Re: [PATCH bpf 3/4] selftests/bpf: Provide a generic [un]load_module helper

[Jiri Olsa <olsajiri@gmail.com>]

On Tue, Oct 08, 2024 at 12:35:18PM +0200, Toke Høiland-Jørgensen wrote:
> From: Simon Sundberg <simon.sundberg@kau.se>
> 
> Generalize the previous [un]load_bpf_testmod() helpers (in
> testing_helpers.c) to the more generic [un]load_module(), which can
> load an arbitrary kernel module by name. This allows future selftests
> to more easily load custom kernel modules other than bpf_testmod.ko.
> Refactor [un]load_bpf_testmod() to wrap this new helper.
> 
> Signed-off-by: Simon Sundberg <simon.sundberg@kau.se>
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>

Acked-by: Jiri Olsa <jolsa@kernel.org>

jirka

> ---
>  tools/testing/selftests/bpf/testing_helpers.c | 34 +++++++++++++++++----------
>  tools/testing/selftests/bpf/testing_helpers.h |  2 ++
>  2 files changed, 24 insertions(+), 12 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
> index d3c3c3a24150f99abd13ecb7d7b11d8f7351560d..5e9f16683be5460b1a295fb9754df761cbd090ea 100644
> --- a/tools/testing/selftests/bpf/testing_helpers.c
> +++ b/tools/testing/selftests/bpf/testing_helpers.c
> @@ -367,7 +367,7 @@ int delete_module(const char *name, int flags)
>  	return syscall(__NR_delete_module, name, flags);
>  }
>  
> -int unload_bpf_testmod(bool verbose)
> +int unload_module(const char *name, bool verbose)
>  {
>  	int ret, cnt = 0;
>  
> @@ -375,11 +375,11 @@ int unload_bpf_testmod(bool verbose)
>  		fprintf(stdout, "Failed to trigger kernel-side RCU sync!\n");
>  
>  	for (;;) {
> -		ret = delete_module("bpf_testmod", 0);
> +		ret = delete_module(name, 0);
>  		if (!ret || errno != EAGAIN)
>  			break;
>  		if (++cnt > 10000) {
> -			fprintf(stdout, "Unload of bpf_testmod timed out\n");
> +			fprintf(stdout, "Unload of %s timed out\n", name);
>  			break;
>  		}
>  		usleep(100);
> @@ -388,41 +388,51 @@ int unload_bpf_testmod(bool verbose)
>  	if (ret) {
>  		if (errno == ENOENT) {
>  			if (verbose)
> -				fprintf(stdout, "bpf_testmod.ko is already unloaded.\n");
> +				fprintf(stdout, "%s.ko is already unloaded.\n", name);
>  			return -1;
>  		}
> -		fprintf(stdout, "Failed to unload bpf_testmod.ko from kernel: %d\n", -errno);
> +		fprintf(stdout, "Failed to unload %s.ko from kernel: %d\n", name, -errno);
>  		return -1;
>  	}
>  	if (verbose)
> -		fprintf(stdout, "Successfully unloaded bpf_testmod.ko.\n");
> +		fprintf(stdout, "Successfully unloaded %s.ko.\n", name);
>  	return 0;
>  }
>  
> -int load_bpf_testmod(bool verbose)
> +int load_module(const char *path, bool verbose)
>  {
>  	int fd;
>  
>  	if (verbose)
> -		fprintf(stdout, "Loading bpf_testmod.ko...\n");
> +		fprintf(stdout, "Loading %s...\n", path);
>  
> -	fd = open("bpf_testmod.ko", O_RDONLY);
> +	fd = open(path, O_RDONLY);
>  	if (fd < 0) {
> -		fprintf(stdout, "Can't find bpf_testmod.ko kernel module: %d\n", -errno);
> +		fprintf(stdout, "Can't find %s kernel module: %d\n", path, -errno);
>  		return -ENOENT;
>  	}
>  	if (finit_module(fd, "", 0)) {
> -		fprintf(stdout, "Failed to load bpf_testmod.ko into the kernel: %d\n", -errno);
> +		fprintf(stdout, "Failed to load %s into the kernel: %d\n", path, -errno);
>  		close(fd);
>  		return -EINVAL;
>  	}
>  	close(fd);
>  
>  	if (verbose)
> -		fprintf(stdout, "Successfully loaded bpf_testmod.ko.\n");
> +		fprintf(stdout, "Successfully loaded %s.\n", path);
>  	return 0;
>  }
>  
> +int unload_bpf_testmod(bool verbose)
> +{
> +	return unload_module("bpf_testmod", verbose);
> +}
> +
> +int load_bpf_testmod(bool verbose)
> +{
> +	return load_module("bpf_testmod.ko", verbose);
> +}
> +
>  /*
>   * Trigger synchronize_rcu() in kernel.
>   */
> diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
> index d55f6ab124338ccab33bc120ca7e3baa18264aea..46d7f7089f636b0d2476859fd0fa5e1c4b305419 100644
> --- a/tools/testing/selftests/bpf/testing_helpers.h
> +++ b/tools/testing/selftests/bpf/testing_helpers.h
> @@ -38,6 +38,8 @@ int unload_bpf_testmod(bool verbose);
>  int kern_sync_rcu(void);
>  int finit_module(int fd, const char *param_values, int flags);
>  int delete_module(const char *name, int flags);
> +int load_module(const char *path, bool verbose);
> +int unload_module(const char *name, bool verbose);
>  
>  static inline __u64 get_time_ns(void)
>  {
> 
> -- 
> 2.47.0
>