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From: David Gibson <david@gibson.dropbear.id.au>
To: Laurent Vivier <lvivier@redhat.com>
Cc: passt-dev@passt.top
Subject: Re: [PATCH 04/24] checksum: add csum_iov()
Date: Mon, 5 Feb 2024 17:07:47 +1100	[thread overview]
Message-ID: <ZcB7Mx9LW_ek5bD_@zatzit> (raw)
In-Reply-To: <20240202141151.3762941-5-lvivier@redhat.com>

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On Fri, Feb 02, 2024 at 03:11:31PM +0100, Laurent Vivier wrote:
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  checksum.c | 39 ++++++++++++++++++++++-----------------
>  checksum.h |  1 +
>  2 files changed, 23 insertions(+), 17 deletions(-)
> 
> diff --git a/checksum.c b/checksum.c
> index c94980771c63..14b6057684d9 100644
> --- a/checksum.c
> +++ b/checksum.c
> @@ -395,17 +395,8 @@ less_than_128_bytes:
>  	return (uint32_t)sum64;
>  }
>  
> -/**
> - * csum() - Compute TCP/IP-style checksum
> - * @buf:	Input buffer, must be aligned to 32-byte boundary
> - * @len:	Input length
> - * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
> - *
> - * Return: 16-bit folded, complemented checksum sum
> - */
> -/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
>  __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
> -uint16_t csum(const void *buf, size_t len, uint32_t init)
> +uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init)

I'm wondering if this might be a little clearer with a feed() /
final() interface something like siphash.

>  {
>  	intptr_t align = ((intptr_t)buf + 0x1f) & ~(intptr_t)0x1f;
>  	unsigned int pad = align - (intptr_t)buf;
> @@ -419,24 +410,38 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
>  	if (len > pad)
>  		init = csum_avx2((void *)align, len - pad, init);
>  
> -	return (uint16_t)~csum_fold(init);
> +	return init;
>  }
> -
>  #else /* __AVX2__ */
>  
> +__attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
> +uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init)
> +{
> +	return sum_16b(buf, len) + init;
> +}
> +#endif /* !__AVX2__ */
> +
>  /**
>   * csum() - Compute TCP/IP-style checksum
> - * @buf:	Input buffer
> + * @buf:	Input buffer, must be aligned to 32-byte boundary

I thought the point of the previous patch was that this didn't have to
be 32-byte aligned any more.

>   * @len:	Input length
> - * @sum:	Initial 32-bit checksum, 0 for no pre-computed checksum
> + * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
>   *
> - * Return: 16-bit folded, complemented checksum
> + * Return: 16-bit folded, complemented checksum sum

"checksum sum"

>   */
>  /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
>  __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
>  uint16_t csum(const void *buf, size_t len, uint32_t init)
>  {
> -	return csum_unaligned(buf, len, init);
> +	return (uint16_t)~csum_fold(csum_unfolded(buf, len, init));
>  }
>  
> -#endif /* !__AVX2__ */
> +uint16_t csum_iov(struct iovec *iov, unsigned int n, uint32_t init)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < n;  i++)
> +		init = csum_unfolded(iov[i].iov_base, iov[i].iov_len, init);
> +
> +	return (uint16_t)~csum_fold(init);
> +}
> diff --git a/checksum.h b/checksum.h
> index 21c0310d3804..6a20297a5826 100644
> --- a/checksum.h
> +++ b/checksum.h
> @@ -25,5 +25,6 @@ void csum_icmp6(struct icmp6hdr *icmp6hr,
>  		const struct in6_addr *saddr, const struct in6_addr *daddr,
>  		const void *payload, size_t len);
>  uint16_t csum(const void *buf, size_t len, uint32_t init);
> +uint16_t csum_iov(struct iovec *iov, unsigned int n, uint32_t init);
>  
>  #endif /* CHECKSUM_H */

