1 files changed, 180 insertions, 64 deletions

diff --git a/kernel/gcov/fs.c b/kernel/gcov/fs.c
index ef3c3f88a7a..f83972b1656 100644
--- a/kernel/gcov/fs.c
+++ b/kernel/gcov/fs.c
@@ -33,10 +33,11 @@
  * @children: child nodes
  * @all: list head for list of all nodes
  * @parent: parent node
- * @info: associated profiling data structure if not a directory
- * @ghost: when an object file containing profiling data is unloaded we keep a
- *         copy of the profiling data here to allow collecting coverage data
- *         for cleanup code. Such a node is called a "ghost".
+ * @loaded_info: array of pointers to profiling data sets for loaded object
+ *   files.
+ * @num_loaded: number of profiling data sets for loaded object files.
+ * @unloaded_info: accumulated copy of profiling data sets for unloaded
+ *   object files. Used only when gcov_persist=1.
  * @dentry: main debugfs entry, either a directory or data file
  * @links: associated symbolic links
  * @name: data file basename
@@ -51,10 +52,11 @@ struct gcov_node {
         struct list_head children;
         struct list_head all;
         struct gcov_node *parent;
-        struct gcov_info *info;
-        struct gcov_info *ghost;
+        struct gcov_info **loaded_info;
+        struct gcov_info *unloaded_info;
         struct dentry *dentry;
         struct dentry **links;
+        int num_loaded;
         char name[0];
 };
 
@@ -136,16 +138,37 @@ static const struct seq_operations gcov_seq_ops = {
 };
 
 /*
- * Return the profiling data set for a given node. This can either be the
- * original profiling data structure or a duplicate (also called "ghost")
- * in case the associated object file has been unloaded.
+ * Return a profiling data set associated with the given node. This is
+ * either a data set for a loaded object file or a data set copy in case
+ * all associated object files have been unloaded.
  */
 static struct gcov_info *get_node_info(struct gcov_node *node)
 {
-        if (node->info)
-                return node->info;
+        if (node->num_loaded > 0)
+                return node->loaded_info[0];
 
-        return node->ghost;
+        return node->unloaded_info;
+}
+
+/*
+ * Return a newly allocated profiling data set which contains the sum of
+ * all profiling data associated with the given node.
+ */
+static struct gcov_info *get_accumulated_info(struct gcov_node *node)
+{
+        struct gcov_info *info;
+        int i = 0;
+
+        if (node->unloaded_info)
+                info = gcov_info_dup(node->unloaded_info);
+        else
+                info = gcov_info_dup(node->loaded_info[i++]);
+        if (!info)
+                return NULL;
+        for (; i < node->num_loaded; i++)
+                gcov_info_add(info, node->loaded_info[i]);
+
+        return info;
 }
 
 /*
@@ -163,9 +186,10 @@ static int gcov_seq_open(struct inode *inode, struct file *file)
         mutex_lock(&node_lock);
         /*
          * Read from a profiling data copy to minimize reference tracking
-         * complexity and concurrent access.
+         * complexity and concurrent access and to keep accumulating multiple
+         * profiling data sets associated with one node simple.
          */
-        info = gcov_info_dup(get_node_info(node));
+        info = get_accumulated_info(node);
         if (!info)
                 goto out_unlock;
         iter = gcov_iter_new(info);
@@ -225,12 +249,25 @@ static struct gcov_node *get_node_by_name(const char *name)
         return NULL;
 }
 
+/*
+ * Reset all profiling data associated with the specified node.
+ */
+static void reset_node(struct gcov_node *node)
+{
+        int i;
+
+        if (node->unloaded_info)
+                gcov_info_reset(node->unloaded_info);
+        for (i = 0; i < node->num_loaded; i++)
+                gcov_info_reset(node->loaded_info[i]);
+}
+
 static void remove_node(struct gcov_node *node);
 
 /*
  * write() implementation for gcov data files. Reset profiling data for the
- * associated file. If the object file has been unloaded (i.e. this is
- * a "ghost" node), remove the debug fs node as well.
+ * corresponding file. If all associated object files have been unloaded,
+ * remove the debug fs node as well.
  */
 static ssize_t gcov_seq_write(struct file *file, const char __user *addr,
                               size_t len, loff_t *pos)
@@ -245,10 +282,10 @@ static ssize_t gcov_seq_write(struct file *file, const char __user *addr,
         node = get_node_by_name(info->filename);
         if (node) {
                 /* Reset counts or remove node for unloaded modules. */
-                if (node->ghost)
+                if (node->num_loaded == 0)
                         remove_node(node);
                 else
-                        gcov_info_reset(node->info);
+                        reset_node(node);
         }
         /* Reset counts for open file. */
         gcov_info_reset(info);
@@ -378,7 +415,10 @@ static void init_node(struct gcov_node *node, struct gcov_info *info,
         INIT_LIST_HEAD(&node->list);
         INIT_LIST_HEAD(&node->children);
         INIT_LIST_HEAD(&node->all);
-        node->info = info;
+        if (node->loaded_info) {
+                node->loaded_info[0] = info;
+                node->num_loaded = 1;
+        }
         node->parent = parent;
         if (name)
                 strcpy(node->name, name);
@@ -394,9 +434,13 @@ static struct gcov_node *new_node(struct gcov_node *parent,
         struct gcov_node *node;
 
         node = kzalloc(sizeof(struct gcov_node) + strlen(name) + 1, GFP_KERNEL);
-        if (!node) {
-                pr_warning("out of memory\n");
-                return NULL;
+        if (!node)
+                goto err_nomem;
+        if (info) {
+                node->loaded_info = kcalloc(1, sizeof(struct gcov_info *),
+                                           GFP_KERNEL);
+                if (!node->loaded_info)
+                        goto err_nomem;
         }
         init_node(node, info, name, parent);
         /* Differentiate between gcov data file nodes and directory nodes. */
@@ -416,6 +460,11 @@ static struct gcov_node *new_node(struct gcov_node *parent,
         list_add(&node->all, &all_head);
 
         return node;
+
+err_nomem:
+        kfree(node);
+        pr_warning("out of memory\n");
+        return NULL;
 }
 
 /* Remove symbolic links associated with node. */
@@ -441,8 +490,9 @@ static void release_node(struct gcov_node *node)
         list_del(&node->all);
         debugfs_remove(node->dentry);
         remove_links(node);
-        if (node->ghost)
-                gcov_info_free(node->ghost);
+        kfree(node->loaded_info);
+        if (node->unloaded_info)
+                gcov_info_free(node->unloaded_info);
         kfree(node);
 }
 
@@ -477,7 +527,7 @@ static struct gcov_node *get_child_by_name(struct gcov_node *parent,
 
 /*
  * write() implementation for reset file. Reset all profiling data to zero
- * and remove ghost nodes.
+ * and remove nodes for which all associated object files are unloaded.