| Message ID | 20230830030325.3786-1-laoar.shao@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 6a8faf10709161e7138202a8cf052b070971239f |
| Delegated to: | BPF |
| Headers | show |
| Series | [v2,bpf-next] bpftool: Fix build warnings with -Wtype-limits | expand |
Hello: This patch was applied to bpf/bpf.git (master) by Daniel Borkmann <daniel@iogearbox.net>: On Wed, 30 Aug 2023 03:03:25 +0000 you wrote: > Quentin reported build warnings when building bpftool : > > link.c: In function ‘perf_config_hw_cache_str’: > link.c:86:18: warning: comparison of unsigned expression in ‘>= 0’ is always true [-Wtype-limits] > 86 | if ((id) >= 0 && (id) < ARRAY_SIZE(array)) \ > | ^~ > link.c:320:20: note: in expansion of macro ‘perf_event_name’ > 320 | hw_cache = perf_event_name(evsel__hw_cache, config & 0xff); > | ^~~~~~~~~~~~~~~ > [... more of the same for the other calls to perf_event_name ...] > > [...] Here is the summary with links: - [v2,bpf-next] bpftool: Fix build warnings with -Wtype-limits https://git.kernel.org/bpf/bpf/c/6a8faf107091 You are awesome, thank you!
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index 0b214f6ab5c8..2e5c231e08ac 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -83,7 +83,7 @@ const char *evsel__hw_cache_result[PERF_COUNT_HW_CACHE_RESULT_MAX] = { #define perf_event_name(array, id) ({ \ const char *event_str = NULL; \ \ - if ((id) >= 0 && (id) < ARRAY_SIZE(array)) \ + if ((id) < ARRAY_SIZE(array)) \ event_str = array[id]; \ event_str; \ })
Quentin reported build warnings when building bpftool : link.c: In function ‘perf_config_hw_cache_str’: link.c:86:18: warning: comparison of unsigned expression in ‘>= 0’ is always true [-Wtype-limits] 86 | if ((id) >= 0 && (id) < ARRAY_SIZE(array)) \ | ^~ link.c:320:20: note: in expansion of macro ‘perf_event_name’ 320 | hw_cache = perf_event_name(evsel__hw_cache, config & 0xff); | ^~~~~~~~~~~~~~~ [... more of the same for the other calls to perf_event_name ...] He also pointed out the reason and the solution: We're always passing unsigned, so it should be safe to drop the check on (id) >= 0. Fixes: 62b57e3ddd64 ("bpftool: Add perf event names") Reported-by: Quentin Monnet <quentin@isovalent.com> Closes: https://lore.kernel.org/bpf/a35d9a2d-54a0-49ec-9ed1-8fcf1369d3cc@isovalent.com Suggested-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Acked-by: Quentin Monnet <quentin@isovalent.com> --- tools/bpf/bpftool/link.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)