5 files changed, 53 insertions, 50 deletions

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index e54e7e0033eb..3e4ce54d84ab 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -332,7 +332,7 @@ static inline bool inode_to_wb_is_valid(struct inode *inode)
  * holding either @inode->i_lock, @inode->i_mapping->tree_lock, or the
  * associated wb's list_lock.
  */
-static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
+static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
 {
 #ifdef CONFIG_LOCKDEP
         WARN_ON_ONCE(debug_locks &&
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 795634ee5aa5..6fc77d4dbdcd 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -337,9 +337,9 @@ extern void lock_release(struct lockdep_map *lock, int nested,
 /*
  * Same "read" as for lock_acquire(), except -1 means any.
  */
-extern int lock_is_held_type(struct lockdep_map *lock, int read);
+extern int lock_is_held_type(const struct lockdep_map *lock, int read);
 
-static inline int lock_is_held(struct lockdep_map *lock)
+static inline int lock_is_held(const struct lockdep_map *lock)
 {
         return lock_is_held_type(lock, -1);
 }
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 62be8966e837..33c1c698df09 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -92,7 +92,7 @@ void synchronize_srcu(struct srcu_struct *sp);
  * relies on normal RCU, it can be called from the CPU which
  * is in the idle loop from an RCU point of view or offline.
  */
-static inline int srcu_read_lock_held(struct srcu_struct *sp)
+static inline int srcu_read_lock_held(const struct srcu_struct *sp)
 {
         if (!debug_lockdep_rcu_enabled())
                 return 1;
@@ -101,7 +101,7 @@ static inline int srcu_read_lock_held(struct srcu_struct *sp)
 
 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
-static inline int srcu_read_lock_held(struct srcu_struct *sp)
+static inline int srcu_read_lock_held(const struct srcu_struct *sp)
 {
         return 1;
 }
diff --git a/include/net/sock.h b/include/net/sock.h
index 7a7b14e9628a..c4a424fe6fdd 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1445,10 +1445,8 @@ do {									\
 } while (0)
 
 #ifdef CONFIG_LOCKDEP
-static inline bool lockdep_sock_is_held(const struct sock *csk)
+static inline bool lockdep_sock_is_held(const struct sock *sk)
 {
-        struct sock *sk = (struct sock *)csk;
-
         return lockdep_is_held(&sk->sk_lock) ||
                lockdep_is_held(&sk->sk_lock.slock);
 }
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 521659044719..89b5f83f1969 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -648,18 +648,12 @@ static int count_matching_names(struct lock_class *new_class)
         return count + 1;
 }
 
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
 static inline struct lock_class *
-look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
+look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
 {
         struct lockdep_subclass_key *key;
         struct hlist_head *hash_head;
         struct lock_class *class;
-        bool is_static = false;
 
         if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
                 debug_locks_off();
@@ -672,24 +666,11 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
         }
 
         /*
-         * Static locks do not have their class-keys yet - for them the key
-         * is the lock object itself. If the lock is in the per cpu area,
-         * the canonical address of the lock (per cpu offset removed) is
-         * used.
+         * If it is not initialised then it has never been locked,
+         * so it won't be present in the hash table.
          */
-        if (unlikely(!lock->key)) {
-                unsigned long can_addr, addr = (unsigned long)lock;
-
-                if (__is_kernel_percpu_address(addr, &can_addr))
-                        lock->key = (void *)can_addr;
-                else if (__is_module_percpu_address(addr, &can_addr))
-                        lock->key = (void *)can_addr;
-                else if (static_obj(lock))
-                        lock->key = (void *)lock;
-                else
-                        return ERR_PTR(-EINVAL);
-                is_static = true;
-        }
+        if (unlikely(!lock->key))
+                return NULL;
 
         /*
          * NOTE: the class-key must be unique. For dynamic locks, a static
@@ -721,7 +702,35 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
                 }
         }
 
