From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=202512 header.b=dBTszni2; dkim-atps=neutral Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id B46155A0624 for ; Tue, 20 Jan 2026 01:09:37 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202512; t=1768867773; bh=WcEkUO/fciqO5rBZm/7TTVgUsvd+bOEdQCtnO9k1WdQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dBTszni2IG3cxfhqrc3L4UG9V0hBZzf5PkcP748UAeqfg7hdxM0qLncsoRKKAYRgD dfaQD5Fwi6hz0mQcjXVFN3HsJtAsnxeOWApiHFJaTC2nYiBAj8/Qcbmspc3McTbrjJ X4MQlvZwJuQgloEhKWYhb54C2S/OEaCkTqk+Yn8iPZ42R2+tmNfQrcv4TNtsmsPkRO ymnKmS82WIfUI3nq0Ze1y/Zp4KYGTHcoslLYiFbWLfja5K7WlMeZFt++TsWiMWVaK0 S30+ciX9HteVbkK+m3nWfhi+3zav2vtRQwA/xQKugfKeb6VtaBRyQ17Hsfk5CKGff0 crWyzmVQYx06w== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4dw73x4GYnz4wCm; Tue, 20 Jan 2026 11:09:33 +1100 (AEDT) Date: Tue, 20 Jan 2026 11:08:30 +1100 From: David Gibson To: Laurent Vivier Subject: Re: [PATCH v2 2/3] tcp: Register fds with epoll at flow creation Message-ID: References: <20260119161915.4014677-1-lvivier@redhat.com> <20260119161915.4014677-3-lvivier@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="nF0lvV79F13b0LAv" Content-Disposition: inline In-Reply-To: <20260119161915.4014677-3-lvivier@redhat.com> Message-ID-Hash: M6F45NMJTWBDIGE3AK7JPJK64O2GLJDD X-Message-ID-Hash: M6F45NMJTWBDIGE3AK7JPJK64O2GLJDD X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --nF0lvV79F13b0LAv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jan 19, 2026 at 05:19:14PM +0100, Laurent Vivier wrote: > Register connection sockets with epoll using empty events > (events=3D0) in tcp_conn_from_tap(), tcp_tap_conn_from_sock() > and tcp_flow_repair_socket(). >=20 > This allows tcp_epoll_ctl() to always use EPOLL_CTL_MOD, removing > the need to check whether fds are already registered. As a result, the > conditional ADD/MOD logic is no longer needed, simplifying the function. >=20 > Signed-off-by: Laurent Vivier Reviewed-by: David Gibson > --- > flow.c | 1 + > tcp.c | 46 ++++++++++++++++++++++++---------------------- > 2 files changed, 25 insertions(+), 22 deletions(-) >=20 > diff --git a/flow.c b/flow.c > index cefe6c8b5b24..532339ce7fe1 100644 > --- a/flow.c > +++ b/flow.c > @@ -357,6 +357,7 @@ static void flow_set_state(struct flow_common *f, enu= m flow_state state) > * > * Return: true if flow is registered with epoll, false otherwise > */ > +/* cppcheck-suppress unusedFunction */ > bool flow_in_epoll(const struct flow_common *f) > { > return f->epollid !=3D EPOLLFD_ID_INVALID; > diff --git a/tcp.c b/tcp.c > index 1db861705ddb..29d69354bd94 100644 > --- a/tcp.c > +++ b/tcp.c > @@ -528,37 +528,22 @@ static uint32_t tcp_conn_epoll_events(uint8_t event= s, uint8_t conn_flags) > static int tcp_epoll_ctl(struct tcp_tap_conn *conn) > { > uint32_t events; > - int m; > =20 > if (conn->events =3D=3D CLOSED) { > - if (flow_in_epoll(&conn->f)) { > - int epollfd =3D flow_epollfd(&conn->f); > + int epollfd =3D flow_epollfd(&conn->f); > =20 > - epoll_del(epollfd, conn->sock); > - if (conn->timer !