Re: [RFC v2 5/5] drm/xe/RAS: send multicast event on occurrence of an error

[Tomer Tayar <ttayar@habana.ai>]

On 10/11/2023 14:27, Tomer Tayar wrote:
> On 20/10/2023 18:58, Aravind Iddamsetty wrote:
>> Whenever a correctable or an uncorrectable error happens an event is sent
>> to the corresponding listeners of these groups.
>>
>> v2: Rebase
>>
>> Signed-off-by: Aravind Iddamsetty<aravind.iddamsetty@linux.intel.com>
>> ---
>>    drivers/gpu/drm/xe/xe_hw_error.c | 33 ++++++++++++++++++++++++++++++++
>>    1 file changed, 33 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_hw_error.c b/drivers/gpu/drm/xe/xe_hw_error.c
>> index bab6d4cf0b69..b0befb5e01cb 100644
>> --- a/drivers/gpu/drm/xe/xe_hw_error.c
>> +++ b/drivers/gpu/drm/xe/xe_hw_error.c
>> @@ -786,6 +786,37 @@ xe_soc_hw_error_handler(struct xe_tile *tile, const enum hardware_error hw_err)
>>    				(HARDWARE_ERROR_MAX << 1) + 1);
>>    }
>>    
>> +static void
>> +generate_netlink_event(struct xe_device *xe, const enum hardware_error hw_err)
>> +{
>> +	struct sk_buff *msg;
>> +	void *hdr;
>> +
>> +	if (!xe->drm.drm_genl_family.module)
>> +		return;
>> +
>> +	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
>> +	if (!msg) {
>> +		drm_dbg_driver(&xe->drm, "couldn't allocate memory for error multicast event\n");
>> +		return;
>> +	}
>> +
>> +	hdr = genlmsg_put(msg, 0, 0, &xe->drm.drm_genl_family, 0, DRM_RAS_CMD_ERROR_EVENT);
>> +	if (!hdr) {
>> +		drm_dbg_driver(&xe->drm, "mutlicast msg buffer is small\n");
>> +		nlmsg_free(msg);
>> +		return;
>> +	}
>> +
>> +	genlmsg_end(msg, hdr);
>> +
>> +	genlmsg_multicast(&xe->drm.drm_genl_family, msg, 0,
>> +			  hw_err ?
>> +			  DRM_GENL_MCAST_UNCORR_ERR
>> +			  : DRM_GENL_MCAST_CORR_ERR,
>> +			  GFP_ATOMIC);
> I agree that hiding/wrapping any netlink/genetlink API/macro with a DRM
> helper would be sometimes redundant,
> and that in some cases the specific DRM driver would have to "dirt its
> hands" and deal with netlink (e.g. fill_error_details() in patch #3).
> However maybe here a DRM helper would have been useful, so we won't see
> a copy of this sequence in other DRM drivers?
>
> Thanks,
> Tomer

After rethinking, it is possible that different DRM drivers will need 
some flexibility when it comes to calling genlmsg_put(), as they might 
want to have more of this call in order to attach some data related to 
the error indication.
In that case, adding a DRM function that wraps it may me redundant.
What do you think?

>> +}
>> +
>>    static void
>>    xe_hw_error_source_handler(struct xe_tile *tile, const enum hardware_error hw_err)
>>    {
>> @@ -849,6 +880,8 @@ xe_hw_error_source_handler(struct xe_tile *tile, const enum hardware_error hw_er
>>    	}
>>    
>>    	xe_mmio_write32(gt, DEV_ERR_STAT_REG(hw_err), errsrc);
>> +
>> +	generate_netlink_event(tile_to_xe(tile), hw_err);
>>    unlock:
>>    	spin_unlock_irqrestore(&tile_to_xe(tile)->irq.lock, flags);
>>    }
>