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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  reply	other threads:[~2024-02-05  6:13 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-02 14:11 [PATCH 00/24] Add vhost-user support to passt Laurent Vivier
2024-02-02 14:11 ` [PATCH 01/24] iov: add some functions to manage iovec Laurent Vivier
2024-02-05  5:57   ` David Gibson
2024-02-06 14:28     ` Laurent Vivier
2024-02-07  1:01       ` David Gibson
2024-02-07 10:00         ` Laurent Vivier
2024-02-06 16:10   ` Stefano Brivio
2024-02-07 14:02     ` Laurent Vivier
2024-02-07 14:57       ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 02/24] pcap: add pcap_iov() Laurent Vivier
2024-02-05  6:25   ` David Gibson
2024-02-06 16:10   ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 03/24] checksum: align buffers Laurent Vivier
2024-02-05  6:02   ` David Gibson
2024-02-07  9:01     ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 04/24] checksum: add csum_iov() Laurent Vivier
2024-02-05  6:07   ` David Gibson [this message]
2024-02-07  9:02   ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 05/24] util: move IP stuff from util.[ch] to ip.[ch] Laurent Vivier
2024-02-05  6:13   ` David Gibson
2024-02-07  9:03     ` Stefano Brivio
2024-02-08  0:04       ` David Gibson
2024-02-02 14:11 ` [PATCH 06/24] ip: move duplicate IPv4 checksum function to ip.h Laurent Vivier
2024-02-05  6:16   ` David Gibson
2024-02-07 10:40   ` Stefano Brivio
2024-02-07 23:43     ` David Gibson
2024-02-02 14:11 ` [PATCH 07/24] ip: introduce functions to compute the header part checksum for TCP/UDP Laurent Vivier
2024-02-05  6:20   ` David Gibson
2024-02-07 10:41   ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 08/24] tcp: extract buffer management from tcp_send_flag() Laurent Vivier
2024-02-06  0:24   ` David Gibson
2024-02-08 16:57   ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 09/24] tcp: extract buffer management from tcp_conn_tap_mss() Laurent Vivier
2024-02-06  0:47   ` David Gibson
2024-02-08 16:59   ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 10/24] tcp: rename functions that manage buffers Laurent Vivier
2024-02-06  1:48   ` David Gibson
2024-02-08 17:10     ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 11/24] tcp: move buffers management functions to their own file Laurent Vivier
2024-02-02 14:11 ` [PATCH 12/24] tap: make tap_update_mac() generic Laurent Vivier
2024-02-06  1:49   ` David Gibson
2024-02-08 17:10     ` Stefano Brivio
2024-02-09  5:02       ` David Gibson
2024-02-02 14:11 ` [PATCH 13/24] tap: export pool_flush()/tapX_handler()/packet_add() Laurent Vivier
2024-02-02 14:29   ` Laurent Vivier
2024-02-06  1:52   ` David Gibson
2024-02-11 23:15   ` Stefano Brivio
2024-02-12  2:22     ` David Gibson
2024-02-02 14:11 ` [PATCH 14/24] udp: move udpX_l2_buf_t and udpX_l2_mh_sock out of udp_update_hdrX() Laurent Vivier
2024-02-06  1:59   ` David Gibson
2024-02-11 23:16   ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 15/24] udp: rename udp_sock_handler() to udp_buf_sock_handler() Laurent Vivier
2024-02-06  2:14   ` David Gibson
2024-02-11 23:17     ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 16/24] packet: replace struct desc by struct iovec Laurent Vivier
2024-02-06  2:25   ` David Gibson
2024-02-11 23:18     ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 17/24] vhost-user: compare mode MODE_PASTA and not MODE_PASST Laurent Vivier
2024-02-06  2:29   ` David Gibson
2024-02-02 14:11 ` [PATCH 18/24] vhost-user: introduce virtio API Laurent Vivier
2024-02-06  3:51   ` David Gibson
2024-02-11 23:18     ` Stefano Brivio
2024-02-12  2:26       ` David Gibson
2024-02-02 14:11 ` [PATCH 19/24] vhost-user: introduce vhost-user API Laurent Vivier
2024-02-07  2:13   ` David Gibson
2024-02-02 14:11 ` [PATCH 20/24] vhost-user: add vhost-user Laurent Vivier
2024-02-07  2:40   ` David Gibson
2024-02-11 23:19     ` Stefano Brivio
2024-02-12  2:47       ` David Gibson
2024-02-13 15:22         ` Stefano Brivio
2024-02-14  2:05           ` David Gibson
2024-02-11 23:19   ` Stefano Brivio
2024-02-12  2:49     ` David Gibson
2024-02-12 10:02       ` Laurent Vivier
2024-02-12 16:56         ` Stefano Brivio
2024-02-02 14:11 ` [PATCH 21/24] vhost-user: use guest buffer directly in vu_handle_tx() Laurent Vivier
2024-02-09  4:26   ` David Gibson
2024-02-02 14:11 ` [PATCH 22/24] tcp: vhost-user RX nocopy Laurent Vivier
2024-02-09  4:57   ` David Gibson
2024-02-02 14:11 ` [PATCH 23/24] udp: " Laurent Vivier
2024-02-09  5:00   ` David Gibson
2024-02-02 14:11 ` [PATCH 24/24] vhost-user: remove tap_send_frames_vu() Laurent Vivier
2024-02-09  5:01   ` David Gibson

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