Re: [PATCH] RDMA/rxe: Fix responder length checking for UD request packets

[Zhu Yanjun <yanjun.zhu@linux.dev>]

On 30.05.24 16:17, Leon Romanovsky wrote:
> On Thu, 23 May 2024 17:46:17 +0800, Honggang LI wrote:
>> According to the IBA specification:
>> If a UD request packet is detected with an invalid length, the request
>> shall be an invalid request and it shall be silently dropped by
>> the responder. The responder then waits for a new request packet.
>>
>> commit 689c5421bfe0 ("RDMA/rxe: Fix incorrect responder length checking")
>> defers responder length check for UD QPs in function `copy_data`.
>> But it introduces a regression issue for UD QPs.
>>
>> [...]
> Applied, thanks!
>
> [1/1] RDMA/rxe: Fix responder length checking for UD request packets
>        https://git.kernel.org/rdma/rdma/c/05301cb42a5567

Hi, Leon

When I built this commit with gcc (Debian 8.3.0-6) 8.3.0, the following 
warnings will pop out.

"
drivers/infiniband/sw/rxe/rxe_resp.c: In function ‘rxe_resp_check_length’:
drivers/infiniband/sw/rxe/rxe_resp.c:401:3: error: ‘for’ loop initial 
declarations are only allowed in C99 or C11 mode
    for (int i = 0; i < qp->resp.wqe->dma.num_sge; i++)
    ^~~
drivers/infiniband/sw/rxe/rxe_resp.c:401:3: note: use option -std=c99, 
-std=gnu99, -std=c11 or -std=gnu11 to compile your code
"

The following diff will fix this problem.

"

diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c 
b/drivers/infiniband/sw/rxe/rxe_resp.c
index ad3c7bf76752..6596a85723c9 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -345,10 +345,11 @@ static enum resp_states 
rxe_resp_check_length(struct rxe_qp *qp,
          * length checks are performed in check_rkey.
          */
         if ((qp_type(qp) == IB_QPT_GSI) || (qp_type(qp) == IB_QPT_UD)) {
-               unsigned int recv_buffer_len = 0;
                 unsigned int payload = payload_size(pkt);
+               unsigned int recv_buffer_len = 0;
+               int i;

-               for (int i = 0; i < qp->resp.wqe->dma.num_sge; i++)
+               for (i = 0; i < qp->resp.wqe->dma.num_sge; i++)
                         recv_buffer_len += qp->resp.wqe->dma.sge[i].length;
                 if (payload + 40 > recv_buffer_len) {
                         rxe_dbg_qp(qp, "The receive buffer is too small 
for this UD packet.\n");

"

Zhu Yanjun

>
> Best regards,

-- 
Best Regards,
Yanjun.Zhu