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

Bob Pearson
2021-06-29T20:14:29Z

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@gmail.com>
---
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