[PATCH 55/61] sysfs: consolidate sysfs spinlocks

Greg Kroah-Hartman
2007-07-11T23:59:25Z

Replace sysfs_lock and kobj_sysfs_assoc_lock with sysfs_assoc_lock.
sysfs_lock was originally to be used to protect sysfs_dirent tree but
mutex seems better choice, so there is no reason to keep sysfs_lock
separate. Merge the two spinlocks into one.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/sysfs/dir.c | 19 +++++++++----------
fs/sysfs/inode.c | 16 ++++++++--------
fs/sysfs/symlink.c | 6 +++---
fs/sysfs/sysfs.h | 3 +--
4 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 31b6cf3..1b56434 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -15,8 +15,7 @@
#include "sysfs.h"

DECLARE_RWSEM(sysfs_rename_sem);
-spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED;
-spinlock_t kobj_sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;
+spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;

static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
static DEFINE_IDA(sysfs_ino_ida);
@@ -236,10 +235,10 @@ static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
struct sysfs_dirent * sd = dentry->d_fsdata;

if (sd) {
- /* sd->s_dentry is protected with sysfs_lock. This
- * allows sysfs_drop_dentry() to dereference it.
+ /* sd->s_dentry is protected with sysfs_assoc_lock.
+ * This allows sysfs_drop_dentry() to dereference it.
*/
- spin_lock(&sysfs_lock);
+ spin_lock(&sysfs_assoc_lock);

/* The dentry might have been deleted or another
* lookup could have happened updating sd->s_dentry to
@@ -248,7 +247,7 @@ static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
*/
if (sd->s_dentry == dentry)
sd->s_dentry = NULL;
- spin_unlock(&sysfs_lock);
+ spin_unlock(&sysfs_assoc_lock);
sysfs_put(sd);
}
iput(inode);
@@ -298,9 +297,9 @@ static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry)
dentry->d_fsdata = sysfs_get(sd);

/* protect sd->s_dentry against sysfs_d_iput */
- spin_lock(&sysfs_lock);
+ spin_lock(&sysfs_assoc_lock);
sd->s_dentry = dentry;
- spin_unlock(&sysfs_lock);
+ spin_unlock(&sysfs_assoc_lock);

d_rehash(dentry);
}
@@ -603,9 +602,9 @@ void sysfs_remove_dir(struct kobject * kobj)
{
struct sysfs_dirent *sd = kobj->sd;

- spin_lock(&kobj_sysfs_assoc_lock);
+ spin_lock(&sysfs_assoc_lock);
kobj->sd = NULL;
- spin_unlock(&kobj_sysfs_assoc_lock);
+ spin_unlock(&sysfs_assoc_lock);

__sysfs_remove_dir(sd);
}
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 1be8537..e4c2393 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -211,11 +211,11 @@ void sysfs_instantiate(struct dentry *dentry, struct inode *inode)
* parent on entry to this function such that it can't be looked
* up anymore.
*
- * @sd->s_dentry which is protected with sysfs_lock points to the
- * currently associated dentry but we're not holding a reference
- * to it and racing with dput(). Grab dcache_lock and verify
- * dentry before dropping it. If @sd->s_dentry is NULL or dput()
- * beats us, no need to bother.
+ * @sd->s_dentry which is protected with sysfs_assoc_lock points
+ * to the currently associated dentry but we're not holding a
+ * reference to it and racing with dput(). Grab dcache_lock and
+ * verify dentry before dropping it. If @sd->s_dentry is NULL or
+ * dput() beats us, no need to bother.
*/
void sysfs_drop_dentry(struct sysfs_dirent *sd)
{
@@ -224,9 +224,9 @@ void sysfs_drop_dentry(struct sysfs_dirent *sd)
struct inode *inode;

/* We're not holding a reference to ->s_dentry dentry but the
- * field will stay valid as long as sysfs_lock is held.
+ * field will stay valid as long as sysfs_assoc_lock is held.
*/
- spin_lock(&sysfs_lock);
+ spin_lock(&sysfs_assoc_lock);
spin_lock(&dcache_lock);

/* drop dentry if it's there and dput() didn't kill it yet */
@@ -238,7 +238,7 @@ void sysfs_drop_dentry(struct sysfs_dirent *sd)
}

spin_unlock(&dcache_lock);
- spin_unlock(&sysfs_lock);
+ spin_unlock(&sysfs_assoc_lock);

dput(dentry);
/* XXX: unpin if directory, this will go away soon */
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 43cc522..cbd95a4 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -82,12 +82,12 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
return -EFAULT;

/* target->sd can go away beneath us but is protected with
- * kobj_sysfs_assoc_lock. Fetch target_sd from it.
+ * sysfs_assoc_lock. Fetch target_sd from it.
*/
- spin_lock(&kobj_sysfs_assoc_lock);
+ spin_lock(&sysfs_assoc_lock);
if (target->sd)
target_sd = sysfs_get(target->sd);
- spin_unlock(&kobj_sysfs_assoc_lock);
+ spin_unlock(&sysfs_assoc_lock);

if (!target_sd)
return -ENOENT;
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 27a5f4b..4572677 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -81,8 +81,7 @@ extern void sysfs_remove_subdir(struct sysfs_dirent *sd);
extern void sysfs_drop_dentry(struct sysfs_dirent *sd);
extern int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);

-extern spinlock_t sysfs_lock;
-extern spinlock_t kobj_sysfs_assoc_lock;
+extern spinlock_t sysfs_assoc_lock;
extern struct rw_semaphore sysfs_rename_sem;
extern struct super_block * sysfs_sb;
extern const struct file_operations sysfs_dir_operations;
--
1.5.2.2