[PATCH 2/6] RDMA/rxe: consolidate code for calculating ICRC of packets

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

Since rxe_icrc_hdr() is always immediately followed by updating the CRC
with the packet's payload, just rename it to rxe_icrc() and make it
include the payload in the CRC, so it now handles the entire packet.

This is a refactor with no change in behavior.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 drivers/infiniband/sw/rxe/rxe_icrc.c | 36 ++++++++++++----------------
 1 file changed, 15 insertions(+), 21 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_icrc.c b/drivers/infiniband/sw/rxe/rxe_icrc.c
index ee417a0bbbdca..c7b0b4673b959 100644
--- a/drivers/infiniband/sw/rxe/rxe_icrc.c
+++ b/drivers/infiniband/sw/rxe/rxe_icrc.c
@@ -60,26 +60,24 @@ static u32 rxe_crc32(struct rxe_dev *rxe, u32 crc, void *next, size_t len)
 
 	return icrc;
 }
 
 /**
- * rxe_icrc_hdr() - Compute the partial ICRC for the network and transport
- *		  headers of a packet.
+ * rxe_icrc() - Compute the ICRC of a packet
  * @skb: packet buffer
  * @pkt: packet information
  *
- * Return: the partial ICRC
+ * Return: the ICRC
  */
-static u32 rxe_icrc_hdr(struct sk_buff *skb, struct rxe_pkt_info *pkt)
+static u32 rxe_icrc(struct sk_buff *skb, struct rxe_pkt_info *pkt)
 {
 	unsigned int bth_offset = 0;
 	struct iphdr *ip4h = NULL;
 	struct ipv6hdr *ip6h = NULL;
 	struct udphdr *udph;
 	struct rxe_bth *bth;
 	u32 crc;
-	int length;
 	int hdr_size = 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
@@ -118,17 +116,23 @@ static u32 rxe_icrc_hdr(struct sk_buff *skb, struct rxe_pkt_info *pkt)
 	bth = (struct rxe_bth *)&pshdr[bth_offset];
 
 	/* 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);
+	/* Update the CRC with the first part of the headers. */
+	crc = rxe_crc32(pkt->rxe, crc, pshdr, hdr_size + RXE_BTH_BYTES);
 
-	/* And finish to compute the CRC on the remainder of the headers. */
+	/* Update the CRC with 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;
+
+	/* Update the CRC with the payload. */
+	crc = rxe_crc32(pkt->rxe, crc, payload_addr(pkt),
+			payload_size(pkt) + bth_pad(pkt));
+
+	/* Invert the CRC and return it. */
+	return ~crc;
 }
 
 /**
  * rxe_icrc_check() - Compute ICRC for a packet and compare to the ICRC
  *		      delivered in the packet.
@@ -146,18 +150,12 @@ int rxe_icrc_check(struct sk_buff *skb, struct rxe_pkt_info *pkt)
 	 * descending order from the x^31 coefficient to the x^0 one.  When the
 	 * result is interpreted as a 32-bit integer using the required reverse
 	 * mapping between bits and polynomial coefficients, it's a __le32.
 	 */
 	__le32 *icrcp = (__le32 *)(pkt->hdr + pkt->paylen - RXE_ICRC_SIZE);
-	u32 icrc;
 
-	icrc = rxe_icrc_hdr(skb, pkt);
-	icrc = rxe_crc32(pkt->rxe, icrc, (u8 *)payload_addr(pkt),
-				payload_size(pkt) + bth_pad(pkt));
-	icrc = ~icrc;
-
-	if (unlikely(icrc != le32_to_cpu(*icrcp)))
+	if (unlikely(rxe_icrc(skb, pkt) != le32_to_cpu(*icrcp)))
 		return -EINVAL;
 
 	return 0;
 }
 
@@ -167,12 +165,8 @@ int rxe_icrc_check(struct sk_buff *skb, struct rxe_pkt_info *pkt)
  * @pkt: packet information
  */
 void rxe_icrc_generate(struct sk_buff *skb, struct rxe_pkt_info *pkt)
 {
 	__le32 *icrcp = (__le32 *)(pkt->hdr + pkt->paylen - RXE_ICRC_SIZE);
-	u32 icrc;
 
-	icrc = rxe_icrc_hdr(skb, pkt);
-	icrc = rxe_crc32(pkt->rxe, icrc, (u8 *)payload_addr(pkt),
-				payload_size(pkt) + bth_pad(pkt));
-	*icrcp = cpu_to_le32(~icrc);
+	*icrcp = cpu_to_le32(rxe_icrc(skb, pkt));
 }
-- 
2.48.1