=3D -1) > - epoll_del(epollfd, conn->timer); > - } > + epoll_del(epollfd, conn->sock); > + if (conn->timer !=3D -1) > + epoll_del(epollfd, conn->timer); > =20 > return 0; > } > =20 > events =3D tcp_conn_epoll_events(conn->events, conn->flags); > =20 > - if (flow_in_epoll(&conn->f)) { > - m =3D EPOLL_CTL_MOD; > - } else { > - flow_epollid_set(&conn->f, EPOLLFD_ID_DEFAULT); > - m =3D EPOLL_CTL_ADD; > - } > - > - if (flow_epoll_set(&conn->f, m, events, conn->sock, > - !TAPSIDE(conn)) < 0) { > - int ret =3D -errno; > - > - if (m =3D=3D EPOLL_CTL_ADD) > - flow_epollid_clear(&conn->f); > - return ret; > - } > + if (flow_epoll_set(&conn->f, EPOLL_CTL_MOD, events, conn->sock, > + !TAPSIDE(conn)) < 0) > + return -errno; > =20 > return 0; > } > @@ -1710,6 +1695,11 @@ static void tcp_conn_from_tap(const struct ctx *c,= sa_family_t af, > conn->sock =3D s; > conn->timer =3D -1; > conn->listening_sock =3D -1; > + flow_epollid_set(&conn->f, EPOLLFD_ID_DEFAULT); > + if (flow_epoll_set(&conn->f, EPOLL_CTL_ADD, 0, s, TGTSIDE) < 0) { > + flow_perror(flow, "Can't register with epoll"); > + goto cancel; > + } > conn_event(c, conn, TAP_SYN_RCVD); > =20 > conn->wnd_to_tap =3D WINDOW_DEFAULT; > @@ -2433,6 +2423,15 @@ static void tcp_tap_conn_from_sock(const struct ct= x *c, union flow *flow, > conn->sock =3D s; > conn->timer =3D -1; > conn->ws_to_tap =3D conn->ws_from_tap =3D 0; > + > + flow_epollid_set(&conn->f, EPOLLFD_ID_DEFAULT); > + if (flow_epoll_set(&conn->f, EPOLL_CTL_ADD, 0, s, INISIDE) < 0) { > + flow_perror(flow, "Can't register with epoll"); > + conn_flag(c, conn, CLOSING); > + FLOW_ACTIVATE(conn); > + return; > + } > + > conn_event(c, conn, SOCK_ACCEPTED); > =20 > hash =3D flow_hash_insert(c, TAP_SIDX(conn)); > @@ -3825,6 +3824,9 @@ int tcp_flow_migrate_target(struct ctx *c, int fd) > return 0; > } > =20 > + flow_epollid_set(&conn->f, EPOLLFD_ID_DEFAULT); > + flow_epoll_set(&conn->f, EPOLL_CTL_ADD, 0, conn->sock, !TAPSIDE(conn)); > + > flow_hash_insert(c, TAP_SIDX(conn)); > FLOW_ACTIVATE(conn); > =20 > --=20 > 2.52.0 >=20 --=20 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 --nF0lvV79F13b0LAv Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEO+dNsU4E3yXUXRK2zQJF27ox2GcFAmlux30ACgkQzQJF27ox 2Gfi2hAAomYLIGHSTm2tQrxcC2k0G0VPKQKGo/MtlwQS0+HBQRiKsLbUcAg6UFQx QLMEOSyjHE6+wqVHMs4snyoE8Iq6ZP8YsiUYZuCYG2q+LIobUSQNcw95CVB6zz27 UIEZLZO9m4jSpA8wMdkoat30rh6nAbsiLpACje/rFjNNa8GifJrbcRH8qju7ee7y 4Fkj+WzackubfcHjEWCtxmSeyrjIQS2W/So22/jyd6CNFHwve1niEeLcpAnqC/X9 4KUsrzClij3tm0O5PGa6pOEc5hHIcbGETVrouLwATjoKWICoYEFa5Z9ZggHbdL8s QZGSkZGUFv2GRyt2yNMujo3sMYthLKXejXPZuHWcJCnnK2FpTWzErwk5M4yKpax4 MoxPhtiZjOrHbU9ektFEN+8PjvwqNAOWedMUfs2z+ucCw+DhjhjELPSYEhaJjPLz IF7aZBmjx/N5Hd8SEMx+1A8CrhuvrnvEUahVec7OApNeJQvMpCCXCqVRoQqfOxcf F8ALrnlssFvNYo4etS5W6s8kiH+LQAhLOf8UpmL1zJ1tyVrfeGWnjorFVKebYMVy 0SC3yV38JYCpt2L5zO3D8I9mKTkIk5vPMo4Na3VFGed3ZwZcmE/UbsrlTKYXKaFQ +0Xyyf0k6cHerIfCihVrNiFNJiyp2GCXRPX/rRzpwOB7Kwb8niA= =xZ6v -----END PGP SIGNATURE----- --nF0lvV79F13b0LAv--