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Commit eda52025 authored by Patrick Mochel's avatar Patrick Mochel
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sysfs: marry api with struct kobject. 

This works on obviating the need for a separate data type to describe a sysfs
directory (which was renamed from struct driver_dir_entry to struct sysfs_dir).

All sysfs creation and removal functions now take a struct kobject, instead
of a struct sysfs_dir. This kobject is embedded in ->d_fsdata of the directory.

sysfs_create_dir() takes only 1 parameter now: the object that we're creating
the directory for. The parent dentry is derived by looking at the object's 
parent. 

sysfs_create_file() takes the object as the first parameter, and the attribute
as the second, which makes more sense from an API perspective. 

sysfs_remove_file() now takes an attribute as a second parameter, to be 
consistent with the creation function.

sysfs_remove_link() is created, which is basically the old sysfs_remove_file().
(symlinks don't have an attribute associated with them; only a name, which was
prohibiting the previous change). 

open() and close() look for a kobject now, and do refcounting directly on the
object. Because of that, we don't need the ->open() and ->close() callbacks
in struct sysfs_ops, so they've been removed. 

read() and write() also now look for a kobject now. 

The comments have been updated, too.
parent c637d6b1
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Showing with 167 additions and 138 deletions
fs/sysfs/inode.c
View file @ eda52025
...@@ -33,7 +33,7 @@ ...@@ -33,7 +33,7 @@
#include <linux/module.h> #include <linux/module.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <linux/backing-dev.h> #include <linux/backing-dev.h>
#include <linux/sysfs.h> #include <linux/kobject.h>
#include <asm/uaccess.h> #include <asm/uaccess.h>
...@@ -154,30 +154,35 @@ static int sysfs_unlink(struct inode *dir, struct dentry *dentry) ...@@ -154,30 +154,35 @@ static int sysfs_unlink(struct inode *dir, struct dentry *dentry)
} }
/** /**
* sysfs_read_file - "read" data from a file. * sysfs_read_file - read an attribute.
* @file: file pointer * @file: file pointer.
* @buf: buffer to fill * @buf: buffer to fill.
* @count: number of bytes to read * @count: number of bytes to read.
* @ppos: starting offset in file * @ppos: starting offset in file.
*
* Userspace wants to read an attribute file. The attribute descriptor
* is in the file's ->d_fsdata. The target object is in the directory's
* ->d_fsdata.
* *
* Userspace wants data from a file. It is up to the creator of the file to * We allocate a %PAGE_SIZE buffer, and pass it to the object's ->show()
* provide that data. * method (along with the object). We loop doing this until @count is
* There is a struct device_attribute embedded in file->private_data. We * satisfied, or ->show() returns %0.
* obtain that and check if the read callback is implemented. If so, we call
* it, passing the data field of the file entry.
* Said callback is responsible for filling the buffer and returning the number
* of bytes it put in it. We update @ppos correctly.
*/ */
static ssize_t static ssize_t
sysfs_read_file(struct file *file, char *buf, size_t count, loff_t *ppos) sysfs_read_file(struct file *file, char *buf, size_t count, loff_t *ppos)
{ {
struct attribute * attr = file->f_dentry->d_fsdata; struct attribute * attr = file->f_dentry->d_fsdata;
struct driver_dir_entry * dir; struct sysfs_ops * ops = NULL;
