From 3007e997de91ec59af39a3f9c91595b31ae6e08b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 14 Jun 2007 04:27:23 +0900 Subject: sysfs: use sysfs_mutex to protect the sysfs_dirent tree As kobj sysfs dentries and inodes are gonna be made reclaimable, i_mutex can't be used to protect sysfs_dirent tree. Use sysfs_mutex globally instead. As the whole tree is protected with sysfs_mutex, there is no reason to keep sysfs_rename_sem. Drop it. While at it, add docbook comments to functions which require sysfs_mutex locking. Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/symlink.c | 51 ++++++++++++++++++++++++++------------------------- 1 file changed, 26 insertions(+), 25 deletions(-) (limited to 'fs/sysfs/symlink.c') diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c index cbd95a4109de..683316f0aa96 100644 --- a/fs/sysfs/symlink.c +++ b/fs/sysfs/symlink.c @@ -44,20 +44,6 @@ static void fill_object_path(struct sysfs_dirent *sd, char *buffer, int length) } } -static int sysfs_add_link(struct sysfs_dirent * parent_sd, const char * name, - struct sysfs_dirent * target_sd) -{ - struct sysfs_dirent * sd; - - sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK); - if (!sd) - return -ENOMEM; - - sd->s_elem.symlink.target_sd = target_sd; - sysfs_attach_dirent(sd, parent_sd, NULL); - return 0; -} - /** * sysfs_create_link - create symlink between two objects. * @kobj: object whose directory we're creating the link in. @@ -68,7 +54,8 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char { struct sysfs_dirent *parent_sd = NULL; struct sysfs_dirent *target_sd = NULL; - int error = -EEXIST; + struct sysfs_dirent *sd = NULL; + int error; BUG_ON(!name); @@ -78,8 +65,9 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char } else parent_sd = kobj->sd; + error = -EFAULT; if (!parent_sd) - return -EFAULT; + goto out_put; /* target->sd can go away beneath us but is protected with * sysfs_assoc_lock. Fetch target_sd from it. @@ -89,17 +77,30 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char target_sd = sysfs_get(target->sd); spin_unlock(&sysfs_assoc_lock); + error = -ENOENT; if (!target_sd) - return -ENOENT; + goto out_put; + + error = -ENOMEM; + sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK); + if (!sd) + goto out_put; + sd->s_elem.symlink.target_sd = target_sd; - mutex_lock(&parent_sd->s_dentry->d_inode->i_mutex); - if (!sysfs_find_dirent(parent_sd, name)) - error = sysfs_add_link(parent_sd, name, target_sd); - mutex_unlock(&parent_sd->s_dentry->d_inode->i_mutex); + mutex_lock(&sysfs_mutex); + error = -EEXIST; + if (sysfs_find_dirent(parent_sd, name)) + goto out_unlock; + sysfs_attach_dirent(sd, parent_sd, NULL); + mutex_unlock(&sysfs_mutex); - if (error) - sysfs_put(target_sd); + return 0; + out_unlock: + mutex_unlock(&sysfs_mutex); + out_put: + sysfs_put(target_sd); + sysfs_put(sd); return error; } @@ -144,9 +145,9 @@ static int sysfs_getlink(struct dentry *dentry, char * path) struct sysfs_dirent *target_sd = sd->s_elem.symlink.target_sd; int error; - down_read(&sysfs_rename_sem); + mutex_lock(&sysfs_mutex); error = sysfs_get_target_path(parent_sd, target_sd, path); - up_read(&sysfs_rename_sem); + mutex_unlock(&sysfs_mutex); return error; } -- cgit v1.2.3