Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754056AbdFNBAU (ORCPT ); Tue, 13 Jun 2017 21:00:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:33694 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753813AbdFNBAT (ORCPT ); Tue, 13 Jun 2017 21:00:19 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CBDB822CB7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=sstabellini@kernel.org Date: Tue, 13 Jun 2017 18:00:17 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@sstabellini-ThinkPad-X260 To: Juergen Gross cc: Stefano Stabellini , xen-devel@lists.xen.org, linux-kernel@vger.kernel.org, boris.ostrovsky@oracle.com, Stefano Stabellini Subject: Re: [PATCH v3 17/18] xen/pvcalls: implement write In-Reply-To: Message-ID: References: <1496431915-20774-1-git-send-email-sstabellini@kernel.org> <1496431915-20774-17-git-send-email-sstabellini@kernel.org> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3803 Lines: 120 On Tue, 13 Jun 2017, Juergen Gross wrote: > On 02/06/17 21:31, Stefano Stabellini wrote: > > When the other end notifies us that there is data to be written > > (pvcalls_back_conn_event), increment the io and write counters, and > > schedule the ioworker. > > > > Implement the write function called by ioworker by reading the data from > > the data ring, writing it to the socket by calling inet_sendmsg. > > > > Set out_error on error. > > > > Signed-off-by: Stefano Stabellini > > CC: boris.ostrovsky@oracle.com > > CC: jgross@suse.com > > --- > > drivers/xen/pvcalls-back.c | 74 +++++++++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 73 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c > > index e7d2b85..fe3e70f 100644 > > --- a/drivers/xen/pvcalls-back.c > > +++ b/drivers/xen/pvcalls-back.c > > @@ -180,7 +180,66 @@ static void pvcalls_conn_back_read(unsigned long opaque) > > > > static int pvcalls_conn_back_write(struct sock_mapping *map) > > { > > - return 0; > > + struct pvcalls_data_intf *intf = map->ring; > > + struct pvcalls_data *data = &map->data; > > + struct msghdr msg; > > + struct kvec vec[2]; > > + RING_IDX cons, prod, size, ring_size; > > + int ret; > > + > > + cons = intf->out_cons; > > + prod = intf->out_prod; > > + /* read the indexes before dealing with the data */ > > + virt_mb(); > > + > > + ring_size = XEN_FLEX_RING_SIZE(map->ring_order); > > + size = pvcalls_queued(prod, cons, ring_size); > > + if (size == 0) > > + return 0; > > + > > + memset(&msg, 0, sizeof(msg)); > > + msg.msg_flags |= MSG_DONTWAIT; > > + msg.msg_iter.type = ITER_KVEC|READ; > > + msg.msg_iter.count = size; > > + if (pvcalls_mask(prod, ring_size) > pvcalls_mask(cons, ring_size)) { > > + vec[0].iov_base = data->out + pvcalls_mask(cons, ring_size); > > + vec[0].iov_len = size; > > + msg.msg_iter.kvec = vec; > > + msg.msg_iter.nr_segs = 1; > > + } else { > > + vec[0].iov_base = data->out + pvcalls_mask(cons, ring_size); > > + vec[0].iov_len = ring_size - pvcalls_mask(cons, ring_size); > > + vec[1].iov_base = data->out; > > + vec[1].iov_len = size - vec[0].iov_len; > > + msg.msg_iter.kvec = vec; > > + msg.msg_iter.nr_segs = 2; > > + } > > + > > + atomic_set(&map->write, 0); > > + ret = inet_sendmsg(map->sock, &msg, size); > > + if (ret == -EAGAIN || ret < size) { > > Do you really want to do this for all errors? > Or did you mean: > if ((ret >= 0 && ret < size) || ret == -EAGAIN) Yes, that's what I meant, thanks! > > + atomic_inc(&map->write); > > + atomic_inc(&map->io); > > + } > > + if (ret == -EAGAIN) > > + return ret; > > + > > + /* write the data, then update the indexes */ > > + virt_wmb(); > > + if (ret < 0) { > > + intf->out_error = ret; > > + } else { > > + intf->out_error = 0; > > + intf->out_cons = cons + ret; > > + prod = intf->out_prod; > > + } > > + /* update the indexes, then notify the other end */ > > + virt_wmb(); > > + if (prod != cons + ret) > > + atomic_inc(&map->write); > > + notify_remote_via_irq(map->irq); > > + > > + return ret; > > } > > > > static void pvcalls_back_ioworker(struct work_struct *work) > > @@ -837,6 +896,19 @@ static irqreturn_t pvcalls_back_event(int irq, void *dev_id) > > > > static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map) > > { > > + struct sock_mapping *map = sock_map; > > + struct pvcalls_ioworker *iow; > > + > > + if (map == NULL || map->sock == NULL || map->sock->sk == NULL || > > + map->sock->sk->sk_user_data != map) > > + return IRQ_HANDLED; > > + > > + iow = &map->ioworker; > > + > > + atomic_inc(&map->write); > > + atomic_inc(&map->io); > > + queue_work_on(iow->cpu, iow->wq, &iow->register_work); > > + > > return IRQ_HANDLED; > > } > > > > >