struct kobject * kobj;
unsigned char *page; unsigned char *page;
ssize_t retval = 0; ssize_t retval = 0;
dir = file->f_dentry->d_parent->d_fsdata; kobj = file->f_dentry->d_parent->d_fsdata;
if (!dir->ops->show) if (kobj)
ops = kobj->dir.ops;
if (!ops || !ops->show)
return 0; return 0;
if (count > PAGE_SIZE) if (count > PAGE_SIZE)
...@@ -190,7 +195,7 @@ sysfs_read_file(struct file *file, char *buf, size_t count, loff_t *ppos) ...@@ -190,7 +195,7 @@ sysfs_read_file(struct file *file, char *buf, size_t count, loff_t *ppos)
while (count > 0) { while (count > 0) {
ssize_t len; ssize_t len;
len = dir->ops->show(dir,attr,page,count,*ppos); len = ops->show(kobj,attr,page,count,*ppos);
if (len <= 0) { if (len <= 0) {
if (len < 0) if (len < 0)
...@@ -214,27 +219,32 @@ sysfs_read_file(struct file *file, char *buf, size_t count, loff_t *ppos) ...@@ -214,27 +219,32 @@ sysfs_read_file(struct file *file, char *buf, size_t count, loff_t *ppos)
} }
/** /**
* sysfs_write_file - "write" to a file * sysfs_write_file - write an attribute.
* @file: file pointer * @file: file pointer
* @buf: data to write * @buf: data to write
* @count: number of bytes * @count: number of bytes
* @ppos: starting offset * @ppos: starting offset
* *
* Similarly to sysfs_read_file, we act essentially as a bit pipe. * Identical to sysfs_read_file(), though going the opposite direction.
* We check for a "write" callback in file->private_data, and pass * We allocate a %PAGE_SIZE buffer and copy in the userspace buffer. We
* @buffer, @count, @ppos, and the file entry's data to the callback. * pass that to the object's ->store() method until we reach @count or
* The number of bytes written is returned, and we handle updating * ->store() returns %0 or less.
* @ppos properly.
*/ */
static ssize_t static ssize_t
sysfs_write_file(struct file *file, const char *buf, size_t count, loff_t *ppos) sysfs_write_file(struct file *file, const char *buf, size_t count, loff_t *ppos)
{ {
struct attribute * attr = file->f_dentry->d_fsdata; struct attribute * attr = file->f_dentry->d_fsdata;
struct driver_dir_entry * dir; struct sysfs_ops * ops = NULL;
struct kobject * kobj;
ssize_t retval = 0; ssize_t retval = 0;
char * page; char * page;
dir = file->f_dentry->d_parent->d_fsdata; kobj = file->f_dentry->d_parent->d_fsdata;
if (kobj)
ops = kobj->dir.ops;
if (!ops || !ops->store)
return 0;
page = (char *)__get_free_page(GFP_KERNEL); page = (char *)__get_free_page(GFP_KERNEL);
if (!page) if (!page)
...@@ -249,7 +259,7 @@ sysfs_write_file(struct file *file, const char *buf, size_t count, loff_t *ppos) ...@@ -249,7 +259,7 @@ sysfs_write_file(struct file *file, const char *buf, size_t count, loff_t *ppos)
while (count > 0) { while (count > 0) {
ssize_t len; ssize_t len;
len = dir->ops->store(dir,attr,page + retval,count,*ppos); len = ops->store(kobj,attr,page + retval,count,*ppos);
if (len <= 0) { if (len <= 0) {
if (len < 0) if (len < 0)
...@@ -268,29 +278,24 @@ sysfs_write_file(struct file *file, const char *buf, size_t count, loff_t *ppos) ...@@ -268,29 +278,24 @@ sysfs_write_file(struct file *file, const char *buf, size_t count, loff_t *ppos)
static int sysfs_open_file(struct inode * inode, struct file * filp) static int sysfs_open_file(struct inode * inode, struct file * filp)
{ {
struct driver_dir_entry * dir; struct kobject * kobj;
int error = 0; int error = 0;
dir = (struct driver_dir_entry *)filp->f_dentry->d_parent->d_fsdata; kobj = filp->f_dentry->d_parent->d_fsdata;
