Commit aecdceda authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman

sysfs: implement kobj_sysfs_assoc_lock

kobj->dentry can go away anytime unless the user controls when the
associated sysfs node is deleted.  This patch implements
kobj_sysfs_assoc_lock which protects kobj->dentry.  This will be used
to maintain kobj based API when converting sysfs to use sysfs_dirent
tree instead of dentry/kobject.

Note that this lock belongs to kobject/driver-model not sysfs.  Once
sysfs is converted to not use kobject in its interface, this can be
removed from sysfs.

This is in preparation of object reference simplification.
Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 3e519038
......@@ -15,6 +15,7 @@
DECLARE_RWSEM(sysfs_rename_sem);
spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED;
spinlock_t kobj_sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;
static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
static DEFINE_IDA(sysfs_ino_ida);
......@@ -426,8 +427,13 @@ static void __sysfs_remove_dir(struct dentry *dentry)
void sysfs_remove_dir(struct kobject * kobj)
{
__sysfs_remove_dir(kobj->dentry);
struct dentry *d = kobj->dentry;
spin_lock(&kobj_sysfs_assoc_lock);
kobj->dentry = NULL;
spin_unlock(&kobj_sysfs_assoc_lock);
__sysfs_remove_dir(d);
}
int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
......
......@@ -62,6 +62,7 @@ extern void sysfs_drop_dentry(struct sysfs_dirent *sd, struct dentry *parent);
extern int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
extern spinlock_t sysfs_lock;
extern spinlock_t kobj_sysfs_assoc_lock;
extern struct rw_semaphore sysfs_rename_sem;
extern struct super_block * sysfs_sb;
extern const struct file_operations sysfs_dir_operations;
......
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