Re: [PATCH 1/2] IB/core: Add support for enhanced atomic operations

[Vladimir Sokolovsky <vlad-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>]

Sean Hefty wrote:
>> enum ib_atomic_cap {
>> @@ -472,7 +473,9 @@ enum ib_wc_opcode {
>>  * receive by testing (opcode & IB_WC_RECV).
>>  */
>> 	IB_WC_RECV			= 1 << 7,
>> -	IB_WC_RECV_RDMA_WITH_IMM
>> +	IB_WC_RECV_RDMA_WITH_IMM,
>> +	IB_WC_MASKED_COMP_SWAP,
>> +	IB_WC_MASKED_FETCH_ADD
>> };
> 
> This breaks the ability to check for a receive by testing opcode & IB_WC_RECV.

Thanks Sean,
I'll send an updated patch with the fix.

> Is it even necessary to define new work completion opcodes?
> 
>> enum ib_wc_flags {
>> @@ -689,6 +692,8 @@ enum ib_wr_opcode {
>> 	IB_WR_RDMA_READ_WITH_INV,
>> 	IB_WR_LOCAL_INV,
>> 	IB_WR_FAST_REG_MR,
>> +	IB_WR_ATOMIC_MASKED_CMP_AND_SWP,
>> +	IB_WR_ATOMIC_MASKED_FETCH_AND_ADD,
>> };
> 
> Just tossing this out as a possibility -- the mask itself could be used to
> indicate the type of operation.  Kernel clients would always set the mask for
> all atomic operations.

I don't have a strong opinion on this, but it looks to me more natural to use
new opcodes and this way it is backward compatible.

Regards,
Vladimir
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