-        return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL);
+        return NULL;
+}
+
+/*
+ * Static locks do not have their class-keys yet - for them the key is
+ * the lock object itself. If the lock is in the per cpu area, the
+ * canonical address of the lock (per cpu offset removed) is used.
+ */
+static bool assign_lock_key(struct lockdep_map *lock)
+{
+        unsigned long can_addr, addr = (unsigned long)lock;
+
+        if (__is_kernel_percpu_address(addr, &can_addr))
+                lock->key = (void *)can_addr;
+        else if (__is_module_percpu_address(addr, &can_addr))
+                lock->key = (void *)can_addr;
+        else if (static_obj(lock))
+                lock->key = (void *)lock;
+        else {
+                /* Debug-check: all keys must be persistent! */
+                debug_locks_off();
+                pr_err("INFO: trying to register non-static key.\n");
+                pr_err("the code is fine but needs lockdep annotation.\n");
+                pr_err("turning off the locking correctness validator.\n");
+                dump_stack();
+                return false;
+        }
+
+        return true;
 }
 
 /*
@@ -739,18 +748,13 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
         DEBUG_LOCKS_WARN_ON(!irqs_disabled());
 
         class = look_up_lock_class(lock, subclass);
-        if (likely(!IS_ERR_OR_NULL(class)))
+        if (likely(class))
                 goto out_set_class_cache;
 
-        /*
-         * Debug-check: all keys must be persistent!
-         */
-        if (IS_ERR(class)) {
-                debug_locks_off();
-                printk("INFO: trying to register non-static key.\n");
-                printk("the code is fine but needs lockdep annotation.\n");
-                printk("turning off the locking correctness validator.\n");
-                dump_stack();
+        if (!lock->key) {
+                if (!assign_lock_key(lock))
+                        return NULL;
+        } else if (!static_obj(lock->key)) {
                 return NULL;
         }
 
@@ -3273,7 +3277,7 @@ print_lock_nested_lock_not_held(struct task_struct *curr,
         return 0;
 }
 
-static int __lock_is_held(struct lockdep_map *lock, int read);
+static int __lock_is_held(const struct lockdep_map *lock, int read);
 
 /*
  * This gets called for every mutex_lock*()/spin_lock*() operation.
@@ -3482,13 +3486,14 @@ print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
         return 0;
 }
 
-static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
+static int match_held_lock(const struct held_lock *hlock,
+                                        const struct lockdep_map *lock)
 {
         if (hlock->instance == lock)
                 return 1;
 
         if (hlock->references) {
-                struct lock_class *class = lock->class_cache[0];
+                const struct lock_class *class = lock->class_cache[0];
 
                 if (!class)
                         class = look_up_lock_class(lock, 0);
@@ -3499,7 +3504,7 @@ static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
                  * Clearly if the lock hasn't been acquired _ever_, we're not
                  * holding it either, so report failure.
                  */
-                if (IS_ERR_OR_NULL(class))
+                if (!class)
                         return 0;
 
                 /*
@@ -3724,7 +3729,7 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
         return 1;
 }
 
-static int __lock_is_held(struct lockdep_map *lock, int read)
+static int __lock_is_held(const struct lockdep_map *lock, int read)
 {
         struct task_struct *curr = current;
         int i;
@@ -3938,7 +3943,7 @@ void lock_release(struct lockdep_map *lock, int nested,
 }
 EXPORT_SYMBOL_GPL(lock_release);
 
-int lock_is_held_type(struct lockdep_map *lock, int read)
+int lock_is_held_type(const struct lockdep_map *lock, int read)
 {
         unsigned long flags;
         int ret = 0;
@@ -4295,7 +4300,7 @@ void lockdep_reset_lock(struct lockdep_map *lock)
                  * If the class exists we look it up and zap it:
                  */
                 class = look_up_lock_class(lock, j);
-                if (!IS_ERR_OR_NULL(class))
+                if (class)
                         zap_class(class);
         }
         /*