[PATCH v1 10/11] perf tools: Only enter mount namespace if necessary

[Namhyung Kim]

Add dso_binary_type__needs_ns() to distinguish DSO binary types that
reside inside the target process's mount namespace and chroot from
host-side paths.

Gate mount namespace entry in dso__data_file_size() and do_open() using
dso_binary_type__needs_ns().  And remove redundant outer mountns entry
in around dso__data_get_fd().

Assisted-by: LLM
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
 tools/perf/util/capstone.c |  6 ++++--
 tools/perf/util/dso.c      | 12 ++++++++----
 tools/perf/util/dso.h      | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/capstone.c b/tools/perf/util/capstone.c
index 95881f15324aa614..9a8646ff026d92a4 100644
--- a/tools/perf/util/capstone.c
+++ b/tools/perf/util/capstone.c
@@ -653,9 +653,11 @@ int symbol__disassemble_capstone_powerpc(const char *filename __maybe_unused,
 	if (args->options->objdump_path)
 		return -1;
 
-	nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
+	if (dso_binary_type__needs_ns(dso__binary_type(dso)))
+		nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
 	fd = open(filename, O_RDONLY);
-	nsinfo__mountns_exit(&nsc);
+	if (dso_binary_type__needs_ns(dso__binary_type(dso)))
+		nsinfo__mountns_exit(&nsc);
 	if (fd < 0)
 		return -1;
 
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 4331b48505b2b10e..50dd215f81f6737c 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -682,14 +682,15 @@ static int open_dso(struct dso *dso, struct machine *machine)
 {
 	int fd;
 	struct nscookie nsc;
+	bool nsenter = dso_binary_type__needs_ns(dso__binary_type(dso));
 
-	if (dso__binary_type(dso) != DSO_BINARY_TYPE__BUILD_ID_CACHE) {
+	if (nsenter) {
 		mutex_lock(dso__lock(dso));
 		nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
 		mutex_unlock(dso__lock(dso));
 	}
 	fd = __open_dso(dso, machine);
-	if (dso__binary_type(dso) != DSO_BINARY_TYPE__BUILD_ID_CACHE)
+	if (nsenter)
 		nsinfo__mountns_exit(&nsc);
 
 	if (fd >= 0) {
@@ -2081,11 +2082,14 @@ static const u8 *__dso__read_symbol(struct dso *dso, const char *symfs_filename,
 	};
 	u8 *code_buf = NULL;
 	int saved_errno;
+	bool nsenter = dso_binary_type__needs_ns(dso__binary_type(dso));
 
-	nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
+	if (nsenter)
+		nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
 	fd = open(symfs_filename, O_RDONLY | O_CLOEXEC);
 	saved_errno = errno;
-	nsinfo__mountns_exit(&nsc);
+	if (nsenter)
+		nsinfo__mountns_exit(&nsc);
 	if (fd < 0) {
 		errno = saved_errno;
 		return NULL;
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index e53c83c23c578918..c4ff19f575b88a9e 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -141,6 +141,40 @@ enum dso_binary_type {
 	DSO_BINARY_TYPE__NOT_FOUND,
 };
 
+static inline bool dso_binary_type__needs_ns(enum dso_binary_type type)
+{
+	switch (type) {
+	case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
+	case DSO_BINARY_TYPE__DEBUGLINK:
+	case DSO_BINARY_TYPE__GNU_DEBUGDATA:
+		return true;
+	case DSO_BINARY_TYPE__KALLSYMS:
+	case DSO_BINARY_TYPE__GUEST_KALLSYMS:
+	case DSO_BINARY_TYPE__VMLINUX:
+	case DSO_BINARY_TYPE__GUEST_VMLINUX:
+	case DSO_BINARY_TYPE__JAVA_JIT:
+	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
+	case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
+	case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
+	case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
+	case DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO:
+	case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
+	case DSO_BINARY_TYPE__GUEST_KMODULE:
+	case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
+	case DSO_BINARY_TYPE__KCORE:
+	case DSO_BINARY_TYPE__GUEST_KCORE:
+	case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
+	case DSO_BINARY_TYPE__BPF_PROG_INFO:
+	case DSO_BINARY_TYPE__BPF_IMAGE:
+	case DSO_BINARY_TYPE__OOL:
+	case DSO_BINARY_TYPE__NOT_FOUND:
+	default:
+		return false;
+	}
+}
+
 enum dso_space_type {
 	DSO_SPACE__USER = 0,
 	DSO_SPACE__KERNEL,
-- 
2.56.0.257.gf7497c7d27-goog