diff mbox series

[bpf-next,5/7] selftests/bpf: Remove the "/sys" mount and umount dance in {open,close}_netns

Message ID 20221129070900.3142427-6-martin.lau@linux.dev (mailing list archive)
State Accepted
Commit 3084097c369c57c9bbd81e5bf47b36b6b27390fc
Delegated to: BPF
Headers show
Series selftests/bpf: Remove unnecessary mount/umount dance | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 10 maintainers not CCed: sdf@google.com shuah@kernel.org kpsingh@kernel.org linux-kselftest@vger.kernel.org john.fastabend@gmail.com haoluo@google.com jolsa@kernel.org song@kernel.org mykolal@fb.com yhs@fb.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 68 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
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Commit Message

Martin KaFai Lau Nov. 29, 2022, 7:08 a.m. UTC 
From: Martin KaFai Lau <martin.lau@kernel.org>

The previous patches have removed the need to do the mount and umount
dance when switching netns. In particular:
* Avoid remounting /sys/fs/bpf to have a clean start
* Avoid remounting /sys to get a ifindex of a particular netns

This patch can finally remove the mount and umount dance in
{open,close}_netns which is unnecessarily complicated and
error-prone.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
 tools/testing/selftests/bpf/network_helpers.c | 51 ++-----------------
 1 file changed, 5 insertions(+), 46 deletions(-)
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 1f37adff7632..01de33191226 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -390,49 +390,6 @@  struct nstoken {
 	int orig_netns_fd;
 };
 
-static int setns_by_fd(int nsfd)
-{
-	int err;
-
-	err = setns(nsfd, CLONE_NEWNET);
-	close(nsfd);
-
-	if (!ASSERT_OK(err, "setns"))
-		return err;
-
-	/* Switch /sys to the new namespace so that e.g. /sys/class/net
-	 * reflects the devices in the new namespace.
-	 */
-	err = unshare(CLONE_NEWNS);
-	if (!ASSERT_OK(err, "unshare"))
-		return err;
-
-	/* Make our /sys mount private, so the following umount won't
-	 * trigger the global umount in case it's shared.
-	 */
-	err = mount("none", "/sys", NULL, MS_PRIVATE, NULL);
-	if (!ASSERT_OK(err, "remount private /sys"))
-		return err;
-
-	err = umount2("/sys", MNT_DETACH);
-	if (!ASSERT_OK(err, "umount2 /sys"))
-		return err;
-
-	err = mount("sysfs", "/sys", "sysfs", 0, NULL);
-	if (!ASSERT_OK(err, "mount /sys"))
-		return err;
-
-	err = mount("bpffs", "/sys/fs/bpf", "bpf", 0, NULL);
-	if (!ASSERT_OK(err, "mount /sys/fs/bpf"))
-		return err;
-
-	err = mount("debugfs", "/sys/kernel/debug", "debugfs", 0, NULL);
-	if (!ASSERT_OK(err, "mount /sys/kernel/debug"))
-		return err;
-
-	return 0;
-}
-
 struct nstoken *open_netns(const char *name)
 {
 	int nsfd;
@@ -453,8 +410,9 @@  struct nstoken *open_netns(const char *name)
 	if (!ASSERT_GE(nsfd, 0, "open netns fd"))
 		goto fail;
 
-	err = setns_by_fd(nsfd);
-	if (!ASSERT_OK(err, "setns_by_fd"))
+	err = setns(nsfd, CLONE_NEWNET);
+	close(nsfd);
+	if (!ASSERT_OK(err, "setns"))
 		goto fail;
 
 	return token;
@@ -465,6 +423,7 @@  struct nstoken *open_netns(const char *name)
 
 void close_netns(struct nstoken *token)
 {
-	ASSERT_OK(setns_by_fd(token->orig_netns_fd), "setns_by_fd");
+	ASSERT_OK(setns(token->orig_netns_fd, CLONE_NEWNET), "setns");
+	close(token->orig_netns_fd);
 	free(token);
 }