Re: [dpdk-dev] [PATCH v2 2/2] mbuf: assign valid bit values for some RX and TX flags

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi Helin,

> -----Original Message-----
> From: Zhang, Helin
> Sent: Friday, December 05, 2014 1:46 AM
> To: dev@dpdk.org
> Cc: Cao, Waterman; Cao, Min; Wu, Jingjing; Liu, Jijiang; Ananyev, Konstantin; olivier.matz@6wind.com; Zhang, Helin
> Subject: [PATCH v2 2/2] mbuf: assign valid bit values for some RX and TX flags
> 
> Before redefining mbuf structure, there was lack of free bits in
> 'ol_flags' (32 bits in total) for new RX or TX flags. So it tried
> to reuse existant bits as most as possible, or even assigning 0 to
> some of bit flags. After new mbuf structure defined, there are
> quite a lot of free bits. So those newly added bit flags should be
> assigned with correct and valid bit values, and getting their names
> should be enabled as well. Note that 'RECIP' should be removed, as
> nowhere will use it.
> 
> Signed-off-by: Helin Zhang <helin.zhang@intel.com>
> ---
>  lib/librte_mbuf/rte_mbuf.c |  9 ++++-----
>  lib/librte_mbuf/rte_mbuf.h | 19 +++++++++----------
>  2 files changed, 13 insertions(+), 15 deletions(-)
> 
> v2 changes:
> * Removed error flag of 'ECIPE' processing only in mbuf. All other error flags
>   were added back.
> * Assigned error flags with correct and valid values, as their previous values
>   were invalid.
> * Enabled getting all error flag names.
> 
> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
> index 87c2963..3ce7c8d 100644
> --- a/lib/librte_mbuf/rte_mbuf.c
> +++ b/lib/librte_mbuf/rte_mbuf.c
> @@ -210,11 +210,10 @@ const char *rte_get_rx_ol_flag_name(uint64_t mask)
>  	case PKT_RX_FDIR: return "PKT_RX_FDIR";
>  	case PKT_RX_L4_CKSUM_BAD: return "PKT_RX_L4_CKSUM_BAD";
>  	case PKT_RX_IP_CKSUM_BAD: return "PKT_RX_IP_CKSUM_BAD";
> -	/* case PKT_RX_EIP_CKSUM_BAD: return "PKT_RX_EIP_CKSUM_BAD"; */
> -	/* case PKT_RX_OVERSIZE: return "PKT_RX_OVERSIZE"; */
> -	/* case PKT_RX_HBUF_OVERFLOW: return "PKT_RX_HBUF_OVERFLOW"; */
> -	/* case PKT_RX_RECIP_ERR: return "PKT_RX_RECIP_ERR"; */
> -	/* case PKT_RX_MAC_ERR: return "PKT_RX_MAC_ERR"; */
> +	case PKT_RX_EIP_CKSUM_BAD: return "PKT_RX_EIP_CKSUM_BAD";
> +	case PKT_RX_OVERSIZE: return "PKT_RX_OVERSIZE";
> +	case PKT_RX_HBUF_OVERFLOW: return "PKT_RX_HBUF_OVERFLOW";
> +	case PKT_RX_MAC_ERR: return "PKT_RX_MAC_ERR";
>  	case PKT_RX_IPV4_HDR: return "PKT_RX_IPV4_HDR";
>  	case PKT_RX_IPV4_HDR_EXT: return "PKT_RX_IPV4_HDR_EXT";
>  	case PKT_RX_IPV6_HDR: return "PKT_RX_IPV6_HDR";
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 2e5fce5..c9591c0 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -84,11 +84,6 @@ extern "C" {
>  #define PKT_RX_FDIR          (1ULL << 2)  /**< RX packet with FDIR match indicate. */
>  #define PKT_RX_L4_CKSUM_BAD  (1ULL << 3)  /**< L4 cksum of RX pkt. is not OK. */
>  #define PKT_RX_IP_CKSUM_BAD  (1ULL << 4)  /**< IP cksum of RX pkt. is not OK. */
> -#define PKT_RX_EIP_CKSUM_BAD (0ULL << 0)  /**< External IP header checksum error. */
> -#define PKT_RX_OVERSIZE      (0ULL << 0)  /**< Num of desc of an RX pkt oversize. */
> -#define PKT_RX_HBUF_OVERFLOW (0ULL << 0)  /**< Header buffer overflow. */
> -#define PKT_RX_RECIP_ERR     (0ULL << 0)  /**< Hardware processing error. */
> -#define PKT_RX_MAC_ERR       (0ULL << 0)  /**< MAC error. */
>  #define PKT_RX_IPV4_HDR      (1ULL << 5)  /**< RX packet with IPv4 header. */
>  #define PKT_RX_IPV4_HDR_EXT  (1ULL << 6)  /**< RX packet with extended IPv4 header. */
>  #define PKT_RX_IPV6_HDR      (1ULL << 7)  /**< RX packet with IPv6 header. */
> @@ -99,6 +94,10 @@ extern "C" {
>  #define PKT_RX_TUNNEL_IPV6_HDR (1ULL << 12) /**< RX tunnel packet with IPv6 header. */
>  #define PKT_RX_FDIR_ID       (1ULL << 13) /**< FD id reported if FDIR match. */
>  #define PKT_RX_FDIR_FLX      (1ULL << 14) /**< Flexible bytes reported if FDIR match. */
> +#define PKT_RX_EIP_CKSUM_BAD (1ULL << 15)  /**< External IP header checksum error. */
> +#define PKT_RX_OVERSIZE      (1ULL << 16)  /**< Num of desc of an RX pkt oversize. */
> +#define PKT_RX_HBUF_OVERFLOW (1ULL << 17)  /**< Header buffer overflow. */
> +#define PKT_RX_MAC_ERR       (1ULL << 18)  /**< MAC error. */
>  /* add new RX flags here */

