diff options
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/file.c | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index e2fafc0a9b36..7dfcc3317490 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -45,12 +45,23 @@ struct sysfs_open_dirent { struct sysfs_buffer { size_t count; char *page; - const struct sysfs_ops *ops; struct mutex mutex; int event; struct list_head list; }; +/* + * Determine ktype->sysfs_ops for the given sysfs_dirent. This function + * must be called while holding an active reference. + */ +static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd) +{ + struct kobject *kobj = sd->s_parent->s_dir.kobj; + + lockdep_assert_held(sd); + return kobj->ktype ? kobj->ktype->sysfs_ops : NULL; +} + /** * fill_read_buffer - allocate and fill buffer from object. * @dentry: dentry pointer. @@ -66,7 +77,7 @@ static int fill_read_buffer(struct dentry *dentry, struct sysfs_buffer *buffer) { struct sysfs_dirent *attr_sd = dentry->d_fsdata; struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; - const struct sysfs_ops *ops = buffer->ops; + const struct sysfs_ops *ops; int ret = 0; ssize_t count; @@ -80,6 +91,8 @@ static int fill_read_buffer(struct dentry *dentry, struct sysfs_buffer *buffer) return -ENODEV; buffer->event = atomic_read(&attr_sd->s_attr.open->event); + + ops = sysfs_file_ops(attr_sd); count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page); sysfs_put_active(attr_sd); @@ -191,13 +204,14 @@ static int flush_write_buffer(struct dentry *dentry, { struct sysfs_dirent *attr_sd = dentry->d_fsdata; struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; - const struct sysfs_ops *ops = buffer->ops; + const struct sysfs_ops *ops; int rc; /* need attr_sd for attr and ops, its parent for kobj */ if (!sysfs_get_active(attr_sd)) return -ENODEV; + ops = sysfs_file_ops(attr_sd); rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count); sysfs_put_active(attr_sd); @@ -205,7 +219,6 @@ static int flush_write_buffer(struct dentry *dentry, return rc; } - /** * sysfs_write_file - write an attribute. * @file: file pointer @@ -334,14 +347,11 @@ static int sysfs_open_file(struct inode *inode, struct file *file) return -ENODEV; /* every kobject with an attribute needs a ktype assigned */ - if (kobj->ktype && kobj->ktype->sysfs_ops) - ops = kobj->ktype->sysfs_ops; - else { - WARN(1, KERN_ERR - "missing sysfs attribute operations for kobject: %s\n", - kobject_name(kobj)); + ops = sysfs_file_ops(attr_sd); + if (WARN(!ops, KERN_ERR + "missing sysfs attribute operations for kobject: %s\n", + kobject_name(kobj))) goto err_out; - } /* File needs write support. * The inode's perms must say it's ok, @@ -370,7 +380,6 @@ static int sysfs_open_file(struct inode *inode, struct file *file) goto err_out; mutex_init(&buffer->mutex); - buffer->ops = ops; file->private_data = buffer; /* make sure we have open dirent struct */ |