if (dir) { if ((kobj = kobject_get(kobj))) {
struct attribute * attr = filp->f_dentry->d_fsdata; struct attribute * attr = filp->f_dentry->d_fsdata;
if (attr && dir->ops) { if (!attr)
if (dir->ops->open) error = -EINVAL;
error = dir->ops->open(dir); } else
goto Done;
}
}
error = -EINVAL; error = -EINVAL;
Done:
return error; return error;
} }
static int sysfs_release(struct inode * inode, struct file * filp) static int sysfs_release(struct inode * inode, struct file * filp)
{ {
struct driver_dir_entry * dir; struct kobject * kobj = filp->f_dentry->d_parent->d_fsdata;
dir = (struct driver_dir_entry *)filp->f_dentry->d_parent->d_fsdata; if (kobj)
if (dir->ops->close) kobject_put(kobj);
dir->ops->close(dir);
return 0; return 0;
} }
...@@ -371,6 +376,7 @@ static int __init sysfs_init(void) ...@@ -371,6 +376,7 @@ static int __init sysfs_init(void)
core_initcall(sysfs_init); core_initcall(sysfs_init);
static struct dentry * get_dentry(struct dentry * parent, const char * name) static struct dentry * get_dentry(struct dentry * parent, const char * name)
{ {
struct qstr qstr; struct qstr qstr;
...@@ -381,137 +387,160 @@ static struct dentry * get_dentry(struct dentry * parent, const char * name) ...@@ -381,137 +387,160 @@ static struct dentry * get_dentry(struct dentry * parent, const char * name)
return lookup_hash(&qstr,parent); return lookup_hash(&qstr,parent);
} }
/** /**
* sysfs_create_dir - create a directory in the filesystem * sysfs_create_dir - create a directory for an object.
* @entry: directory entry * @parent: parent parent object.
* @parent: parent directory entry * @kobj: object we're creating directory for.
*/ */
int
sysfs_create_dir(struct driver_dir_entry * entry, int sysfs_create_dir(struct kobject * kobj)
struct driver_dir_entry * parent)
{ {
struct dentry * dentry = NULL; struct dentry * dentry = NULL;
struct dentry * parent_dentry; struct dentry * parent;
int error = 0; int error = 0;
if (!entry) if (!kobj)
return -EINVAL; return -EINVAL;
parent_dentry = parent ? parent->dentry : NULL; if (kobj->parent)
parent = kobj->parent->dir.dentry;
if (!parent_dentry) else if (sysfs_mount && sysfs_mount->mnt_sb)
if (sysfs_mount && sysfs_mount->mnt_sb) parent = sysfs_mount->mnt_sb->s_root;
parent_dentry = sysfs_mount->mnt_sb->s_root; else
if (!parent_dentry)
return -EFAULT; return -EFAULT;
down(&parent_dentry->d_inode->i_sem); down(&parent->d_inode->i_sem);
dentry = get_dentry(parent_dentry,entry->name); dentry = get_dentry(parent,kobj->name);
if (!IS_ERR(dentry)) { if (!IS_ERR(dentry)) {
dentry->d_fsdata = (void *) entry; dentry->d_fsdata = (void *)kobj;
entry->dentry = dentry; kobj->dir.dentry = dentry;
error = sysfs_mkdir(parent_dentry->d_inode,dentry,entry->mode); error = sysfs_mkdir(parent->d_inode,dentry,
(S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO));
} else } else
error = PTR_ERR(dentry); error = PTR_ERR(dentry);
up(&parent_dentry->d_inode->i_sem); up(&parent->d_inode->i_sem);
return error; return error;
} }
/** /**
* sysfs_create_file - create a file * sysfs_create_file - create an attribute file for an object.
* @entry: structure describing the file * @kobj: object we're creating for.
* @parent: directory to create it in * @attr: atrribute descriptor.
*/ */
int
sysfs_create_file(struct attribute * entry, int sysfs_create_file(struct kobject * kobj, struct attribute * attr)
struct driver_dir_entry * parent)
{ {
struct dentry * dentry; struct dentry * dentry;
struct dentry * parent;
int error = 0; int error = 0;