I still think there is no point to have several flags to indicate HW error for the packet.
As I suggested before we can collapse 3 of them (OVERSIZE, HBUF_OVERFLOW, MAC_ERR) into one. 
As I remember, Oliver even suggested to drop such packets.
As was said above - if is not a whole packet SW can't do much with it anyway.
The only thing such bad packets can probably be used for - some sort of debugging.
So we probably can combine both things: 
- in normal operation just drop such packet 
- if PMD_DEBUG_RX is enabled, then write a log record, set RX_HW_ERR and deliver a packet to the upper layer.

> 
>  /* add new TX flags here */
> @@ -141,13 +140,13 @@ extern "C" {
>  #define PKT_TX_IP_CKSUM      (1ULL << 54) /**< IP cksum of TX pkt. computed by NIC. */
>  #define PKT_TX_IPV4_CSUM     PKT_TX_IP_CKSUM /**< Alias of PKT_TX_IP_CKSUM. */
> 
> -/** Tell the NIC it's an IPv4 packet. Required for L4 checksum offload or TSO. */
> -#define PKT_TX_IPV4          PKT_RX_IPV4_HDR
> +/** Tell the NIC it's an IPv4 packet. */
> +#define PKT_TX_IPV4          (1ULL << 55) /**< TX packet is a IPV4 packet. */
> 
> -/** Tell the NIC it's an IPv6 packet. Required for L4 checksum offload or TSO. */
> -#define PKT_TX_IPV6          PKT_RX_IPV6_HDR
> +/** Tell the NIC it's an IPv6 packet. */
> +#define PKT_TX_IPV6          (1ULL << 56) /**< TX packet is a IPV6 packet. */
> 
> -#define PKT_TX_VLAN_PKT      (1ULL << 55) /**< TX packet is a 802.1q VLAN packet. */
> +#define PKT_TX_VLAN_PKT      (1ULL << 57) /**< TX packet is a VLAN packet. */

I don't think these changes should be part of that patch.
They violate another patch that Frank sent before.

Konstantin

> 
>  /* Use final bit of flags to indicate a control mbuf */
>  #define CTRL_MBUF_FLAG       (1ULL << 63) /**< Mbuf contains control data */
> --
> 1.9.3