perf symbols: Encapsulate dsos list head into struct dsos

This is a precursor patch to enable long name searching of DSOs using
a rbtree.

In this patch, a new dsos structure is created which contains only a
list head structure for the moment.

The new dsos structure is used, in turn, in the machine structure for
the user_dsos and kernel_dsos fields.

Only the following 3 dsos functions are modified to accept the new dsos
structure parameter instead of list_head:

 - dsos__add()
 - dsos__find()
 - __dsos__findnew()

Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Douglas Hatch <doug.hatch@hp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Link: http://lkml.kernel.org/r/1412021249-19201-2-git-send-email-Waiman.Long@hp.com
[ Move struct dsos to dso.h to reduce the dso methods depends on machine.h ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 158c787..ce0de00 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -214,11 +214,11 @@
 {
 	int err;
 
-	err = __dsos__hit_all(&machine->kernel_dsos);
+	err = __dsos__hit_all(&machine->kernel_dsos.head);
 	if (err)
 		return err;
 
-	return __dsos__hit_all(&machine->user_dsos);
+	return __dsos__hit_all(&machine->user_dsos.head);
 }
 
 int dsos__hit_all(struct perf_session *session)
@@ -288,11 +288,12 @@
 		umisc = PERF_RECORD_MISC_GUEST_USER;
 	}
 
-	err = __dsos__write_buildid_table(&machine->kernel_dsos, machine,
+	err = __dsos__write_buildid_table(&machine->kernel_dsos.head, machine,
 					  machine->pid, kmisc, fd);
 	if (err == 0)
-		err = __dsos__write_buildid_table(&machine->user_dsos, machine,
-						  machine->pid, umisc, fd);
+		err = __dsos__write_buildid_table(&machine->user_dsos.head,
+						  machine, machine->pid, umisc,
+						  fd);
 	return err;
 }
 
@@ -455,9 +456,10 @@
 
 static int machine__cache_build_ids(struct machine *machine, const char *debugdir)
 {
-	int ret = __dsos__cache_build_ids(&machine->kernel_dsos, machine,
+	int ret = __dsos__cache_build_ids(&machine->kernel_dsos.head, machine,
 					  debugdir);
-	ret |= __dsos__cache_build_ids(&machine->user_dsos, machine, debugdir);
+	ret |= __dsos__cache_build_ids(&machine->user_dsos.head, machine,
+				       debugdir);
 	return ret;
 }
 
@@ -483,8 +485,10 @@
 
 static bool machine__read_build_ids(struct machine *machine, bool with_hits)
 {
-	bool ret = __dsos__read_build_ids(&machine->kernel_dsos, with_hits);
-	ret |= __dsos__read_build_ids(&machine->user_dsos, with_hits);
+	bool ret;
+
+	ret  = __dsos__read_build_ids(&machine->kernel_dsos.head, with_hits);
+	ret |= __dsos__read_build_ids(&machine->user_dsos.head, with_hits);
 	return ret;
 }
 
@@ -1548,7 +1552,7 @@
 				    struct perf_session *session)
 {
 	int err = -1;
-	struct list_head *head;
+	struct dsos *dsos;
 	struct machine *machine;
 	u16 misc;
 	struct dso *dso;
@@ -1563,22 +1567,22 @@
 	switch (misc) {
 	case PERF_RECORD_MISC_KERNEL:
 		dso_type = DSO_TYPE_KERNEL;
-		head = &machine->kernel_dsos;
+		dsos = &machine->kernel_dsos;
 		break;
 	case PERF_RECORD_MISC_GUEST_KERNEL:
 		dso_type = DSO_TYPE_GUEST_KERNEL;
-		head = &machine->kernel_dsos;
+		dsos = &machine->kernel_dsos;
 		break;
 	case PERF_RECORD_MISC_USER:
 	case PERF_RECORD_MISC_GUEST_USER:
 		dso_type = DSO_TYPE_USER;
-		head = &machine->user_dsos;
+		dsos = &machine->user_dsos;
 		break;
 	default:
 		goto out;
 	}
 
-	dso = __dsos__findnew(head, filename);
+	dso = __dsos__findnew(dsos, filename);
 	if (dso != NULL) {
 		char sbuild_id[BUILD_ID_SIZE * 2 + 1];