[PATCH 7/7] RDMA/rxe: Extend ICRC to support nonlinear skbs

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Make ICRC calculations aware of potential non-linear skbs.
This is a step towards getting rid of skb_linearize() and its
extra data copy.

Signed-off-by: Bob Pearson <rpearsonhpe@xxxxxxxxx>
---
 drivers/infiniband/sw/rxe/rxe_icrc.c | 150 +++++++++++++++++----------
 drivers/infiniband/sw/rxe/rxe_loc.h  |   4 +-
 drivers/infiniband/sw/rxe/rxe_net.c  |   7 +-
 drivers/infiniband/sw/rxe/rxe_recv.c |   2 +-
 4 files changed, 103 insertions(+), 60 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_icrc.c b/drivers/infiniband/sw/rxe/rxe_icrc.c
index f5ebd9d23d12..d730c76bbeae 100644
--- a/drivers/infiniband/sw/rxe/rxe_icrc.c
+++ b/drivers/infiniband/sw/rxe/rxe_icrc.c
@@ -63,97 +63,134 @@ static __be32 rxe_crc32(struct rxe_dev *rxe, __be32 crc, void *addr,
 }
 
 /**
- * rxe_icrc_hdr - Compute a partial ICRC for the IB transport headers.
+ * rxe_icrc_packet - Compute the ICRC for a packet
  * @skb: packet buffer
  * @pkt: packet information
+ * @icrcp: pointer to returned ICRC
  *
- * Returns the partial ICRC
+ * Support linear or nonlinear skbs with frags
+ *
+ * Returns ICRC in *icrcp and 0 if no error occurs
+ * else returns an error.
  * For details see the InfiniBand Architecture spec and Annex 17
  * the RoCE v2 spec.
  */
-static __be32 rxe_icrc_hdr(struct sk_buff *skb, struct rxe_pkt_info *pkt)
+static int rxe_icrc_packet(struct sk_buff *skb, struct rxe_pkt_info *pkt,
+				__be32 *icrcp)
 {
+	struct skb_shared_info *info = skb_shinfo(skb);
+	struct rxe_dev *rxe = pkt->rxe;
+	struct iphdr *ip4h;
+	struct ipv6hdr *ip6h;
 	struct udphdr *udph;
 	struct rxe_bth *bth;
-	__be32 crc;
-	int length;
-	int hdr_size = sizeof(struct udphdr) +
+	__be32 icrc;
+	int hdr_size;
+	u8 pseudo_hdr[128];
+	int resid;
+	int bytes;
+	int nfrag;
+	skb_frag_t *frag;
+	u8 *addr;
+	int page_offset;
+	int start;
+	int len;
+	int ret;
+
+	hdr_size = rxe_opcode[pkt->opcode].length + sizeof(struct udphdr) +
 		(skb->protocol == htons(ETH_P_IP) ?
-		sizeof(struct iphdr) : sizeof(struct ipv6hdr));
-	/* pseudo header buffer size is calculate using ipv6 header size since
-	 * it is bigger than ipv4
-	 */
-	u8 pshdr[sizeof(struct udphdr) +
-		sizeof(struct ipv6hdr) +
-		RXE_BTH_BYTES];
-
-	/* This seed is the result of computing a CRC with a seed of
-	 * 0xfffffff and 8 bytes of 0xff representing a masked LRH.
-	 */
-	crc = 0xdebb20e3;
+			sizeof(struct iphdr) : sizeof(struct ipv6hdr));
 
-	if (skb->protocol == htons(ETH_P_IP)) { /* IPv4 */
-		struct iphdr *ip4h;
+	start = skb->network_header + skb->head - skb->data;
+	ret = skb_copy_bits(skb, start, pseudo_hdr, hdr_size);
+	if (unlikely(ret)) {
+		pr_warn_ratelimited("Malformed skb\n");
+		return ret;
+	}
 
