From: Maneesh Soni o This patch implements the sysfs_dir_operations file_operations strucutre for sysfs directories. It uses the sysfs_dirent based tree for ->readdir() and ->lseek() methods instead of simple_dir_operations which use dentry based tree. o This also has the code for sysfs_get() and sysfs_put() which manipulates the reference counting for for sysfs_dirents. Signed-off-by: Andrew Morton --- 25-akpm/fs/sysfs/dir.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++- 25-akpm/fs/sysfs/mount.c | 2 25-akpm/fs/sysfs/sysfs.h | 27 +++++++ 3 files changed, 200 insertions(+), 2 deletions(-) diff -puN fs/sysfs/dir.c~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc fs/sysfs/dir.c --- 25/fs/sysfs/dir.c~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc Thu Jul 29 13:59:51 2004 +++ 25-akpm/fs/sysfs/dir.c Thu Jul 29 13:59:51 2004 @@ -15,7 +15,7 @@ DECLARE_RWSEM(sysfs_rename_sem); static int init_dir(struct inode * inode) { inode->i_op = &simple_dir_inode_operations; - inode->i_fop = &simple_dir_operations; + inode->i_fop = &sysfs_dir_operations; /* directory inodes start off with i_nlink == 2 (for "." entry) */ inode->i_nlink++; @@ -210,6 +210,177 @@ int sysfs_rename_dir(struct kobject * ko return error; } +/* get the name for corresponding element represented by the given sysfs_dirent + */ +const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) +{ + struct attribute * attr; + struct bin_attribute * bin_attr; + struct sysfs_symlink * sl; + + if (!sd || !sd->s_element) + BUG(); + + switch (sd->s_type) { + case SYSFS_KOBJECT: + case SYSFS_KOBJ_ATTR_GROUP: + /* Always have a dentry so use that */ + return sd->s_dentry->d_name.name; + + case SYSFS_KOBJ_ATTR: + attr = sd->s_element; + return attr->name; + + case SYSFS_KOBJ_BIN_ATTR: + bin_attr = sd->s_element; + return bin_attr->attr.name; + + case SYSFS_KOBJ_LINK: + sl = sd->s_element; + return sl->link_name; + } + return NULL; +} + +static int sysfs_dir_open(struct inode *inode, struct file *file) +{ + struct dentry * dentry = file->f_dentry; + struct sysfs_dirent * parent_sd = dentry->d_fsdata; + + down(&dentry->d_inode->i_sem); + file->private_data = sysfs_new_dirent(parent_sd, NULL, 0); + up(&dentry->d_inode->i_sem); + + return file->private_data ? 0 : -ENOMEM; + +} + +static int sysfs_dir_close(struct inode *inode, struct file *file) +{ + struct dentry * dentry = file->f_dentry; + struct sysfs_dirent * cursor = file->private_data; + + down(&dentry->d_inode->i_sem); + list_del_init(&cursor->s_sibling); + up(&dentry->d_inode->i_sem); + sysfs_put(file->private_data); + + return 0; +} + +/* Relationship between s_mode and the DT_xxx types */ +static inline unsigned char dt_type(struct sysfs_dirent *sd) +{ + return (sd->s_mode >> 12) & 15; +} + +static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) +{ + struct dentry *dentry = filp->f_dentry; + struct sysfs_dirent * parent_sd = dentry->d_fsdata; + struct sysfs_dirent *cursor = filp->private_data; + struct list_head *p, *q = &cursor->s_sibling; + ino_t ino; + int i = filp->f_pos; + + switch (i) { + case 0: + ino = dentry->d_inode->i_ino; + if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) + break; + filp->f_pos++; + i++; + /* fallthrough */ + case 1: + ino = parent_ino(dentry); + if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) + break; + filp->f_pos++; + i++; + /* fallthrough */ + default: + if (filp->f_pos == 2) { + list_del(q); + list_add(q, &parent_sd->s_children); + } + for (p=q->next; p!