode->i_mutex);
    *dentry = lookup_one_len(name, parent, strlen(name));
    if (!IS_ERR(*dentry))
        error = ipathfs_mknod(parent->d_inode, *dentry,
                      mode, fops, data);
    else
        error = PTR_ERR(*dentry);
    mutex_unlock(&parent->d_inode->i_mutex);

    return error;
}

static ssize_t atomic_stats_read(struct file *file, char __user *buf,
                 size_t count, loff_t *ppos)
{
    return simple_read_from_buffer(buf, count, ppos, &ipath_stats,
                       sizeof ipath_stats);
}

static const struct file_operations atomic_stats_ops = {
    .read = atomic_stats_read,
    .llseek = default_llseek,
};

static ssize_t atomic_counters_read(struct file *file, char __user *buf,
                    size_t count, loff_t *ppos)
{
    struct infinipath_counters counters;
    struct ipath_devdata *dd;

    dd = file->f_path.dentry->d_inode->i_private;
    dd->ipath_f_read_counters(dd, &counters);

    return simple_read_from_buffer(buf, count, ppos, &counters,
                       sizeof counters);
}

static const struct file_operations atomic_counters_ops = {
    .read = atomic_counters_read,
    .llseek = default_llseek,
};

static ssize_t flash_read(struct file *file, char __user *buf,
              size_t count, loff_t *ppos)
{
    struct ipath_devdata *dd;
    ssize_t ret;
    loff_t pos;
    char *tmp;

    pos = *ppos;

    if ( pos < 0) {
        ret = -EINVAL;
        goto bail;
    }

    if (pos >= sizeof(struct ipath_flash)) {
        ret = 0;
        goto bail;
    }

    if (count > sizeof(struct ipath_flash) - pos)
        count = sizeof(struct ipath_flash) - pos;

    tmp = kmalloc(count, GFP_KERNEL);
    if (!tmp) {
        ret = -ENOMEM;
        goto bail;
    }

    dd = file->f_path.dentry->d_inode->i_private;
    if (ipath_eeprom_read(dd, pos, tmp, count)) {
        ipath_dev_err(dd, "failed to read from flash\n");
        ret = -ENXIO;
        goto bail_tmp;
    }

    if (copy_to_user(buf, tmp, count)) {
        ret = -EFAULT;
        goto bail_tmp;
    }

    *ppos = pos + count;
    ret = count;

bail_tmp:
    kfree(tmp);

bail:
    return ret;
}

static ssize_t flash_write(struct file *file, const char __user *buf,
               size_t count, loff_t *ppos)
{
    struct ipath_devdata *dd;
    ssize_t ret;
    loff_t pos;
    char *tmp;

    pos = *ppos;

    if (pos != 0) {
        ret = -EINVAL;
        goto bail;
    }

    if (count != sizeof(struct ipath_flash)) {
        ret = -EINVAL;
        goto bail;
    }

    tmp = kmalloc(count, GFP_KERNEL);
    if (!tmp) {
        ret = -ENOMEM;
        goto bail;
    }

    if (copy_from_user(tmp, buf, count)) {
        ret = -EFAULT;
        goto bail_tmp;
    }

    dd = file->f_path.dentry->d_inode->i_private;
    if (ipath_eeprom_write(dd, pos, tmp, count)) {
        ret = -ENXIO;
        ipath_dev_err(dd, "failed to write to flash\n");
        goto bail_tmp;
    }

    *ppos = pos + count;
    ret = count;

bail_tmp:
    kfree(tmp);

bail:
    return ret;
}

static const struct file_operations flash_ops = {
    .read = flash_read,
    .write = flash_write,
    .llseek = default_llseek,
};

static int create_device_files(struct super_block *sb,
                   struct ipath_devdata *dd)
{
    struct dentry *dir, *tmp;
    char unit[10];
    int ret;

    snprintf(unit, sizeof unit, "%02d", dd->ipath_unit);
    ret = create_file(unit, S_IFDIR|S_IRUGO|S_IXUGO, sb->s_root, &dir,
              &simple_dir_operations, dd);
    if (ret) {
        printk(KERN_ERR "create_file(%s) failed: %d\n", unit, ret);
        goto bail;
    }

    ret = create_file("atomic_counters", S_IFREG|S_IRUGO, dir, &tmp,
              &atomic_counters_ops, dd);
    if (ret) {
        printk(KERN_ERR "create_file(%s/atomic_counters) "
               "failed: %d\n", unit, ret);
        goto bail;
    }

