From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by passt.top (Postfix) with ESMTP id 633E15A0268 for ; Thu, 17 Nov 2022 00:53:50 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668642829; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yQXq43reRqKnJ1JSpUj0Lvvz6IKGUYKmwe43ohUKrGM=; b=eKG4SqBR5mJRPvYdwK+mSD+Huqa8kRSZZjtfuhbmX8cpH2OROOLYu+WazI/X/aS+s5GSyy K56d/8L/J2233cuvkiC0XcdeRfhREX+RayZoU5KEFciZPwFcryWLR2V7x8fl515Bw6ifeR +FZuHS/LGvR348vf3YnTaLxZKBtrDuQ= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-413-t-yAjEMuPFWpvtiJBXFL4Q-1; Wed, 16 Nov 2022 18:53:46 -0500 X-MC-Unique: t-yAjEMuPFWpvtiJBXFL4Q-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CC00E29AB453; Wed, 16 Nov 2022 23:53:45 +0000 (UTC) Received: from maya.cloud.tilaa.com (ovpn-208-8.brq.redhat.com [10.40.208.8]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 97E39140EBF3; Wed, 16 Nov 2022 23:53:45 +0000 (UTC) Date: Thu, 17 Nov 2022 00:11:30 +0100 From: Stefano Brivio To: David Gibson Subject: Re: [PATCH 05/32] tcp: Better helpers for converting between connection pointer and index Message-ID: <20221117001130.247743ea@elisabeth> In-Reply-To: <20221116044212.3876516-6-david@gibson.dropbear.id.au> References: <20221116044212.3876516-1-david@gibson.dropbear.id.au> <20221116044212.3876516-6-david@gibson.dropbear.id.au> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: MAVRCOOR5DV6ZBLQXNY2SEOEVKE3ZLD7 X-Message-ID-Hash: MAVRCOOR5DV6ZBLQXNY2SEOEVKE3ZLD7 X-MailFrom: sbrivio@redhat.com 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: 3.3.3 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: On Wed, 16 Nov 2022 15:41:45 +1100 David Gibson wrote: > The macro CONN_OR_NULL() is used to look up connections by index with > bounds checking. Replace it with an inline function, which means: > - Better type checking > - No danger of multiple evaluation of an @index with side effects > > Also add a helper to perform the reverse translation: from connection > pointer to index. Introduce a macro for this which will make later > cleanups easier and safer. Ah, yes, much better, agreed. Just two things here: > Signed-off-by: David Gibson > --- > tcp.c | 83 ++++++++++++++++++++++++++++++++--------------------------- > 1 file changed, 45 insertions(+), 38 deletions(-) > > diff --git a/tcp.c b/tcp.c > index d043123..4e56a6c 100644 > --- a/tcp.c > +++ b/tcp.c > @@ -518,14 +518,6 @@ struct tcp_conn { > (conn->events & (SOCK_FIN_RCVD | TAP_FIN_RCVD))) > #define CONN_HAS(conn, set) ((conn->events & (set)) == (set)) > > -#define CONN(index) (tc + (index)) > - > -/* We probably don't want to use gcc statement expressions (for portability), so > - * use this only after well-defined sequence points (no pre-/post-increments). > - */ > -#define CONN_OR_NULL(index) \ > - (((int)(index) >= 0 && (index) < TCP_MAX_CONNS) ? (tc + (index)) : NULL) > - > static const char *tcp_event_str[] __attribute((__unused__)) = { > "SOCK_ACCEPTED", "TAP_SYN_RCVD", "ESTABLISHED", "TAP_SYN_ACK_SENT", > > @@ -705,6 +697,21 @@ static size_t tcp6_l2_flags_buf_bytes; > /* TCP connections */ > static struct tcp_conn tc[TCP_MAX_CONNS]; > > +#define CONN(index) (tc + (index)) > +#define CONN_IDX(conn) ((conn) - tc) > + > +/** conn_at_idx() - Find a connection by index, if present > + * @index: Index of connection to lookup > + * > + * Return: Pointer to connection, or NULL if @index is out of bounds Return: pointer [...] > + */ > +static inline struct tcp_conn *conn_at_idx(int index) The CONN_OR_NULL name made it very explicit that the pointer obtained there could be NULL. On the other hand I find conn_at_idx() more descriptive. But maybe conn_or_null() would be "safer". I don't really have a preference. -- Stefano