-		memcpy(pshdr, ip_hdr(skb), hdr_size);
-		ip4h = (struct iphdr *)pshdr;
+	if (skb->protocol == htons(ETH_P_IP)) { /* IPv4 */
+		ip4h = (struct iphdr *)pseudo_hdr;
 		udph = (struct udphdr *)(ip4h + 1);
+		bth = (struct rxe_bth *)(udph + 1);
 
 		ip4h->ttl = 0xff;
 		ip4h->check = CSUM_MANGLED_0;
 		ip4h->tos = 0xff;
 	} else {				/* IPv6 */
-		struct ipv6hdr *ip6h;
-
-		memcpy(pshdr, ipv6_hdr(skb), hdr_size);
-		ip6h = (struct ipv6hdr *)pshdr;
+		ip6h = (struct ipv6hdr *)pseudo_hdr;
 		udph = (struct udphdr *)(ip6h + 1);
+		bth = (struct rxe_bth *)(udph + 1);
 
-		memset(ip6h->flow_lbl, 0xff, sizeof(ip6h->flow_lbl));
 		ip6h->priority = 0xf;
 		ip6h->hop_limit = 0xff;
 	}
 
 	udph->check = CSUM_MANGLED_0;
-
-	bth = (struct rxe_bth *)(udph + 1);
-	memcpy(bth, pkt->hdr, RXE_BTH_BYTES);
-
-	/* exclude bth.resv8a */
 	bth->qpn |= cpu_to_be32(~BTH_QPN_MASK);
 
-	length = hdr_size + RXE_BTH_BYTES;
-	crc = rxe_crc32(pkt->rxe, crc, pshdr, length);
+	icrc = 0xdebb20e3;
+	icrc = rxe_crc32(pkt->rxe, icrc, pseudo_hdr, hdr_size);
+
+	resid = (payload_size(pkt) + 0x3) & ~0x3;
+	nfrag = -1;
+
+	while (resid) {
+		if (nfrag < 0) {
+			addr = skb_network_header(skb) + hdr_size;
+			len = skb_tail_pointer(skb) - skb_network_header(skb);
+		} else if (nfrag < info->nr_frags) {
+			frag = &info->frags[nfrag];
+			page_offset = frag->bv_offset + hdr_size;
+			addr = kmap_atomic(frag->bv_page) + page_offset;
+			len = frag->bv_len;
+		} else {
+			pr_warn_ratelimited("Malformed skb\n");
+			return -EINVAL;
+		}
+
+		bytes = len - hdr_size;
+		if (bytes > 0) {
+			if (bytes > resid)
+				bytes = resid;
+			icrc = rxe_crc32(rxe, icrc, addr, bytes);
+			resid -= bytes;
+			hdr_size = 0;
+		} else {
+			hdr_size -= len;
+		}
+
+		if (nfrag++ >= 0)
+			kunmap_atomic(addr);
+	}
+
+	*icrcp = ~icrc;
 
-	/* And finish to compute the CRC on the remainder of the headers. */
-	crc = rxe_crc32(pkt->rxe, crc, pkt->hdr + RXE_BTH_BYTES,
-			rxe_opcode[pkt->opcode].length - RXE_BTH_BYTES);
-	return crc;
+	return 0;
 }
 
 /**
  * rxe_check_icrc - Compute ICRC for a packet and compare to the ICRC
- *		    delivered in the packet.
- * @skb: packet buffer with packet info in cb[] (receive path)
+ *		    in the packet.
+ * @skb: packet buffer
+ * @pkt: packet information
  *
  * Returns 0 if the ICRCs match or an error on failure
  */
-int rxe_icrc_check(struct sk_buff *skb)
+int rxe_icrc_check(struct sk_buff *skb, struct rxe_pkt_info *pkt)
 {
-	struct rxe_pkt_info *pkt = SKB_TO_PKT(skb);
 	__be32 *icrcp;
 	__be32 packet_icrc;
-	__be32 computed_icrc;
+	__be32 icrc;
+	int ret;
 
 	icrcp = (__be32 *)(pkt->hdr + pkt->paylen - RXE_ICRC_SIZE);
 	packet_icrc = *icrcp;
 
