ftrace: Balance records when updating the hash

[mv-sheeva.git] / kernel / trace / ftrace.c

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index df93392aad89a29a0d6f805960981c48c0c4ba88..853f6f0a4b4a02bda3a0b2f2fa330b14718f9dfb 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1170,8 +1170,14 @@ alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
        return NULL;
 }
 
+static void
+ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
+static void
+ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
+
 static int
-ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
+ftrace_hash_move(struct ftrace_ops *ops, int enable,
+                struct ftrace_hash **dst, struct ftrace_hash *src)
 {
        struct ftrace_func_entry *entry;
        struct hlist_node *tp, *tn;
@@ -1181,8 +1187,15 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
        unsigned long key;
        int size = src->count;
        int bits = 0;
+       int ret;
        int i;
 
+       /*
+        * Remove the current set, update the hash and add
+        * them back.
+        */
+       ftrace_hash_rec_disable(ops, enable);
+
        /*
         * If the new source is empty, just free dst and assign it
         * the empty_hash.
@@ -1203,9 +1216,10 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
        if (bits > FTRACE_HASH_MAX_BITS)
                bits = FTRACE_HASH_MAX_BITS;
 
+       ret = -ENOMEM;
        new_hash = alloc_ftrace_hash(bits);
        if (!new_hash)
-               return -ENOMEM;
+               goto out;
 
        size = 1 << src->size_bits;
        for (i = 0; i < size; i++) {
@@ -1224,7 +1238,16 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
        rcu_assign_pointer(*dst, new_hash);
        free_ftrace_hash_rcu(old_hash);
 
-       return 0;
+       ret = 0;
+ out:
+       /*
+        * Enable regardless of ret:
+        *  On success, we enable the new hash.
+        *  On failure, we re-enable the original hash.
+        */
+       ftrace_hash_rec_enable(ops, enable);
+
+       return ret;
 }
 
 /*
@@ -2845,7 +2868,7 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
                ftrace_match_records(hash, buf, len);
 
        mutex_lock(&ftrace_lock);
-       ret = ftrace_hash_move(orig_hash, hash);
+       ret = ftrace_hash_move(ops, enable, orig_hash, hash);
        mutex_unlock(&ftrace_lock);
 
        mutex_unlock(&ftrace_regex_lock);
@@ -3028,18 +3051,12 @@ ftrace_regex_release(struct inode *inode, struct file *file)
                        orig_hash = &iter->ops->notrace_hash;
 
                mutex_lock(&ftrace_lock);
-               /*
-                * Remove the current set, update the hash and add
-                * them back.
-                */
-               ftrace_hash_rec_disable(iter->ops, filter_hash);
-               ret = ftrace_hash_move(orig_hash, iter->hash);
-               if (!ret) {
-                       ftrace_hash_rec_enable(iter->ops, filter_hash);
-                       if (iter->ops->flags & FTRACE_OPS_FL_ENABLED
-                           && ftrace_enabled)
-                               ftrace_run_update_code(FTRACE_ENABLE_CALLS);
-               }
+               ret = ftrace_hash_move(iter->ops, filter_hash,
+                                      orig_hash, iter->hash);
+               if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
+                   && ftrace_enabled)
+                       ftrace_run_update_code(FTRACE_ENABLE_CALLS);
+
                mutex_unlock(&ftrace_lock);
        }
        free_ftrace_hash(iter->hash);