if (!entry || !parent) if (!kobj || !attr)
return -EINVAL; return -EINVAL;
if (!parent->dentry) if (kobj->parent)
return -EINVAL; parent = kobj->parent->dir.dentry;
else
return -ENOENT;
down(&parent->dentry->d_inode->i_sem); down(&parent->d_inode->i_sem);
dentry = get_dentry(parent->dentry,entry->name); dentry = get_dentry(parent,attr->name);
if (!IS_ERR(dentry)) { if (!IS_ERR(dentry)) {
dentry->d_fsdata = (void *)entry; dentry->d_fsdata = (void *)attr;
error = sysfs_create(parent->dentry->d_inode,dentry,entry->mode); error = sysfs_create(parent->d_inode,dentry,attr->mode);
} else } else
error = PTR_ERR(dentry); error = PTR_ERR(dentry);
up(&parent->dentry->d_inode->i_sem); up(&parent->d_inode->i_sem);
return error; return error;
} }
/** /**
* sysfs_create_symlink - make a symlink * sysfs_create_symlink - make a symlink
* @parent: directory we're creating in * @kobj: object who's directory we're creating in.
* @entry: entry describing link * @name: name of the symlink.
* @target: place we're symlinking to * @target: path we're pointing to.
*
*/ */
int sysfs_create_symlink(struct driver_dir_entry * parent,
char * name, char * target) int sysfs_create_link(struct kobject * kobj, char * name, char * target)
{ {
struct dentry * dentry; struct dentry * dentry;
int error = 0; int error;
if (!parent || !parent->dentry) if (kobj) {
return -EINVAL; struct dentry * parent = kobj->dir.dentry;
down(&parent->dentry->d_inode->i_sem); down(&parent->d_inode->i_sem);
dentry = get_dentry(parent->dentry,name); dentry = get_dentry(parent,name);
if (!IS_ERR(dentry)) if (!IS_ERR(dentry))
error = sysfs_symlink(parent->dentry->d_inode,dentry,target); error = sysfs_symlink(parent->d_inode,dentry,target);
else else
error = PTR_ERR(dentry); error = PTR_ERR(dentry);
up(&parent->dentry->d_inode->i_sem); up(&parent->d_inode->i_sem);
} else
error = -EINVAL;
return error; return error;
} }
static void hash_and_remove(struct dentry * dir, const char * name)
{
struct dentry * victim;
down(&dir->d_inode->i_sem);
victim = get_dentry(dir,name);
if (!IS_ERR(victim)) {
/* make sure dentry is really there */
if (victim->d_inode &&
(victim->d_parent->d_inode == dir->d_inode)) {
sysfs_unlink(dir->d_inode,victim);
}
}
up(&dir->d_inode->i_sem);
}
/** /**
* sysfs_remove_file - exported file removal * sysfs_remove_file - remove an object attribute.
* @dir: directory the file supposedly resides in * @kobj: object we're acting for.
* @name: name of the file * @attr: attribute descriptor.
* *
* Try and find the file in the dir's list. * Hash the attribute name and kill the victim.
* If it's there, call __remove_file() (above) for the dentry.
*/ */
void sysfs_remove_file(struct driver_dir_entry * dir, const char * name)
void sysfs_remove_file(struct kobject * kobj, struct attribute * attr)
{ {
struct dentry * dentry; hash_and_remove(kobj->dir.dentry,attr->name);
}
if (!dir->dentry)
return;
down(&dir->dentry->d_inode->i_sem); /**
dentry = get_dentry(dir->dentry,name); * sysfs_remove_link - remove symlink in object's directory.
if (!IS_ERR(dentry)) { * @kobj: object we're acting for.
/* make sure dentry is really there */ * @name: name of the symlink to remove.
if (dentry->d_inode && */
(dentry->d_parent->d_inode == dir->dentry->d_inode)) {
sysfs_unlink(dir->dentry->d_inode,dentry); void sysfs_remove_link(struct kobject * kobj, char * name)
} {
} hash_and_remove(kobj->dir.dentry,name);
up(&dir->dentry->d_inode->i_sem);
} }
/** /**
* sysfs_remove_dir - exportable directory removal * sysfs_remove_dir - remove an object's directory.
