Re: [PATCH v5 09/12] icmp: Pass queue pair explicitly through ICMP send path

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Jun 16, 2026 at 02:51:27PM +0200, Laurent Vivier wrote:
> icmp_sock_handler() uses QPAIR_DEFAULT when calling tap_icmp4_send()
> and tap_icmp6_send().  Thread a qpair parameter from the caller in
> passt_worker() so the queue pair is selected at the entry point rather
> than hard-coded inside the handler.
> 
> passt_worker() currently passes QPAIR_DEFAULT, preserving existing
> single-queue behavior.  This is a preparatory step for per-queue
> worker threads in vhost-user mode.
> 
> No functional change.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  icmp.c  | 22 ++++++++++++++--------
>  icmp.h  |  7 ++++---
>  passt.c |  2 +-
>  tap.c   |  4 ++--
>  4 files changed, 21 insertions(+), 14 deletions(-)
> 
> diff --git a/icmp.c b/icmp.c
> index 3705f5ce0c9b..62038f977116 100644
> --- a/icmp.c
> +++ b/icmp.c
> @@ -66,8 +66,10 @@ static struct icmp_ping_flow *ping_at_sidx(flow_sidx_t sidx)
>   * icmp_sock_handler() - Handle new data from ICMP or ICMPv6 socket
>   * @c:		Execution context
>   * @ref:	epoll reference
> + * @qpair:	Queue pair to process
>   */
> -void icmp_sock_handler(const struct ctx *c, union epoll_ref ref)
> +void icmp_sock_handler(const struct ctx *c, union epoll_ref ref,
> +		       unsigned int qpair)

As in previous patches, why would the caller know the queue, before
we've look at the flow?

