diff options
Diffstat (limited to '')
-rw-r--r-- | fs/sysfs/file.c | 380 |
1 files changed, 174 insertions, 206 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index b502c7197ec0..3e1cc062a740 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -50,29 +50,15 @@ static struct sysfs_ops subsys_sysfs_ops = { .store = subsys_attr_store, }; -/** - * add_to_collection - add buffer to a collection - * @buffer: buffer to be added - * @node: inode of set to add to - */ - -static inline void -add_to_collection(struct sysfs_buffer *buffer, struct inode *node) -{ - struct sysfs_buffer_collection *set = node->i_private; - - mutex_lock(&node->i_mutex); - list_add(&buffer->associates, &set->associates); - mutex_unlock(&node->i_mutex); -} - -static inline void -remove_from_collection(struct sysfs_buffer *buffer, struct inode *node) -{ - mutex_lock(&node->i_mutex); - list_del(&buffer->associates); - mutex_unlock(&node->i_mutex); -} +struct sysfs_buffer { + size_t count; + loff_t pos; + char * page; + struct sysfs_ops * ops; + struct semaphore sem; + int needs_read_fill; + int event; +}; /** * fill_read_buffer - allocate and fill buffer from object. @@ -87,9 +73,8 @@ remove_from_collection(struct sysfs_buffer *buffer, struct inode *node) */ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer) { - struct sysfs_dirent * sd = dentry->d_fsdata; - struct attribute * attr = to_attr(dentry); - struct kobject * kobj = to_kobj(dentry->d_parent); + struct sysfs_dirent *attr_sd = dentry->d_fsdata; + struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj; struct sysfs_ops * ops = buffer->ops; int ret = 0; ssize_t count; @@ -99,8 +84,15 @@ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer if (!buffer->page) return -ENOMEM; - buffer->event = atomic_read(&sd->s_event); - count = ops->show(kobj,attr,buffer->page); + /* need attr_sd for attr and ops, its parent for kobj */ + if (!sysfs_get_active_two(attr_sd)) + return -ENODEV; + + buffer->event = atomic_read(&attr_sd->s_event); + count = ops->show(kobj, attr_sd->s_elem.attr.attr, buffer->page); + + sysfs_put_active_two(attr_sd); + BUG_ON(count > (ssize_t)PAGE_SIZE); if (count >= 0) { buffer->needs_read_fill = 0; @@ -138,10 +130,7 @@ sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) down(&buffer->sem); if (buffer->needs_read_fill) { - if (buffer->orphaned) - retval = -ENODEV; - else - retval = fill_read_buffer(file->f_path.dentry,buffer); + retval = fill_read_buffer(file->f_path.dentry,buffer); if (retval) goto out; } @@ -196,14 +185,23 @@ fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t * passing the buffer that we acquired in fill_write_buffer(). */ -static int +static int flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count) { - struct attribute * attr = to_attr(dentry); - struct kobject * kobj = to_kobj(dentry->d_parent); + struct sysfs_dirent *attr_sd = dentry->d_fsdata; + struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj; struct sysfs_ops * ops = buffer->ops; + int rc; + + /* need attr_sd for attr and ops, its parent for kobj */ + if (!sysfs_get_active_two(attr_sd)) + return -ENODEV; + + rc = ops->store(kobj, attr_sd->s_elem.attr.attr, buffer->page, count); + + sysfs_put_active_two(attr_sd); - return ops->store(kobj,attr,buffer->page,count); + return rc; } @@ -231,37 +229,26 @@ sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t ssize_t len; down(&buffer->sem); - if (buffer->orphaned) { - len = -ENODEV; - goto out; - } len = fill_write_buffer(buffer, buf, count); if (len > 0) len = flush_write_buffer(file->f_path.dentry, buffer, len); if (len > 0) *ppos += len; -out: up(&buffer->sem); return len; } static int