Re: [PATCH for-next v3 1/3] RDMA/rxe: Add a type flag to rxe_queue structs

["Pearson, Robert B" <rpearsonhpe@gmail.com>]

On 5/28/2021 3:31 AM, Zhu Yanjun wrote:
> On Fri, May 28, 2021 at 3:47 AM Bob Pearson <rpearsonhpe@gmail.com> wrote:
>> To create optimal code only want to use smp_load_acquire() and
>> smp_store_release() for user indices in rxe_queue APIs since
>> kernel indices are protected by locks which also act as memory
>> barriers. By adding a type to the queues we can determine which
>> indices need to be protected.
>>
>> Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
>> ---
>>   drivers/infiniband/sw/rxe/rxe_cq.c    |  4 +++-
>>   drivers/infiniband/sw/rxe/rxe_qp.c    | 12 ++++++++----
>>   drivers/infiniband/sw/rxe/rxe_queue.c |  8 ++++----
>>   drivers/infiniband/sw/rxe/rxe_queue.h | 13 ++++++++++---
>>   drivers/infiniband/sw/rxe/rxe_srq.c   |  4 +++-
>>   5 files changed, 28 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/infiniband/sw/rxe/rxe_cq.c b/drivers/infiniband/sw/rxe/rxe_cq.c
>> index b315ebf041ac..1d4d8a31bc12 100644
>> --- a/drivers/infiniband/sw/rxe/rxe_cq.c
>> +++ b/drivers/infiniband/sw/rxe/rxe_cq.c
>> @@ -59,9 +59,11 @@ int rxe_cq_from_init(struct rxe_dev *rxe, struct rxe_cq *cq, int cqe,
>>                       struct rxe_create_cq_resp __user *uresp)
>>   {
>>          int err;
>> +       enum queue_type type;
>>
>> +       type = uresp ? QUEUE_TYPE_TO_USER : QUEUE_TYPE_KERNEL;
> When is QUEUE_TYPE_TO_USER used? and when is QUEUE_TYPE_FROM_USER is used?
>
> Zhu Yanjun


QUEUE_TYPE_FROM_USER is used for user space send, recv and shared 
receive work queues. QUEUE_TYPE_TO_USER is used for user space 
completion queues. QUEUE_TYPE_KERNEL is used for kernel verbs consumers 
for any queue.

Bob

>