* @dir: directory to remove * @kobj: object.
* *
* To make sure we don't orphan anyone, first remove * The only thing special about this is that we remove any files in
* all the children in the list, then do clean up the directory. * the directory before we remove the directory, and we've inlined
* what used to be sysfs_rmdir() below, instead of calling separately.
*/ */
void sysfs_remove_dir(struct driver_dir_entry * dir)
void sysfs_remove_dir(struct kobject * kobj)
{ {
struct list_head * node, * next; struct list_head * node, * next;
struct dentry * dentry = dir->dentry; struct dentry * dentry = kobj->dir.dentry;
struct dentry * parent; struct dentry * parent;
if (!dentry) if (!dentry)
...@@ -542,8 +571,9 @@ void sysfs_remove_dir(struct driver_dir_entry * dir) ...@@ -542,8 +571,9 @@ void sysfs_remove_dir(struct driver_dir_entry * dir)
} }
EXPORT_SYMBOL(sysfs_create_file); EXPORT_SYMBOL(sysfs_create_file);
EXPORT_SYMBOL(sysfs_create_symlink);
EXPORT_SYMBOL(sysfs_create_dir);
EXPORT_SYMBOL(sysfs_remove_file); EXPORT_SYMBOL(sysfs_remove_file);
EXPORT_SYMBOL(sysfs_create_link);
EXPORT_SYMBOL(sysfs_remove_link);
EXPORT_SYMBOL(sysfs_create_dir);
EXPORT_SYMBOL(sysfs_remove_dir); EXPORT_SYMBOL(sysfs_remove_dir);
MODULE_LICENSE("GPL"); MODULE_LICENSE("GPL");
include/linux/kobject.h
View file @ eda52025
...@@ -16,6 +16,7 @@ struct kobject { ...@@ -16,6 +16,7 @@ struct kobject {
atomic_t refcount; atomic_t refcount;
struct list_head entry; struct list_head entry;
struct kobject * parent; struct kobject * parent;
struct sysfs_dir dir;
}; };
extern void kobject_init(struct kobject *); extern void kobject_init(struct kobject *);
......
include/linux/sysfs.h
View file @ eda52025
...@@ -11,18 +11,15 @@ ...@@ -11,18 +11,15 @@
struct driver_dir_entry; struct driver_dir_entry;
struct attribute; struct attribute;
struct kobject;
struct sysfs_ops { struct sysfs_ops {
int (*open)(struct driver_dir_entry *); ssize_t (*show)(struct kobject *, struct attribute *,char *, size_t, loff_t);
int (*close)(struct driver_dir_entry *); ssize_t (*store)(struct kobject *,struct attribute *,const char *, size_t, loff_t);
ssize_t (*show)(struct driver_dir_entry *, struct attribute *,char *, size_t, loff_t);
ssize_t (*store)(struct driver_dir_entry *,struct attribute *,const char *, size_t, loff_t);
}; };
struct driver_dir_entry { struct sysfs_dir {
char * name;
struct dentry * dentry; struct dentry * dentry;
mode_t mode;
struct sysfs_ops * ops; struct sysfs_ops * ops;
}; };
...@@ -32,20 +29,21 @@ struct attribute { ...@@ -32,20 +29,21 @@ struct attribute {
}; };
extern int extern int
sysfs_create_dir(struct driver_dir_entry *, struct driver_dir_entry *); sysfs_create_dir(struct kobject *);
extern void extern void
sysfs_remove_dir(struct driver_dir_entry * entry); sysfs_remove_dir(struct kobject *);
extern int extern int
sysfs_create_file(struct attribute * attr, sysfs_create_file(struct kobject *, struct attribute *);
struct driver_dir_entry * parent);
extern void
sysfs_remove_file(struct kobject *, struct attribute *);
extern int extern int
sysfs_create_symlink(struct driver_dir_entry * parent, sysfs_create_link(struct kobject * kobj, char * name, char * target);
char * name, char * target);
extern void extern void
sysfs_remove_file(struct driver_dir_entry *, const char * name); sysfs_remove_link(struct kobject *, char * name);
#endif /* _SYSFS_H_ */ #endif /* _SYSFS_H_ */
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