[PATCH] cxl: Add support for ASB_Notify on POWER9

[christophe lombard]

Le 23/11/2017 à 15:16, Vaibhav Jain a écrit :
> Hi Christophe,
> 
> Few review comments:
> 
> Christophe Lombard <clombard at linux.vnet.ibm.com> writes:
>> +
>> +int cxl_context_thread_tidr(struct cxl_context *ctx, int assign)
>> +{
>> +	int rc = 0;
>> +
>> +	/* Clear any TIDR value assigned to the current thread */
>> +	if (!assign) {
>> +		clear_thread_tidr(current);
>> +		ctx->tid = 0;
>> +	} else {
>> +		/* Assign a unique TIDR (thread id) for the current thread */
>> +		rc = set_thread_tidr(current);
>> +		if (!rc)
>> +			ctx->tid = current->thread.tidr;
> set_thread_tidr can also return non-zero error values and will never
> return '0'. So this condition should be 'if(rc > 0)' instead of 'if (!rc)'

good point. Thanks for this.

> 
>> +#define CXL_IOCTL_GET_AFU_ID		_IOR(CXL_MAGIC, 0x02, struct cxl_afu_id)
>> +#define CXL_IOCTL_THREAD_TIDR		_IOR(CXL_MAGIC, 0x03,
>> int)
> Instead of adding a new syscall I think assiging a thread-id can be
> better done by adding a new flag to the cxl_ioctl_start_work.flag
> field and using one of the reserved fields to return the allocated tid
> back to the user.
> 

We have worked previously on this solution but this solution is too 
restrictive for now - we offer the possibility to configure and to clear
the tidr from user land - and for the future implementation.