[PATCH i-g-t 1/6] lib/igt_sriov_device: add helper for opening SR-IOV device sysfs

[Adam Miszczak]

On 09.10.2024 13:30, Marcin Bernatowicz wrote:
> Helper allows to open sysfs directory corresponding to SR-IOV device.
>
> Signed-off-by: Marcin Bernatowicz <marcin.bernatowicz at linux.intel.com>
> Cc: Adam Miszczak <adam.miszczak at linux.intel.com>
> Cc: Jakub Kolakowski <jakub1.kolakowski at intel.com>
> Cc: Lukasz Laguna <lukasz.laguna at intel.com>
> Cc: Michał Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Michał Winiarski <michal.winiarski at intel.com>
> Cc: Narasimha C V <narasimha.c.v at intel.com>
> Cc: Piotr Piórkowski <piotr.piorkowski at intel.com>
> Cc: Satyanarayana K V P <satyanarayana.k.v.p at intel.com>
> Cc: Tomasz Lis <tomasz.lis at intel.com>
> ---
>   lib/igt_sriov_device.c | 32 ++++++++++++++++++++++++++++++++
>   lib/igt_sriov_device.h |  1 +
>   2 files changed, 33 insertions(+)
>
> diff --git a/lib/igt_sriov_device.c b/lib/igt_sriov_device.c
> index 7c3814bf2..d20c74823 100644
> --- a/lib/igt_sriov_device.c
> +++ b/lib/igt_sriov_device.c
> @@ -5,6 +5,7 @@
>   
>   #include <dirent.h>
>   #include <errno.h>
> +#include <fcntl.h>
>   #include <limits.h>
>   #include <pciaccess.h>
>   
> @@ -381,3 +382,34 @@ void igt_sriov_unbind_vf_drm_driver(int pf, unsigned int vf_num)
>   {
>   	igt_assert(__igt_sriov_bind_vf_drm_driver(pf, vf_num, false));
>   }
> +
> +/**
> + * igt_sriov_device_sysfs_open:
> + * @pf: PF device file descriptor
> + * @vf_num: VF number (1-based to identify single VF) or 0 for PF
> + *
> + * Open the sysfs directory corresponding to SR-IOV device.
> + *
> + * Returns:
> + * The SR-IOV device sysfs directory fd, -1 on failure.
> + */
> +int igt_sriov_device_sysfs_open(int pf, unsigned int vf_num)
> +{
> +	char path[PATH_MAX];
> +	int sysfs, fd;
> +
> +	sysfs = igt_sysfs_open(pf);
> +	if (sysfs < 0)
> +		return -1;
> +
> +	if (!vf_num)
> +		snprintf(path, sizeof(path), "device");
> +	else
> +		/* vf_num is 1-based, but virtfn is 0-based */
> +		snprintf(path, sizeof(path), "device/virtfn%u", vf_num - 1);
> +
> +	fd = openat(sysfs, path, O_DIRECTORY | O_RDONLY);
> +	close(sysfs);
> +
> +	return fd;
> +}
LGTM,
Reviewed-by: Adam Miszczak <adam.miszczak at linux.intel.com>
> diff --git a/lib/igt_sriov_device.h b/lib/igt_sriov_device.h
> index 20ffc515f..dc95a4c78 100644
> --- a/lib/igt_sriov_device.h
> +++ b/lib/igt_sriov_device.h
> @@ -30,6 +30,7 @@ int igt_sriov_open_vf_drm_device(int pf, unsigned int vf_num);
>   bool igt_sriov_is_vf_drm_driver_probed(int pf, unsigned int vf_num);
>   void igt_sriov_bind_vf_drm_driver(int pf, unsigned int vf_num);
>   void igt_sriov_unbind_vf_drm_driver(int pf, unsigned int vf_num);
> +int igt_sriov_device_sysfs_open(int pf, unsigned int vf_num);
>   
>   /**
>    * for_each_sriov_vf - Helper for running code on each VF