Re: [PATCH bpf 1/4] selftests: bpf: use a temporary file in test_sockmap

[Martin Lau]

On Thu, Jan 23, 2020 at 04:59:30PM +0000, Lorenz Bauer wrote:
> Use a proper temporary file for sendpage tests. This means that running
> the tests doesn't clutter the working directory, and allows running the
> test on read-only filesystems.
> 
> Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> ---
>  tools/testing/selftests/bpf/test_sockmap.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/test_sockmap.c b/tools/testing/selftests/bpf/test_sockmap.c
> index 4a851513c842..779e11da979c 100644
> --- a/tools/testing/selftests/bpf/test_sockmap.c
> +++ b/tools/testing/selftests/bpf/test_sockmap.c
> @@ -331,7 +331,7 @@ static int msg_loop_sendpage(int fd, int iov_length, int cnt,
>  	FILE *file;
>  	int i, fp;
>  
> -	file = fopen(".sendpage_tst.tmp", "w+");
> +	file = tmpfile();
>  	if (!file) {
>  		perror("create file for sendpage");
>  		return 1;
> @@ -340,13 +340,8 @@ static int msg_loop_sendpage(int fd, int iov_length, int cnt,
>  		fwrite(&k, sizeof(char), 1, file);
>  	fflush(file);
>  	fseek(file, 0, SEEK_SET);
> -	fclose(file);
>  
> -	fp = open(".sendpage_tst.tmp", O_RDONLY);
> -	if (fp < 0) {
> -		perror("reopen file for sendpage");
> -		return 1;
> -	}
> +	fp = fileno(file);
It may be better to keep fp == -1 check here.
It is not clear to me the original intention of reopen.
I would defer to John for comment.

>  
>  	clock_gettime(CLOCK_MONOTONIC, &s->start);
>  	for (i = 0; i < cnt; i++) {