gcov: move gcov structs definitions to a gcc version specific file

Since also the gcov structures(gcov_info, gcov_fn_info, gcov_ctr_info) can
change between gcc releases, as shown in gcc 4.7, they cannot be defined
in a common header and need to be moved to a specific gcc implemention
file.  This also requires to make the gcov_info structure opaque for the
common code and to introduce simple helpers for accessing data inside
gcov_info.

Signed-off-by: Frantisek Hrbata <fhrbata@redhat.com>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Gospodarek <agospoda@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/gcov/base.c b/kernel/gcov/base.c
index 9b22d03..912576a 100644
--- a/kernel/gcov/base.c
+++ b/kernel/gcov/base.c
@@ -20,7 +20,6 @@
 #include <linux/mutex.h>
 #include "gcov.h"
 
-static struct gcov_info *gcov_info_head;
 static int gcov_events_enabled;
 static DEFINE_MUTEX(gcov_lock);
 
@@ -34,7 +33,7 @@
 
 	mutex_lock(&gcov_lock);
 	if (gcov_version == 0) {
-		gcov_version = info->version;
+		gcov_version = gcov_info_version(info);
 		/*
 		 * Printing gcc's version magic may prove useful for debugging
 		 * incompatibility reports.
@@ -45,8 +44,7 @@
 	 * Add new profiling data structure to list and inform event
 	 * listener.
 	 */
-	info->next = gcov_info_head;
-	gcov_info_head = info;
+	gcov_info_link(info);
 	if (gcov_events_enabled)
 		gcov_event(GCOV_ADD, info);
 	mutex_unlock(&gcov_lock);
@@ -91,13 +89,15 @@
  */
 void gcov_enable_events(void)
 {
-	struct gcov_info *info;
+	struct gcov_info *info = NULL;
 
 	mutex_lock(&gcov_lock);
 	gcov_events_enabled = 1;
+
 	/* Perform event callback for previously registered entries. */
-	for (info = gcov_info_head; info; info = info->next)
+	while ((info = gcov_info_next(info)))
 		gcov_event(GCOV_ADD, info);
+
 	mutex_unlock(&gcov_lock);
 }
 
@@ -112,25 +112,23 @@
 				void *data)
 {
 	struct module *mod = data;
-	struct gcov_info *info;
-	struct gcov_info *prev;
+	struct gcov_info *info = NULL;
+	struct gcov_info *prev = NULL;
 
 	if (event != MODULE_STATE_GOING)
 		return NOTIFY_OK;
 	mutex_lock(&gcov_lock);
-	prev = NULL;
+
 	/* Remove entries located in module from linked list. */
-	for (info = gcov_info_head; info; info = info->next) {
+	while ((info = gcov_info_next(info))) {
 		if (within(info, mod->module_core, mod->core_size)) {
-			if (prev)
-				prev->next = info->next;
-			else
-				gcov_info_head = info->next;
+			gcov_info_unlink(prev, info);
 			if (gcov_events_enabled)
 				gcov_event(GCOV_REMOVE, info);
 		} else
 			prev = info;
 	}
+
 	mutex_unlock(&gcov_lock);
 
 	return NOTIFY_OK;