>  {
>  	struct icmp_ping_flow *pingf = ping_at_sidx(ref.flowside);
>  	const struct flowside *ini = &pingf->f.side[INISIDE];
> @@ -132,13 +134,13 @@ void icmp_sock_handler(const struct ctx *c, union epoll_ref ref)
>  		const struct in_addr *daddr = inany_v4(&ini->eaddr);
>  
>  		assert(saddr && daddr); /* Must have IPv4 addresses */
> -		tap_icmp4_send(c, QPAIR_DEFAULT, *saddr, *daddr, buf,
> +		tap_icmp4_send(c, qpair, *saddr, *daddr, buf,
>  			       pingf->f.tap_omac, n);
>  	} else if (pingf->f.type == FLOW_PING6) {
>  		const struct in6_addr *saddr = &ini->oaddr.a6;
>  		const struct in6_addr *daddr = &ini->eaddr.a6;
>  
> -		tap_icmp6_send(c, QPAIR_DEFAULT, saddr, daddr, buf,
> +		tap_icmp6_send(c, qpair, saddr, daddr, buf,
>  			       pingf->f.tap_omac, n);
>  	}
>  	return;
> @@ -163,6 +165,7 @@ static void icmp_ping_close(const struct ctx *c,
>  /**
>   * icmp_ping_new() - Prepare a new ping socket for a new id
>   * @c:		Execution context
> + * @qpair:	Queue pair of the flow
>   * @af:		Address family, AF_INET or AF_INET6
>   * @id:		ICMP id for the new socket
>   * @saddr:	Source address
> @@ -171,8 +174,9 @@ static void icmp_ping_close(const struct ctx *c,
>   * Return: newly opened ping flow, or NULL on failure
>   */
>  static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
> -					    sa_family_t af, uint16_t id,
> -					    const void *saddr, const void *daddr)
> +					    unsigned int qpair, sa_family_t af,
> +					    uint16_t id, const void *saddr,
> +					    const void *daddr)
>  {
>  	uint8_t proto = af == AF_INET ? IPPROTO_ICMP : IPPROTO_ICMPV6;
>  	uint8_t flowtype = af == AF_INET ? FLOW_PING4 : FLOW_PING6;
> @@ -180,6 +184,7 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
>  	struct icmp_ping_flow *pingf;
>  	const struct flowside *tgt;
>  
> +	(void)qpair;
>  	if (!flow)
>  		return NULL;
>  
> @@ -234,6 +239,7 @@ cancel:
>  /**
>   * icmp_tap_handler() - Handle packets from tap
>   * @c:		Execution context
> + * @qpair:	Queue pair to process
>   * @pif:	pif on which the packet is arriving
>   * @af:		Address family, AF_INET or AF_INET6
>   * @saddr:	Source address
> @@ -243,8 +249,8 @@ cancel:
>   *
>   * Return: count of consumed packets (always 1, even if malformed)
>   */
> -int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
> -		     const void *saddr, const void *daddr,
> +int icmp_tap_handler(const struct ctx *c, unsigned int qpair, uint8_t pif,
> +		     sa_family_t af, const void *saddr, const void *daddr,
>  		     struct iov_tail *data, const struct timespec *now)
>  {
>  	struct iovec iov[MAX_IOV_ICMP];
> @@ -301,7 +307,7 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
>  
>  	if (flow)
>  		pingf = &flow->ping;
> -	else if (!(pingf = icmp_ping_new(c, af, id, saddr, daddr)))
> +	else if (!(pingf = icmp_ping_new(c, qpair, af, id, saddr, daddr)))
>  		return 1;
>  
>  	tgt = &pingf->f.side[TGTSIDE];
> diff --git a/icmp.h b/icmp.h
> index 556260461995..5cc067e57a9c 100644
> --- a/icmp.h
> +++ b/icmp.h
> @@ -13,9 +13,10 @@
>  struct ctx;
>  struct icmp_ping_flow;
>  
> -void icmp_sock_handler(const struct ctx *c, union epoll_ref ref);
> -int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
> -		     const void *saddr, const void *daddr,
> +void icmp_sock_handler(const struct ctx *c, union epoll_ref ref,
> +		       unsigned int qpair);
> +int icmp_tap_handler(const struct ctx *c, unsigned int qpair, uint8_t pif,
> +		     sa_family_t af, const void *saddr, const void *daddr,
>  		     struct iov_tail *data, const struct timespec *now);
>  void icmp_init(void);
>  
> diff --git a/passt.c b/passt.c
> index 41239991451f..c9e456641e85 100644
> --- a/passt.c
> +++ b/passt.c
> @@ -273,7 +273,7 @@ static void passt_worker(void *opaque, int nfds, struct epoll_event *events)
>  					 QPAIR_DEFAULT);
>  			break;
>  		case EPOLL_TYPE_PING:
> -			icmp_sock_handler(c, ref);
> +			icmp_sock_handler(c, ref, QPAIR_DEFAULT);
>  			break;
>  		case EPOLL_TYPE_VHOST_CMD:
>  			vu_control_handler(c->vdev, c->fd_tap, eventmask);
> diff --git a/tap.c b/tap.c
> index 8e19390f7273..de1e5269526c 100644
> --- a/tap.c
> +++ b/tap.c
> @@ -791,7 +791,7 @@ resume:
>  
>  			tap_packet_debug(iph, NULL, NULL, 0, NULL, 1);
>  
> -			icmp_tap_handler(c, PIF_TAP, AF_INET,
> +			icmp_tap_handler(c, qpair, PIF_TAP, AF_INET,
>  					 &iph->saddr, &iph->daddr,
>  					 &data, now);
>  			continue;
> @@ -1035,7 +1035,7 @@ resume:
>  
>  			tap_packet_debug(NULL, ip6h, NULL, proto, NULL, 1);
>  
> -			icmp_tap_handler(c, PIF_TAP, AF_INET6,
> +			icmp_tap_handler(c, qpair, PIF_TAP, AF_INET6,
>  					 saddr, daddr, &data, now);
>  			continue;
>  		}
> -- 
> 2.54.0
> 

-- 
David Gibson (he or they)	| 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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