perf symbols: kallsyms__delta() needs the kmap, not the map

It was only using the map to obtain its kmap, so do the validation in
its called, __dso__load_kallsyms() and pass the kmap, that will be used
in the following patches in similar simplifications.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-u6p9hbonlqzpl6o1z9xzxd75@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/symbol.c

@@ -1267,14 +1267,10 @@ out_err:
  * If the kernel is relocated at boot time, kallsyms won't match.  Compute the
  * delta based on the relocation reference symbol.
  */
-static int kallsyms__delta(struct map *map, const char *filename, u64 *delta)
+static int kallsyms__delta(struct kmap *kmap, const char *filename, u64 *delta)
 {
-	struct kmap *kmap = map__kmap(map);
 	u64 addr;
 
-	if (!kmap)
-		return -1;
-
 	if (!kmap->ref_reloc_sym || !kmap->ref_reloc_sym->name)
 		return 0;
 
@@ -1288,15 +1284,19 @@ static int kallsyms__delta(struct map *map, const char *filename, u64 *delta)
 int __dso__load_kallsyms(struct dso *dso, const char *filename,
 			 struct map *map, bool no_kcore)
 {
+	struct kmap *kmap = map__kmap(map);
 	u64 delta = 0;
 
 	if (symbol__restricted_filename(filename, "/proc/kallsyms"))
 		return -1;
 
+	if (!kmap || !kmap->kmaps)
+		return -1;
+
 	if (dso__load_all_kallsyms(dso, filename) < 0)
 		return -1;
 
-	if (kallsyms__delta(map, filename, &delta))
+	if (kallsyms__delta(kmap, filename, &delta))
 		return -1;
 
 	symbols__fixup_end(&dso->symbols);