Re: [PATCH 1/3] RDMA/rxe: Use sizeof instead of hard code number

From: Zhu Yanjun
Date: Thu Aug 22 2024 - 07:59:55 EST


在 2024/8/22 14:52, zhenwei pi 写道:
Use 'sizeof(union rdma_network_hdr)' instead of hard code GRH length
for GSI and UD.

Signed-off-by: zhenwei pi <pizhenwei@xxxxxxxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_resp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 6596a85723c9..bf8f4bc8c5c8 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -351,7 +351,7 @@ static enum resp_states rxe_resp_check_length(struct rxe_qp *qp,
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) {
+ if (payload + sizeof(union rdma_network_hdr) > recv_buffer_len) {

The definition of union rdma_network_hdr is as below

797 union rdma_network_hdr {
798 struct ib_grh ibgrh;
799 struct {
800 /* The IB spec states that if it's IPv4, the header
801 * is located in the last 20 bytes of the header.
802 */
803 u8 reserved[20];
804 struct iphdr roce4grh;
805 };
806 };

The length is 40 byte.

But in this,

sizeof(struct iphdr) (20) + sizeof(struct udphdr) (8) + sizeof(struct rxe_bth) (12) = 40

Not sure if we should use sizeof(union rdma_network_hdr) or (sizeof(struct iphdr) + sizeof(struct udphdr) + sizeof(struct rxe_bth)) in this place.

Best Regards,
Zhu Yanjun


rxe_dbg_qp(qp, "The receive buffer is too small for this UD packet.\n");
return RESPST_ERR_LENGTH;
}