= &parent_sd->s_children; p=p->next) { + struct sysfs_dirent *next; + const char * name; + int len; + + next = list_entry(p, struct sysfs_dirent, + s_sibling); + if (!next->s_element) + continue; + + name = sysfs_get_name(next); + len = strlen(name); + if (next->s_dentry) + ino = next->s_dentry->d_inode->i_ino; + else + ino = iunique(sysfs_sb, 2); + + if (filldir(dirent, name, len, filp->f_pos, ino, + dt_type(next)) < 0) + return 0; + + list_del(q); + list_add(q, p); + p = q; + filp->f_pos++; + } + } + return 0; +} + +static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) +{ + struct dentry * dentry = file->f_dentry; + + down(&dentry->d_inode->i_sem); + switch (origin) { + case 1: + offset += file->f_pos; + case 0: + if (offset >= 0) + break; + default: + up(&file->f_dentry->d_inode->i_sem); + return -EINVAL; + } + if (offset != file->f_pos) { + file->f_pos = offset; + if (file->f_pos >= 2) { + struct sysfs_dirent *sd = dentry->d_fsdata; + struct sysfs_dirent *cursor = file->private_data; + struct list_head *p; + loff_t n = file->f_pos - 2; + + list_del(&cursor->s_sibling); + p = sd->s_children.next; + while (n && p != &sd->s_children) { + struct sysfs_dirent *next; + next = list_entry(p, struct sysfs_dirent, + s_sibling); + if (next->s_element) + n--; + p = p->next; + } + list_add_tail(&cursor->s_sibling, p); + } + } + up(&dentry->d_inode->i_sem); + return offset; +} + +struct file_operations sysfs_dir_operations = { + .open = sysfs_dir_open, + .release = sysfs_dir_close, + .llseek = sysfs_dir_lseek, + .read = generic_read_dir, + .readdir = sysfs_readdir, +}; + EXPORT_SYMBOL(sysfs_create_dir); EXPORT_SYMBOL(sysfs_remove_dir); EXPORT_SYMBOL(sysfs_rename_dir); diff -puN fs/sysfs/mount.c~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc fs/sysfs/mount.c --- 25/fs/sysfs/mount.c~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc Thu Jul 29 13:59:51 2004 +++ 25-akpm/fs/sysfs/mount.c Thu Jul 29 13:59:51 2004 @@ -43,7 +43,7 @@ static int sysfs_fill_super(struct super inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); if (inode) { inode->i_op = &simple_dir_inode_operations; - inode->i_fop = &simple_dir_operations; + inode->i_fop = &sysfs_dir_operations; /* directory inodes start off with i_nlink == 2 (for "." entry) */ inode->i_nlink++; } else { diff -puN fs/sysfs/sysfs.h~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc fs/sysfs/sysfs.h --- 25/fs/sysfs/sysfs.h~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc Thu Jul 29 13:59:51 2004 +++ 25-akpm/fs/sysfs/sysfs.h Thu Jul 29 13:59:51 2004 @@ -4,6 +4,8 @@ extern struct vfsmount * sysfs_mount; extern struct inode * sysfs_new_inode(mode_t mode); extern int sysfs_create(struct dentry *, int mode, int (*init)(struct inode *)); + +extern const unsigned char * sysfs_get_name(struct sysfs_dirent *sd); extern struct dentry * sysfs_get_dentry(struct dentry *, const char *); extern void sysfs_drop_dentry(struct sysfs_dirent *, struct dentry *); @@ -16,6 +18,8 @@ extern void sysfs_remove_subdir(struct d extern int sysfs_readlink(struct dentry *, char __user *, int ); extern int sysfs_follow_link(struct dentry *, struct nameidata *); extern struct rw_semaphore sysfs_rename_sem; +extern struct super_block * sysfs_sb; +extern struct file_operations sysfs_dir_operations; struct sysfs_symlink { char * link_name; @@ -58,3 +62,26 @@ struct sysfs_dirent * sysfs_new_dirent(s return sd; } + +static inline struct sysfs_dirent * sysfs_get(struct sysfs_dirent * sd) +{ + if (sd) { + WARN_ON(!atomic_read(&sd->s_count)); + atomic_inc(&sd->s_count); + } + return sd; +} + +static inline void sysfs_put(struct sysfs_dirent * sd) +{ + if (atomic_dec_and_test(&sd->s_count)) { + if (sd->s_type & SYSFS_KOBJ_LINK) { + struct sysfs_symlink * sl = sd->s_element; + kfree(sl->link_name); + kobject_put(sl->target_kobj); + kfree(sl); + } + kfree(sd); + } +} + _