perf symbols: Simplify symbol machinery setup

And also express its configuration toggles via a struct.

Now all one has to do is to call symbol__init(NULL) if the
defaults are OK, or pass a struct symbol_conf pointer with the
desired configuration.

If a tool uses kernel_maps__find_symbol() to look at the kernel
and modules mappings for a symbol but didn't call symbol__init()
first, that will generate a one time warning too, alerting the
subcommand developer that symbol__init() must be called.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1259071517-3242-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 21 insertions, 10 deletions

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 44d81d5ae8cf..c4ca974b36e3 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -6,6 +6,7 @@
 
 #include "debug.h"
 
+#include <asm/bug.h>
 #include <libelf.h>
 #include <gelf.h>
 #include <elf.h>
@@ -37,6 +38,11 @@ unsigned int symbol__priv_size;
 static int vmlinux_path__nr_entries;
 static char **vmlinux_path;
 
+static struct symbol_conf symbol_conf__defaults = {
+        .use_modules      = true,
+        .try_vmlinux_path = true,
+};
+
 static struct rb_root kernel_maps;
 
 static void dso__fixup_sym_end(struct dso *self)
@@ -1166,7 +1172,9 @@ struct symbol *kernel_maps__find_symbol(u64 ip, struct map **mapp,
         if (map) {
                 ip = map->map_ip(map, ip);
                 return map__find_symbol(map, ip, filter);
-        }
+        } else
+                WARN_ONCE(RB_EMPTY_ROOT(&kernel_maps),
+                          "Empty kernel_maps, was symbol__init() called?\n");
 
         return NULL;
 }
@@ -1485,9 +1493,9 @@ size_t dsos__fprintf_buildid(FILE *fp)
         return ret;
 }
 
-static int kernel_maps__create_kernel_map(const char *vmlinux_name)
+static int kernel_maps__create_kernel_map(const struct symbol_conf *conf)
 {
-        struct dso *kernel = dso__new(vmlinux_name ?: "[kernel.kallsyms]");
+        struct dso *kernel = dso__new(conf->vmlinux_name ?: "[kernel.kallsyms]");
 
         if (kernel == NULL)
                 return -1;
@@ -1577,18 +1585,21 @@ out_fail:
         return -1;
 }
 
-int kernel_maps__init(const char *vmlinux_name, bool try_vmlinux_path,
-                      bool use_modules)
+static int kernel_maps__init(const struct symbol_conf *conf)
 {
-        if (try_vmlinux_path && vmlinux_path__init() < 0)
+        const struct symbol_conf *pconf = conf ?: &symbol_conf__defaults;
+
+        symbol__priv_size = pconf->priv_size;
+
+        if (pconf->try_vmlinux_path && vmlinux_path__init() < 0)
                 return -1;
 
-        if (kernel_maps__create_kernel_map(vmlinux_name) < 0) {
+        if (kernel_maps__create_kernel_map(pconf) < 0) {
                 vmlinux_path__exit();
                 return -1;
         }
 
-        if (use_modules && kernel_maps__create_module_maps() < 0)
+        if (pconf->use_modules && kernel_maps__create_module_maps() < 0)
                 pr_debug("Failed to load list of modules in use, "
                          "continuing...\n");
         /*
@@ -1598,8 +1609,8 @@ int kernel_maps__init(const char *vmlinux_name, bool try_vmlinux_path,
         return 0;
 }
 
-void symbol__init(unsigned int priv_size)
+int symbol__init(struct symbol_conf *conf)
 {
         elf_version(EV_CURRENT);
-        symbol__priv_size = priv_size;
+        return kernel_maps__init(conf);
 }