sysfs_open_file(struct inode *inode, struct file *file) { - struct kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent); - struct attribute * attr = to_attr(file->f_path.dentry); - struct sysfs_buffer_collection *set; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj; struct sysfs_buffer * buffer; struct sysfs_ops * ops = NULL; - int error = 0; - - if (!kobj || !attr) - goto Einval; + int error; - /* Grab the module reference for this attribute if we have one */ - if (!try_module_get(attr->owner)) { - error = -ENODEV; - goto Done; - } + /* need attr_sd for attr and ops, its parent for kobj */ + if (!sysfs_get_active_two(attr_sd)) + return -ENODEV; /* if the kobject has no ktype, then we assume that it is a subsystem * itself, and use ops for it. @@ -273,33 +260,21 @@ static int sysfs_open_file(struct inode *inode, struct file *file) else ops = &subsys_sysfs_ops; + error = -EACCES; + /* No sysfs operations, either from having no subsystem, * or the subsystem have no operations. */ if (!ops) - goto Eaccess; - - /* make sure we have a collection to add our buffers to */ - mutex_lock(&inode->i_mutex); - if (!(set = inode->i_private)) { - if (!(set = inode->i_private = kmalloc(sizeof(struct sysfs_buffer_collection), GFP_KERNEL))) { - error = -ENOMEM; - goto Done; - } else { - INIT_LIST_HEAD(&set->associates); - } - } - mutex_unlock(&inode->i_mutex); + goto err_out; /* File needs write support. * The inode's perms must say it's ok, * and we must have a store method. */ if (file->f_mode & FMODE_WRITE) { - if (!(inode->i_mode & S_IWUGO) || !ops->store) - goto Eaccess; - + goto err_out; } /* File needs read support. @@ -308,48 +283,38 @@ static int sysfs_open_file(struct inode *inode, struct file *file) */ if (file->f_mode & FMODE_READ) { if (!(inode->i_mode & S_IRUGO) || !ops->show) - goto Eaccess; + goto err_out; } /* No error? Great, allocate a buffer for the file, and store it * it in file->private_data for easy access. */ + error = -ENOMEM; buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL); - if (buffer) { - INIT_LIST_HEAD(&buffer->associates); - init_MUTEX(&buffer->sem); - buffer->needs_read_fill = 1; - buffer->ops = ops; - add_to_collection(buffer, inode); - file->private_data = buffer; - } else - error = -ENOMEM; - goto Done; - - Einval: - error = -EINVAL; - goto Done; - Eaccess: - error = -EACCES; - module_put(attr->owner); - Done: - if (error) - kobject_put(kobj); + if (!buffer) + goto err_out; + + init_MUTEX(&buffer->sem); + buffer->needs_read_fill = 1; + buffer->ops = ops; + file->private_data = buffer; + + /* open succeeded, put active references and pin attr_sd */ + sysfs_put_active_two(attr_sd); + sysfs_get(attr_sd); + return 0; + + err_out: + sysfs_put_active_two(attr_sd); return error; } static int sysfs_release(struct inode * inode, struct file * filp) { - struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent); - struct attribute * attr = to_attr(filp->f_path.dentry); - struct module * owner = attr->owner; - struct sysfs_buffer * buffer = filp->private_data; + struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; + struct sysfs_buffer *buffer = filp->private_data; - if (buffer) - remove_from_collection(buffer, inode); - kobject_put(kobj); - /* After this point, attr should not be accessed. */ - module_put(owner); + sysfs_put(attr_sd); if (buffer) { if (buffer->page) @@ -376,57 +341,43 @@ static int sysfs_release(struct inode * inode, struct file * filp) static unsigned int sysfs_poll(struct file *filp, poll_table *wait) { struct sysfs_buffer * buffer = filp->private_data; - struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent); - struct sysfs_dirent * sd = filp->f_path.dentry->d_fsdata; - int res = 0; + struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; + struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj; + + /* need parent for the kobj, grab both */ + if (!sysfs_get_active_two(attr_sd)) + goto trigger; poll_wait(filp, &kobj->poll, wait); - if (buffer->event != atomic_read(&sd->s_event)) { - res = POLLERR|POLLPRI; - buffer->needs_read_fill = 1; - } + sysfs_put_active_two(attr_sd); - return res; -} + if (buffer->event != atomic_read(&attr_sd->s_event)) + goto trigger; + return 0; -static struct dentry *step_down(struct dentry *dir, const char * name) -{ - struct dentry * de; - - if (dir == NULL || dir->d_inode == NULL) - return NULL; - - mutex_lock(&dir->d_inode->i_mutex); - de = lookup_one_len(name, dir, strlen(name)); - mutex_unlock(&dir->d_inode->i_mutex); - dput(dir); - if (IS_ERR(de)) - return NULL; - if (de->d_inode == NULL) { - dput(de); - return NULL; - } - return de; + trigger: + buffer->needs_read_fill = 1; + return POLLERR|POLLPRI; } -void sysfs_notify(struct kobject * k, char *dir, char *attr) +void sysfs_notify(struct kobject *k, char *dir, char *attr) { - struct dentry *de = k->dentry; - if (de) - dget(de); - if (de && dir) - de = step_down(de, dir); - if (de && attr) - de = step_down(de, attr); - if (de) { - struct sysfs_dirent * sd = de->d_fsdata; - if (sd) - atomic_inc(&sd->s_event); + struct sysfs_dirent *sd = k->sd; + + mutex_lock(&sysfs_mutex); + + if (sd && dir) + sd = sysfs_find_dirent(sd, dir); + if (sd && attr) + sd = sysfs_find_dirent(sd, attr); + if (sd) { + atomic_inc(&sd->s_event); wake_up_interruptible(&k->poll); - dput(de); } + + mutex_unlock(&sysfs_mutex); } EXPORT_SYMBOL_GPL(sysfs_notify); @@ -440,19 +391,31 @@ const struct file_operations sysfs_file_operations = { }; -int sysfs_add_file(struct dentry * dir, const struct attribute * attr, int type) +int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, + int type) { - struct sysfs_dirent * parent_sd = dir->d_fsdata; umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG; - int error = -EEXIST; + struct sysfs_addrm_cxt acxt; + struct sysfs_dirent *sd; + + sd = sysfs_new_dirent(attr->name, mode, type); + if (!sd) + return -ENOMEM; + sd->s_elem.attr.attr = (void *)attr; - mutex_lock(&dir->d_inode->i_mutex); - if (!sysfs_dirent_exist(parent_sd, attr->name)) - error = sysfs_make_dirent(parent_sd, NULL, (void *)attr, - mode, type); - mutex_unlock(&dir->d_inode->i_mutex); + sysfs_addrm_start(&acxt, dir_sd); - return error; + if (!sysfs_find_dirent(dir_sd, attr->name)) { + sysfs_add_one(&acxt, sd); + sysfs_link_sibling(sd); + } + + if (!sysfs_addrm_finish(&acxt)) { + sysfs_put(sd); + return -EEXIST; + } + + return 0; } @@ -464,9 +427,9 @@ int sysfs_add_file(struct dentry * dir, const struct attribute * attr, int type) int sysfs_create_file(struct kobject * kobj, const struct attribute * attr) { - BUG_ON(!kobj || !kobj->dentry || !attr); + BUG_ON(!kobj || !kobj->sd || !attr); - return sysfs_add_file(kobj->dentry, attr, SYSFS_KOBJ_ATTR); + return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR); } @@ -480,16 +443,16 @@ int sysfs_create_file(struct kobject * kobj, const struct attribute * attr) int sysfs_add_file_to_group(struct kobject *kobj, const struct attribute *attr, const char *group) { - struct dentry *dir; + struct sysfs_dirent *dir_sd; int error; - dir = lookup_one_len(group, kobj->dentry, strlen(group)); - if (IS_ERR(dir)) - error = PTR_ERR(dir); - else { - error = sysfs_add_file(dir, attr, SYSFS_KOBJ_ATTR); - dput(dir); - } + dir_sd = sysfs_get_dirent(kobj->sd, group); + if (!dir_sd) + return -ENOENT; + + error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); + sysfs_put(dir_sd); + return error; } EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); @@ -502,30 +465,31 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); */ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr) { - struct dentry * dir = kobj->dentry; - struct dentry * victim; - int res = -ENOENT; - - mutex_lock(&dir->d_inode->i_mutex); - victim = lookup_one_len(attr->name, dir, strlen(attr->name)); - if (!IS_ERR(victim)) { - /* make sure dentry is really there */ - if (victim->d_inode && - (victim->d_parent->d_inode == dir->d_inode)) { - victim->d_inode->i_mtime = CURRENT_TIME; - fsnotify_modify(victim); - res = 0; - } else - d_drop(victim); - - /** - * Drop the reference acquired from lookup_one_len() above. - */ - dput(victim); + struct sysfs_dirent *victim_sd = NULL; + struct dentry *victim = NULL; + int rc; + + rc = -ENOENT; + victim_sd = sysfs_get_dirent(kobj->sd, attr->name); + if (!victim_sd) + goto out; + + victim = sysfs_get_dentry(victim_sd); + if (IS_ERR(victim)) { + rc = PTR_ERR(victim); + victim = NULL; + goto out; } - mutex_unlock(&dir->d_inode->i_mutex); - return res; + mutex_lock(&victim->d_inode->i_mutex); + victim->d_inode->i_mtime = CURRENT_TIME; + fsnotify_modify(victim); + mutex_unlock(&victim->d_inode->i_mutex); + rc = 0; + out: + dput(victim); + sysfs_put(victim_sd); + return rc; } @@ -538,30 +502,34 @@ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr) */ int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode) { - struct dentry *dir = kobj->dentry; - struct dentry *victim; + struct sysfs_dirent *victim_sd = NULL; + struct dentry *victim = NULL; struct inode * inode; struct iattr newattrs; - int res = -ENOENT; - - mutex_lock(&dir->d_inode->i_mutex); - victim = lookup_one_len(attr->name, dir, strlen(attr->name)); - if (!IS_ERR(victim)) { - if (victim->d_inode && - (victim->d_parent->d_inode == dir->d_inode)) { - inode = victim->d_inode; - mutex_lock(&inode->i_mutex); - newattrs.ia_mode = (mode & S_IALLUGO) | - (inode->i_mode & ~S_IALLUGO); - newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; - res = notify_change(victim, &newattrs); - mutex_unlock(&inode->i_mutex); - } - dput(victim); + int rc; + + rc = -ENOENT; + victim_sd = sysfs_get_dirent(kobj->sd, attr->name); + if (!victim_sd) + goto out; + + victim = sysfs_get_dentry(victim_sd); + if (IS_ERR(victim)) { + rc = PTR_ERR(victim); + victim = NULL; + goto out; } - mutex_unlock(&dir->d_inode->i_mutex); - return res; + inode = victim->d_inode; + mutex_lock(&inode->i_mutex); + newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); + newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; + rc = notify_change(victim, &newattrs); + mutex_unlock(&inode->i_mutex); + out: + dput(victim); + sysfs_put(victim_sd); + return rc; } EXPORT_SYMBOL_GPL(sysfs_chmod_file); @@ -576,7 +544,7 @@ EXPORT_SYMBOL_GPL(sysfs_chmod_file); void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr) { - sysfs_hash_and_remove(kobj->dentry, attr->name); + sysfs_hash_and_remove(kobj->sd, attr->name); } @@ -589,12 +557,12 @@ void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr) void sysfs_remove_file_from_group(struct kobject *kobj, const struct attribute *attr, const char *group) { - struct dentry *dir; + struct sysfs_dirent *dir_sd; - dir = lookup_one_len(group, kobj->dentry, strlen(group)); - if (!IS_ERR(dir)) { - sysfs_hash_and_remove(dir, attr->name); - dput(dir); + dir_sd = sysfs_get_dirent(kobj->sd, group); + if (dir_sd) { + sysfs_hash_and_remove(dir_sd, attr->name); + sysfs_put(dir_sd); } } EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); |