Re: [PATCH v3 03/10] lib/igt_drm_netlink: Introduce DRM RAS Netlink interface library

["Koppuravuri, Ravi Kishore" <ravi.kishore.koppuravuri@intel.com>]

On 31-08-2026 14:16, Jani Nikula wrote:
> On Mon, 24 Aug 2026, Ravi Kishore Koppuravuri <ravi.kishore.koppuravuri@intel.com> wrote:
>> Introduce an IGT library for communicating with DRM RAS Generic Netlink
>> interface. Add helpers for Generic Netlink socket initialization and
>> cleanup.
>>
>> Signed-off-by: Ravi Kishore Koppuravuri <ravi.kishore.koppuravuri@intel.com>
>> ---
>>   lib/igt_drm_netlink.c | 60 +++++++++++++++++++++++++++++++++++++++++++
>>   lib/igt_drm_netlink.h | 25 ++++++++++++++++++
>>   lib/meson.build       |  1 +
>>   3 files changed, 86 insertions(+)
>>   create mode 100644 lib/igt_drm_netlink.c
>>   create mode 100644 lib/igt_drm_netlink.h
>>
>> diff --git a/lib/igt_drm_netlink.c b/lib/igt_drm_netlink.c
>> new file mode 100644
>> index 000000000..fec1639b4
>> --- /dev/null
>> +++ b/lib/igt_drm_netlink.c
>> @@ -0,0 +1,60 @@
>> +// SPDX-License-Identifier: MIT
>> +/*
>> + * Copyright © 2026 Intel Corporation
>> + */
>> +
>> +#include <stdbool.h>
>> +#include <stdint.h>
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +
>> +#include <netlink/errno.h>
>> +#include <netlink/genl/ctrl.h>
>> +#include <netlink/genl/genl.h>
>> +#include <netlink/netlink.h>
>> +
>> +#include "igt_core.h"
>> +#include "igt_drm_netlink.h"
>> +
>> +void igt_cleanup_nl_socket(struct app_context *ctx)
>> +{
>> +	if (!ctx || !ctx->sock)
>> +		return;
>> +
>> +	nl_close(ctx->sock);
>> +	nl_socket_free(ctx->sock);
>> +	ctx->sock = NULL;
>> +	ctx->family_id = -1;
>> +
>> +	igt_debug("Cleaned up netlink socket.\n");
>> +}
>> +
>> +int igt_init_nl_socket(struct app_context *ctx)
>> +{
>> +	ctx->sock = nl_socket_alloc();
>> +	if (!ctx->sock)
>> +		return -1;
>> +
>> +	igt_debug("Socket allocation successful. Connecting to Generic Netlink...\n");
>> +	if (genl_connect(ctx->sock) < 0) {
>> +		igt_cleanup_nl_socket(ctx);
>> +		return -1;
>> +	}
>> +
>> +	igt_debug("Resolving Generic Netlink family '%s'...\n", DRM_RAS_FAMILY_NAME);
>> +	ctx->family_id = genl_ctrl_resolve(ctx->sock, DRM_RAS_FAMILY_NAME);
>> +	if (ctx->family_id < 0) {
>> +		fprintf(stderr,
>> +			"Failed to resolve Generic Netlink family '%s': %s. "
>> +			"This may mean the running kernel does not expose DRM RAS support.\n",
>> +			DRM_RAS_FAMILY_NAME,
>> +			nl_geterror(ctx->family_id));
>> +		igt_cleanup_nl_socket(ctx);
>> +		return -1;
>> +	}
>> +
>> +	igt_debug("Resolved Generic Netlink family '%s' with id %d.\n",
>> +		  DRM_RAS_FAMILY_NAME, ctx->family_id);
>> +	return 0;
>> +}
>> diff --git a/lib/igt_drm_netlink.h b/lib/igt_drm_netlink.h
>> new file mode 100644
>> index 000000000..f681a3a81
>> --- /dev/null
>> +++ b/lib/igt_drm_netlink.h
>> @@ -0,0 +1,25 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Copyright © 2026 Intel Corporation
>> + */
>> +
>> +#ifndef IGT_DRM_NETLINK_H
>> +#define IGT_DRM_NETLINK_H
>> +
>> +#include <stdbool.h>
> There are no bools here?
I will update it accordingly. Thanks
>
>> +#include <stdint.h>
> There are no stdints here?
I will update it accordingly. Thanks
>
>> +
>> +#include <netlink/netlink.h>
> You could get away with a forward declaration.
I will update it accordingly. Thanks
>
>> +
>> +#include <drm-uapi/drm_ras.h>
> You're not using that here.
I will update it accordingly. Thanks
>
>> +
>> +struct app_context {
> Why doesn't the name indicate netlink in any way?z
I am using this structure to maintain the context of request received 
for the library functions and responses received from netlink functions. 
So I have not included netlink or nl for this structure name.
>
>> +	struct nl_sock *sock;
>> +	int family_id;
>> +};
>> +
>> +void igt_cleanup_nl_socket(struct app_context *ctx);
>> +int igt_init_nl_socket(struct app_context *ctx);
> IMO "nl" is the wrong place to abbreviate.
libnl is the user space library used to communicate with DRM netlink 
socket in the kernel. All libnl API references have the word "nl" for 
netlink. So, I have followed the same in my library functions as well. 
Could you pls elaborate your suggestion, if am missing anything here.
>
>> +
>> +#endif /* IGT_DRM_NETLINK_H */
>> +
>> diff --git a/lib/meson.build b/lib/meson.build
>> index 7248bbc2d..70da9a4a0 100644
>> --- a/lib/meson.build
>> +++ b/lib/meson.build
>> @@ -27,6 +27,7 @@ lib_sources = [
>>   	'igt_device_scan.c',
>>   	'igt_drm_clients.h',
>>   	'igt_drm_fdinfo.c',
>> +	'igt_drm_netlink.c',
>>           'igt_fs.c',
>>   	'igt_aux.c',
>>   	'igt_dp.c',