    ret = create_file("flash", S_IFREG|S_IWUSR|S_IRUGO, dir, &tmp,
              &flash_ops, dd);
    if (ret) {
        printk(KERN_ERR "create_file(%s/flash) "
               "failed: %d\n", unit, ret);
        goto bail;
    }

bail:
    return ret;
}

static int remove_file(struct dentry *parent, char *name)
{
    struct dentry *tmp;
    int ret;

    tmp = lookup_one_len(name, parent, strlen(name));

    if (IS_ERR(tmp)) {
        ret = PTR_ERR(tmp);
        goto bail;
    }

    spin_lock(&tmp->d_lock);
    if (!(d_unhashed(tmp) && tmp->d_inode)) {
        dget_dlock(tmp);
        __d_drop(tmp);
        spin_unlock(&tmp->d_lock);
        simple_unlink(parent->d_inode, tmp);
    } else
        spin_unlock(&tmp->d_lock);

    ret = 0;
bail:
    /*
     * We don't expect clients to care about the return value, but
     * it's there if they need it.
     */
    return ret;
}

static int remove_device_files(struct super_block *sb,
                   struct ipath_devdata *dd)
{
    struct dentry *dir, *root;
    char unit[10];
    int ret;

    root = dget(sb->s_root);
    mutex_lock(&root->d_inode->i_mutex);
    snprintf(unit, sizeof unit, "%02d", dd->ipath_unit);
    dir = lookup_one_len(unit, root, strlen(unit));

    if (IS_ERR(dir)) {
        ret = PTR_ERR(dir);
        printk(KERN_ERR "Lookup of %s failed\n", unit);
        goto bail;
    }

    remove_file(dir, "flash");
    remove_file(dir, "atomic_counters");
    d_delete(dir);
    ret = simple_rmdir(root->d_inode, dir);

bail:
    mutex_unlock(&root->d_inode->i_mutex);
    dput(root);
    return ret;
}

static int ipathfs_fill_super(struct super_block *sb, void *data,
                  int silent)
{
    struct ipath_devdata *dd, *tmp;
    unsigned long flags;
    int ret;

    static struct tree_descr files[] = {
        [2] = {"atomic_stats", &atomic_stats_ops, S_IRUGO},
        {""},
    };

    ret = simple_fill_super(sb, IPATHFS_MAGIC, files);
    if (ret) {
        printk(KERN_ERR "simple_fill_super failed: %d\n", ret);
        goto bail;
    }

    spin_lock_irqsave(&ipath_devs_lock, flags);

    list_for_each_entry_safe(dd, tmp, &ipath_dev_list, ipath_list) {
        spin_unlock_irqrestore(&ipath_devs_lock, flags);
        ret = create_device_files(sb, dd);
        if (ret)
            goto bail;
        spin_lock_irqsave(&ipath_devs_lock, flags);
    }

    spin_unlock_irqrestore(&ipath_devs_lock, flags);

bail:
    return ret;
}

static struct dentry *ipathfs_mount(struct file_system_type *fs_type,
            int flags, const char *dev_name, void *data)
{
    struct dentry *ret;
    ret = mount_single(fs_type, flags, data, ipathfs_fill_super);
    if (!IS_ERR(ret))
        ipath_super = ret->d_sb;
    return ret;
}

static void ipathfs_kill_super(struct super_block *s)
{
    kill_litter_super(s);
    ipath_super = NULL;
}

int ipathfs_add_device(struct ipath_devdata *dd)
{
    int ret;

    if (ipath_super == NULL) {
        ret = 0;
        goto bail;
    }

    ret = create_device_files(ipath_super, dd);

bail:
    return ret;
}

int ipathfs_remove_device(struct ipath_devdata *dd)
{
    int ret;

    if (ipath_super == NULL) {
        ret = 0;
        goto bail;
    }

    ret = remove_device_files(ipath_super, dd);

bail:
    return ret;
}

static struct file_system_type ipathfs_fs_type = {
    .owner =    THIS_MODULE,
    .name =     "ipathfs",
    .mount =    ipathfs_mount,
    .kill_sb =  ipathfs_kill_super,
};

int __init ipath_init_ipathfs(void)
{
    return register_filesystem(&ipathfs_fs_type);
}

void __exit ipath_exit_ipathfs(void)
{
    unregister_filesystem(&ipathfs_fs_type);
}