sysfs: add sysfs_open_file->sd and ->file

sysfs will be converted to use seq_file for read path, which will make
it difficult to pass around multiple pointers directly.  This patch
adds sysfs_open_file->sd and ->file so that we can reach all the
necessary data structures from sysfs_open_file.

flush_write_buffer() is updated to drop @dentry which was used to
discover the sysfs_dirent as it's now available through
sysfs_open_file->sd.

This patch doesn't cause any behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 4b55bcf..af6e909 100644 (file)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -45,6 +45,8 @@ struct sysfs_open_dirent {
 };
 
 struct sysfs_open_file {
+       struct sysfs_dirent     *sd;
+       struct file             *file;
        size_t                  count;
        char                    *page;
        struct mutex            mutex;
@@ -192,7 +194,6 @@ static int fill_write_buffer(struct sysfs_open_file *of,
 
 /**
  *     flush_write_buffer - push buffer to kobject.
- *     @dentry:        dentry to the attribute
  *     @of:            open file
  *     @count:         number of bytes
  *
@@ -200,22 +201,20 @@ static int fill_write_buffer(struct sysfs_open_file *of,
  *     dealing with, then call the store() method for the attribute,
  *     passing the buffer that we acquired in fill_write_buffer().
  */
-static int flush_write_buffer(struct dentry *dentry,
-                             struct sysfs_open_file *of, size_t count)
+static int flush_write_buffer(struct sysfs_open_file *of, size_t count)
 {
-       struct sysfs_dirent *attr_sd = dentry->d_fsdata;
-       struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
+       struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
        const struct sysfs_ops *ops;
        int rc;
 
-       /* need attr_sd for attr and ops, its parent for kobj */
-       if (!sysfs_get_active(attr_sd))
+       /* need @of->sd for attr and ops, its parent for kobj */
+       if (!sysfs_get_active(of->sd))
                return -ENODEV;
 
-       ops = sysfs_file_ops(attr_sd);
-       rc = ops->store(kobj, attr_sd->s_attr.attr, of->page, count);
+       ops = sysfs_file_ops(of->sd);
+       rc = ops->store(kobj, of->sd->s_attr.attr, of->page, count);
 
-       sysfs_put_active(attr_sd);
+       sysfs_put_active(of->sd);
 
        return rc;
 }
@@ -245,7 +244,7 @@ static ssize_t sysfs_write_file(struct file *file, const char __user *buf,
        mutex_lock(&of->mutex);
        len = fill_write_buffer(of, buf, count);
        if (len > 0)
-               len = flush_write_buffer(file->f_path.dentry, of, len);
+               len = flush_write_buffer(of, len);
        if (len > 0)
                *ppos += len;
        mutex_unlock(&of->mutex);
@@ -385,6 +384,8 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
                goto err_out;
 
        mutex_init(&of->mutex);
+       of->sd = attr_sd;
+       of->file = file;
        file->private_data = of;
 
        /* make sure we have open dirent struct */