| Message ID | 20200930162010.21610-4-borisp@mellanox.com |
|---|---|
| State | RFC |
| Delegated to: | David Miller |
| Headers | show |
| Series | nvme-tcp receive offloads | expand |
> This commit itroduces support for CRC offload to direct data placement introduces > ULP on the receive side. Both DDP and CRC share a common API to > initialize the offload for a TCP socket. But otherwise, both can > be executed independently. From the API it not clear that the offload engine does crc32c, do you see this extended to other crc types in the future? Other than this the patch looks good to me, Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
On 09/10/2020 0:51, Sagi Grimberg wrote: >> This commit itroduces support for CRC offload to direct data placement > introduces >> ULP on the receive side. Both DDP and CRC share a common API to >> initialize the offload for a TCP socket. But otherwise, both can >> be executed independently. > From the API it not clear that the offload engine does crc32c, do you > see this extended to other crc types in the future? Yes, it is somewhat implicit, and it depends on the tcp ddp configuration. At the moment we only do nvme-tcp, and that has only CRC32C. If in the future, there would be other CRC variants, or data digest algorithms, then the code could be easily extended. In general, any data digest over TCP can leverage this code and SKB member. Not only other CRC types can benefit from it, but even more complex data digest algorithms like SHA can use this. In essence this bit is similar to the TLS skb->decrypted bit. In TLS, skb->decrypted also indicates that the authentication has no error, exactly like ddp_crc indicates that there is no CRC32C error. The only reason we didn't use the same bit for both is that these two protocol offloads can be combined and that will benefit from two independent bits. > > Other than this the patch looks good to me, > Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h index a0074b244372..27001f5c0be1 100644 --- a/include/linux/netdev_features.h +++ b/include/linux/netdev_features.h @@ -85,6 +85,7 @@ enum { NETIF_F_HW_MACSEC_BIT, /* Offload MACsec operations */ NETIF_F_HW_TCP_DDP_BIT, /* TCP direct data placement offload */ + NETIF_F_HW_TCP_DDP_CRC_BIT, /* TCP DDP CRC offload */ /* * Add your fresh new feature above and remember to update @@ -159,6 +160,7 @@ enum { #define NETIF_F_GSO_FRAGLIST __NETIF_F(GSO_FRAGLIST) #define NETIF_F_HW_MACSEC __NETIF_F(HW_MACSEC) #define NETIF_F_HW_TCP_DDP __NETIF_F(HW_TCP_DDP) +#define NETIF_F_HW_TCP_DDP_CRC __NETIF_F(HW_TCP_DDP_CRC) /* Finds the next feature with the highest number of the range of start till 0. */ diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 04a18e01b362..0530d849ebf2 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -858,6 +858,10 @@ struct sk_buff { #ifdef CONFIG_TLS_DEVICE __u8 decrypted:1; #endif +#ifdef CONFIG_TCP_DDP_CRC + __u8 ddp_crc:1; +#endif + #ifdef CONFIG_NET_SCHED __u16 tc_index; /* traffic control index */ diff --git a/net/Kconfig b/net/Kconfig index 346e9fa7a6ec..7891b4380e56 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -468,6 +468,14 @@ config TCP_DDP NVMe-TCP/iSCSI, to request the NIC to place TCP payload data of a command response directly into kernel pages. +config TCP_DDP_CRC + bool "TCP direct data placement CRC offload" + default n + help + Direct Data Placement (DDP) CRC32C offload for TCP enables ULP, such as + NVMe-TCP/iSCSI, to request the NIC to calculate/verify the data digest + of commands as they go through the NIC. Thus avoiding the costly + per-byte overhead. endif # if NET diff --git a/net/ethtool/common.c b/net/ethtool/common.c index a2ff7a4a6bbf..4941670dd25d 100644 --- a/net/ethtool/common.c +++ b/net/ethtool/common.c @@ -69,6 +69,7 @@ const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN] = { [NETIF_F_GRO_FRAGLIST_BIT] = "rx-gro-list", [NETIF_F_HW_MACSEC_BIT] = "macsec-hw-offload", [NETIF_F_HW_TCP_DDP_BIT] = "tcp-ddp-offload", + [NETIF_F_HW_TCP_DDP_CRC_BIT] = "tcp-ddp-crc-offload", }; const char diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index f7b3e37d2198..f8e1e8ebef2c 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5099,6 +5099,9 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root, memcpy(nskb->cb, skb->cb, sizeof(skb->cb)); #ifdef CONFIG_TLS_DEVICE nskb->decrypted = skb->decrypted; +#endif +#ifdef CONFIG_TCP_DDP_CRC + nskb->ddp_crc = skb->ddp_crc; #endif TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start; if (list) @@ -5132,6 +5135,10 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root, #ifdef CONFIG_TLS_DEVICE if (skb->decrypted != nskb->decrypted) goto end; +#endif +#ifdef CONFIG_TCP_DDP_CRC + if (skb->ddp_crc != nskb->ddp_crc) + goto end; #endif } } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index ace48b2790ff..2693029e6ee7 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1791,6 +1791,9 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) || #ifdef CONFIG_TLS_DEVICE tail->decrypted != skb->decrypted || +#endif +#ifdef CONFIG_TCP_DDP_CRC + tail->ddp_crc != skb->ddp_crc || #endif thtail->doff != th->doff || memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th))) diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index e09147ac9a99..39f5f0bcf181 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -262,6 +262,9 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb) #ifdef CONFIG_TLS_DEVICE flush |= p->decrypted ^ skb->decrypted; #endif +#ifdef CONFIG_TCP_DDP_CRC + flush |= p->ddp_crc ^ skb->ddp_crc; +#endif if (flush || skb_gro_receive(p, skb)) { mss = 1;