diff mbox series

[bpf-next] selftests/bpf: Fix return value checks in perf_event_stackmap.c

Message ID 20220407153814.104914-1-ytcoode@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series [bpf-next] selftests/bpf: Fix return value checks in perf_event_stackmap.c | 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 Single patches do not need cover letters
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 success CCed 14 of 14 maintainers
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/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, 12 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next-VM_Test-2 success Logs for Kernel LATEST on z15 + selftests
bpf/vmtest-bpf-next-VM_Test-1 success Logs for Kernel LATEST on ubuntu-latest + selftests

Commit Message

Yuntao Wang April 7, 2022, 3:38 p.m. UTC
The bpf_get_stackid() function may also return 0 on success.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
---
 tools/testing/selftests/bpf/progs/perf_event_stackmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Shuah Khan April 7, 2022, 7:23 p.m. UTC | #1
On 4/7/22 9:38 AM, Yuntao Wang wrote:
> The bpf_get_stackid() function may also return 0 on success.

Can you add couple of sentences to describe what this patch
does? bpf_get_stackid() may also return doesn't really say
anything about why this patch is needed.

> 
> Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
> ---
>   tools/testing/selftests/bpf/progs/perf_event_stackmap.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/progs/perf_event_stackmap.c b/tools/testing/selftests/bpf/progs/perf_event_stackmap.c
> index b3fcb5274ee0..f793280a3238 100644
> --- a/tools/testing/selftests/bpf/progs/perf_event_stackmap.c
> +++ b/tools/testing/selftests/bpf/progs/perf_event_stackmap.c
> @@ -35,10 +35,10 @@ int oncpu(void *ctx)
>   	long val;
>   
>   	val = bpf_get_stackid(ctx, &stackmap, 0);
> -	if (val > 0)
> +	if (val >= 0)
>   		stackid_kernel = 2;
>   	val = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
> -	if (val > 0)
> +	if (val >= 0)
>   		stackid_user = 2;
>   
>   	trace = bpf_map_lookup_elem(&stackdata_map, &key);
> 
Linux 5.18-rc1 shows a couple of more bpf_get_stackid() in this function.
Removed in bpf-next - I assume.

The change is good. I would like to see it explained better in the
commit log.

With the commit log fixed to explain why this change is needed and
what happens if val equals to 0 condition isn't checked:

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/progs/perf_event_stackmap.c b/tools/testing/selftests/bpf/progs/perf_event_stackmap.c
index b3fcb5274ee0..f793280a3238 100644
--- a/tools/testing/selftests/bpf/progs/perf_event_stackmap.c
+++ b/tools/testing/selftests/bpf/progs/perf_event_stackmap.c
@@ -35,10 +35,10 @@  int oncpu(void *ctx)
 	long val;
 
 	val = bpf_get_stackid(ctx, &stackmap, 0);
-	if (val > 0)
+	if (val >= 0)
 		stackid_kernel = 2;
 	val = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
-	if (val > 0)
+	if (val >= 0)
 		stackid_user = 2;
 
 	trace = bpf_map_lookup_elem(&stackdata_map, &key);