2020-04-29 13:24:40

by Arnd Bergmann

Subject: [PATCH] bpf: fix unused variable warning

Hiding the only using of bpf_link_type_strs[] in an #ifdef causes
an unused-variable warning:

kernel/bpf/syscall.c:2280:20: error: 'bpf_link_type_strs' defined but not used [-Werror=unused-variable]
2280 | static const char *bpf_link_type_strs[] = {

Move the definition into the same #ifdef.

Fixes: f2e10bff16a0 ("bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link")
Signed-off-by: Arnd Bergmann <[email protected]>
---
kernel/bpf/syscall.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 3cea7602de78..5e86d8749e6e 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2274,6 +2274,7 @@ static int bpf_link_release(struct inode *inode, struct file *filp)
return 0;
}

+#ifdef CONFIG_PROC_FS
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
#define BPF_MAP_TYPE(_id, _ops)
#define BPF_LINK_TYPE(_id, _name) [_id] = #_name,
@@ -2285,7 +2286,6 @@ static const char *bpf_link_type_strs[] = {
#undef BPF_MAP_TYPE
#undef BPF_LINK_TYPE

-#ifdef CONFIG_PROC_FS
static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp)
{
const struct bpf_link *link = filp->private_data;
--
2.26.0

2020-04-29 20:38:47

by Andrii Nakryiko

Subject: Re: [PATCH] bpf: fix unused variable warning

On Wed, Apr 29, 2020 at 6:23 AM Arnd Bergmann <[email protected]> wrote:
>
> Hiding the only using of bpf_link_type_strs[] in an #ifdef causes
> an unused-variable warning:
>
> kernel/bpf/syscall.c:2280:20: error: 'bpf_link_type_strs' defined but not used [-Werror=unused-variable]
> 2280 | static const char *bpf_link_type_strs[] = {
>
> Move the definition into the same #ifdef.
>
> Fixes: f2e10bff16a0 ("bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---

Thanks for the fix, LGTM.

Acked-by: Andrii Nakryiko <[email protected]>

> kernel/bpf/syscall.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 3cea7602de78..5e86d8749e6e 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -2274,6 +2274,7 @@ static int bpf_link_release(struct inode *inode, struct file *filp)
> return 0;
> }
>
> +#ifdef CONFIG_PROC_FS
> #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
> #define BPF_MAP_TYPE(_id, _ops)
> #define BPF_LINK_TYPE(_id, _name) [_id] = #_name,
> @@ -2285,7 +2286,6 @@ static const char *bpf_link_type_strs[] = {
> #undef BPF_MAP_TYPE
> #undef BPF_LINK_TYPE
>
> -#ifdef CONFIG_PROC_FS
> static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp)
> {
> const struct bpf_link *link = filp->private_data;
> --
> 2.26.0
>

2020-04-29 23:18:27

by Daniel Borkmann

Subject: Re: [PATCH] bpf: fix unused variable warning

On 4/29/20 3:21 PM, Arnd Bergmann wrote:
> Hiding the only using of bpf_link_type_strs[] in an #ifdef causes
> an unused-variable warning:
>
> kernel/bpf/syscall.c:2280:20: error: 'bpf_link_type_strs' defined but not used [-Werror=unused-variable]
> 2280 | static const char *bpf_link_type_strs[] = {
>
> Move the definition into the same #ifdef.
>
> Fixes: f2e10bff16a0 ("bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link")
> Signed-off-by: Arnd Bergmann <[email protected]>

Applied, thanks!