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Tue, 14 Jun 2022 08:38:24 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.137]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D0FFA416164; Tue, 14 Jun 2022 08:38:23 +0000 (UTC) Date: Tue, 14 Jun 2022 09:38:21 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Leonardo Bras Cc: Peter Xu , =?utf-8?B?5b6Q6Zev?= , David Gilbert , Juan Quintela , qemu-devel@nongnu.org Subject: Re: [PATCH v3 1/2] QIOChannelSocket: Introduce assert and reduce ifdefs to improve readability Message-ID: References: <20220614051725.143985-1-leobras@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220614051725.143985-1-leobras@redhat.com> User-Agent: Mutt/2.2.1 (2022-02-19) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Jun 14, 2022 at 02:17:25AM -0300, Leonardo Bras wrote: > During implementation of MSG_ZEROCOPY feature, a lot of #ifdefs were > introduced, particularly at qio_channel_socket_writev(). > > Rewrite some of those changes so it's easier to read. > > Also, introduce an assert to help detect incorrect zero-copy usage is when > it's disabled on build. > > Signed-off-by: Leonardo Bras > --- > io/channel-socket.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/io/channel-socket.c b/io/channel-socket.c > index dc9c165de1..cdce7b0b45 100644 > --- a/io/channel-socket.c > +++ b/io/channel-socket.c > @@ -578,11 +578,13 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, > memcpy(CMSG_DATA(cmsg), fds, fdsize); > } > > -#ifdef QEMU_MSG_ZEROCOPY > if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) { > +#ifdef QEMU_MSG_ZEROCOPY > sflags = MSG_ZEROCOPY; > - } > +#else I would just add a comment: /* We expect QIOChannel class entry point to have blocked this code path already */ > + g_assert_unreachable(); > #endif > + } > > retry: > ret = sendmsg(sioc->fd, &msg, sflags); > @@ -592,15 +594,13 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, > return QIO_CHANNEL_ERR_BLOCK; > case EINTR: > goto retry; > -#ifdef QEMU_MSG_ZEROCOPY > case ENOBUFS: > - if (sflags & MSG_ZEROCOPY) { > + if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) { > error_setg_errno(errp, errno, > "Process can't lock enough memory for using MSG_ZEROCOPY"); > return -1; > } > break; > -#endif > } > > error_setg_errno(errp, errno, Reviewed-by: Daniel P. Berrangé With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|