-	computed_icrc = rxe_icrc_hdr(skb, pkt);
-	computed_icrc = rxe_crc32(pkt->rxe, computed_icrc,
-		(u8 *)payload_addr(pkt), payload_size(pkt) + bth_pad(pkt));
-	computed_icrc = ~computed_icrc;
+	ret = rxe_icrc_packet(skb, pkt, &icrc);
+	if (unlikely(ret))
+		return ret;
 
-	if (unlikely(computed_icrc != packet_icrc)) {
+	if (unlikely(icrc != packet_icrc)) {
 		if (skb->protocol == htons(ETH_P_IPV6))
 			pr_warn_ratelimited("bad ICRC from %pI6c\n",
 					    &ipv6_hdr(skb)->saddr);
@@ -162,7 +199,6 @@ int rxe_icrc_check(struct sk_buff *skb)
 					    &ip_hdr(skb)->saddr);
 		else
 			pr_warn_ratelimited("bad ICRC from unknown\n");
-
 		return -EINVAL;
 	}
 
@@ -174,15 +210,19 @@ int rxe_icrc_check(struct sk_buff *skb)
  *		       correct position after the payload and pad.
  * @skb: packet buffer
  * @pkt: packet information
+ *
+ * Returns 0 on success or an error
  */
-void rxe_icrc_generate(struct sk_buff *skb, struct rxe_pkt_info *pkt)
+int rxe_icrc_generate(struct sk_buff *skb, struct rxe_pkt_info *pkt)
 {
 	__be32 *icrcp;
-	__be32 icrc;
+	int ret;
 
 	icrcp = (__be32 *)(pkt->hdr + pkt->paylen - RXE_ICRC_SIZE);
-	icrc = rxe_icrc_hdr(skb, pkt);
-	icrc = rxe_crc32(pkt->rxe, icrc, (u8 *)payload_addr(pkt),
-				payload_size(pkt) + bth_pad(pkt));
-	*icrcp = ~icrc;
+
+	ret = rxe_icrc_packet(skb, pkt, icrcp);
+	if (unlikely(ret))
+		return ret;
+
+	return 0;
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index e8e87336469b..09836cdb1e89 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -194,8 +194,8 @@ int rxe_responder(void *arg);
 
 /* rxe_icrc.c */
 int rxe_icrc_init(struct rxe_dev *rxe);
-int rxe_icrc_check(struct sk_buff *skb);
-void rxe_icrc_generate(struct sk_buff *skb, struct rxe_pkt_info *pkt);
+int rxe_icrc_check(struct sk_buff *skb, struct rxe_pkt_info *pkt);
+int rxe_icrc_generate(struct sk_buff *skb, struct rxe_pkt_info *pkt);
 
 void rxe_resp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb);
 
diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
index 4d109e5b33ff..d708ff19e774 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -434,8 +434,11 @@ int rxe_xmit_packet(struct rxe_qp *qp, struct rxe_pkt_info *pkt,
 		goto drop;
 	}
 
-	if (rxe_must_generate_icrc)
-		rxe_icrc_generate(skb, pkt);
+	if (rxe_must_generate_icrc) {
+		err = rxe_icrc_generate(skb, pkt);
+		if (unlikely(err))
+			goto drop;
+	}
 
 	if (pkt->mask & RXE_LOOPBACK_MASK) {
 		memcpy(SKB_TO_PKT(skb), pkt, sizeof(*pkt));
diff --git a/drivers/infiniband/sw/rxe/rxe_recv.c b/drivers/infiniband/sw/rxe/rxe_recv.c
index 01d425b3991e..7f51b9e92437 100644
--- a/drivers/infiniband/sw/rxe/rxe_recv.c
+++ b/drivers/infiniband/sw/rxe/rxe_recv.c
@@ -383,7 +383,7 @@ void rxe_rcv(struct sk_buff *skb)
 		goto drop;
 
 	if (rxe_must_check_icrc) {
-		err = rxe_icrc_check(skb);
+		err = rxe_icrc_check(skb, pkt);
 		if (unlikely(err))
 			goto drop;
 	}
-- 
2.30.2




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