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-rw-r--r--fs/sysfs/dir.c14
-rw-r--r--fs/sysfs/sysfs.h15
2 files changed, 27 insertions, 2 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index f05f2303a8b..699f371b9f1 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -106,8 +106,10 @@ static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
return NULL;
t = atomic_cmpxchg(&sd->s_active, v, v + 1);
- if (likely(t == v))
+ if (likely(t == v)) {
+ rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
return sd;
+ }
if (t < 0)
return NULL;
@@ -130,6 +132,7 @@ static void sysfs_put_active(struct sysfs_dirent *sd)
if (unlikely(!sd))
return;
+ rwsem_release(&sd->dep_map, 1, _RET_IP_);
v = atomic_dec_return(&sd->s_active);
if (likely(v != SD_DEACTIVATED_BIAS))
return;
@@ -194,15 +197,21 @@ static void sysfs_deactivate(struct sysfs_dirent *sd)
BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
sd->s_sibling = (void *)&wait;
+ rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
/* atomic_add_return() is a mb(), put_active() will always see
* the updated sd->s_sibling.
*/
v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
- if (v != SD_DEACTIVATED_BIAS)
+ if (v != SD_DEACTIVATED_BIAS) {
+ lock_contended(&sd->dep_map, _RET_IP_);
wait_for_completion(&wait);
+ }
sd->s_sibling = NULL;
+
+ lock_acquired(&sd->dep_map, _RET_IP_);
+ rwsem_release(&sd->dep_map, 1, _RET_IP_);
}
static int sysfs_alloc_ino(ino_t *pino)
@@ -345,6 +354,7 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
atomic_set(&sd->s_count, 1);
atomic_set(&sd->s_active, 0);
+ sysfs_dirent_init_lockdep(sd);
sd->s_name = name;
sd->s_mode = mode;
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index ca52e7b9d8f..cdd9377a6e0 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -8,6 +8,7 @@
* This file is released under the GPLv2.
*/
+#include <linux/lockdep.h>
#include <linux/fs.h>
struct sysfs_open_dirent;
@@ -50,6 +51,9 @@ struct sysfs_inode_attrs {
struct sysfs_dirent {
atomic_t s_count;
atomic_t s_active;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
struct sysfs_dirent *s_parent;
struct sysfs_dirent *s_sibling;
const char *s_name;
@@ -84,6 +88,17 @@ static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
return sd->s_flags & SYSFS_TYPE_MASK;
}
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define sysfs_dirent_init_lockdep(sd) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ lockdep_init_map(&sd->dep_map, "s_active", &__key, 0); \
+} while(0)
+#else
+#define sysfs_dirent_init_lockdep(sd) do {} while(0)
+#endif
+
/*
* Context structure to be used while adding/removing nodes.
*/