Re: [PATCH RFC net-next v1 2/5] selftests: ncdevmem: Implement devmem TCP TX

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

Mina Almasry wrote:
> Add support for devmem TX in ncdevmem.
> 
> This is a combination of the ncdevmem from the devmem TCP series RFCv1
> which included the TX path, and work by Stan to include the netlink API
> and refactored on top of his generic memory_provider support.
> 
> Signed-off-by: Mina Almasry <almasrymina@google.com>
> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
> ---
>  .../selftests/drivers/net/hw/ncdevmem.c       | 261 +++++++++++++++++-
>  1 file changed, 259 insertions(+), 2 deletions(-)
> 

> +static unsigned long gettimeofday_ms(void)
> +{
> +	struct timeval tv;
> +
> +	gettimeofday(&tv, NULL);
> +	return (tv.tv_sec * 1000) + (tv.tv_usec / 1000);
> +}

Consider uint64_t and 1000ULL to avoid overflow on 32-bit platforms in
2034 (currently at 1.7^10^9 usec since start of epoch).

Or use clock_gettime CLOCK_MONOTONIC.

> +
> +static int do_poll(int fd)
> +{
> +	struct pollfd pfd;
> +	int ret;
> +
> +	pfd.events = POLLERR;
> +	pfd.revents = 0;

Not important but since demonstrator code:
no need to set POLLERR on events. Errors cannot be masked.

> +	pfd.fd = fd;
> +
> +	ret = poll(&pfd, 1, waittime_ms);
> +	if (ret == -1)
> +		error(1, errno, "poll");
> +
> +	return ret && (pfd.revents & POLLERR);
> +}