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ipath_fs.c

/*
 * 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/version.h>
#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 "ipath_kernel.h"

#define IPATHFS_MAGIC 0x726a77

static struct super_block *ipath_super;

static int ipathfs_mknod(struct inode *dir, struct dentry *dentry,
                   int 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_mode = mode;
      inode->i_uid = 0;
      inode->i_gid = 0;
      inode->i_blocks = 0;
      inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
      inode->i_private = data;
      if ((mode & S_IFMT) == S_IFDIR) {
            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, mode_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,
};

#define NUM_COUNTERS sizeof(struct infinipath_counters) / sizeof(u64)

static ssize_t atomic_counters_read(struct file *file, char __user *buf,
                            size_t count, loff_t *ppos)
{
      u64 counters[NUM_COUNTERS];
      u16 i;
      struct ipath_devdata *dd;

      dd = file->f_path.dentry->d_inode->i_private;

      for (i = 0; i < NUM_COUNTERS; i++)
            counters[i] = ipath_snap_cntr(dd, i);

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

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

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,
};

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,
                    (struct file_operations *) &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(&dcache_lock);
      spin_lock(&tmp->d_lock);
      if (!(d_unhashed(tmp) && tmp->d_inode)) {
            dget_locked(tmp);
            __d_drop(tmp);
            spin_unlock(&tmp->d_lock);
            spin_unlock(&dcache_lock);
            simple_unlink(parent->d_inode, tmp);
      } else {
            spin_unlock(&tmp->d_lock);
            spin_unlock(&dcache_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) {
                  deactivate_super(sb);
                  goto bail;
            }
            spin_lock_irqsave(&ipath_devs_lock, flags);
      }

      spin_unlock_irqrestore(&ipath_devs_lock, flags);

bail:
      return ret;
}

static int ipathfs_get_sb(struct file_system_type *fs_type, int flags,
                  const char *dev_name, void *data, struct vfsmount *mnt)
{
      int ret = get_sb_single(fs_type, flags, data,
                            ipathfs_fill_super, mnt);
      if (ret >= 0)
            ipath_super = mnt->mnt_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",
      .get_sb =   ipathfs_get_sb,
      .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);
}

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