RDMA/cxgb4: fix accept failure due to increased cpl_t5_pass_accept_rpl size

Commit 'c2ed5611afd7' has increased the cpl_t5_pass_accept_rpl{} structure
size by 8B to avoid roundup. cpl_t5_pass_accept_rpl{} is a HW specific
structure and increasing its size will lead to unwanted adapter errors.
Current commit reverts the cpl_t5_pass_accept_rpl{} back to its original
and allocates zeroed skb buffer there by avoiding the memset for iss field.
Reorder code to minimize chip type checks.

Fixes: c2ed561 ("iw_cxgb4: Use memset_startat() for cpl_t5_pass_accept_rpl")
Link: https://lore.kernel.org/r/20220809184118.2029-1-rahul.lakkireddy@chelsio.com
Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: bharatpotnuri

drivers/infiniband/hw/cxgb4/cm.c

@@ -2468,31 +2468,24 @@ static int accept_cr(struct c4iw_ep *ep, struct sk_buff *skb,
 			opt2 |= CCTRL_ECN_V(1);
 	}
 
-	skb_get(skb);
-	rpl = cplhdr(skb);
 	if (!is_t4(adapter_type)) {
-		BUILD_BUG_ON(sizeof(*rpl5) != roundup(sizeof(*rpl5), 16));
-		skb_trim(skb, sizeof(*rpl5));
-		rpl5 = (void *)rpl;
-		INIT_TP_WR(rpl5, ep->hwtid);
-	} else {
-		skb_trim(skb, sizeof(*rpl));
-		INIT_TP_WR(rpl, ep->hwtid);
-	}
-	OPCODE_TID(rpl) = cpu_to_be32(MK_OPCODE_TID(CPL_PASS_ACCEPT_RPL,
-						    ep->hwtid));
-
-	if (CHELSIO_CHIP_VERSION(adapter_type) > CHELSIO_T4) {
 		u32 isn = (prandom_u32() & ~7UL) - 1;
+
+		skb = get_skb(skb, roundup(sizeof(*rpl5), 16), GFP_KERNEL);
+		rpl5 = __skb_put_zero(skb, roundup(sizeof(*rpl5), 16));
+		rpl = (void *)rpl5;
+		INIT_TP_WR_CPL(rpl5, CPL_PASS_ACCEPT_RPL, ep->hwtid);
 		opt2 |= T5_OPT_2_VALID_F;
 		opt2 |= CONG_CNTRL_V(CONG_ALG_TAHOE);
 		opt2 |= T5_ISS_F;
-		rpl5 = (void *)rpl;
-		memset_after(rpl5, 0, iss);
 		if (peer2peer)
 			isn += 4;
 		rpl5->iss = cpu_to_be32(isn);
 		pr_debug("iss %u\n", be32_to_cpu(rpl5->iss));
+	} else {
+		skb = get_skb(skb, sizeof(*rpl), GFP_KERNEL);
+		rpl = __skb_put_zero(skb, sizeof(*rpl));
+		INIT_TP_WR_CPL(rpl, CPL_PASS_ACCEPT_RPL, ep->hwtid);
 	}
 
 	rpl->opt0 = cpu_to_be64(opt0);

drivers/net/ethernet/chelsio/cxgb4/t4_msg.h

@@ -497,7 +497,7 @@ struct cpl_t5_pass_accept_rpl {
 	__be32 opt2;
 	__be64 opt0;
 	__be32 iss;
-	__be32 rsvd[3];
+	__be32 rsvd;
 };
 
 struct cpl_act_open_req {