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Message-ID: <37d32749052f4ff887c5637671085389@AMSPEX02CL03.citrite.net>
Date: Thu, 22 Sep 2016 09:09:52 +0000
From: Paul Durrant <Paul.Durrant@...rix.com>
To: Juergen Gross <jgross@...e.com>,
"xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
"netdev@...r.kernel.orga" <netdev@...r.kernel.orga>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: Wei Liu <wei.liu2@...rix.com>
Subject: RE: [Xen-devel] [PATCH resend] xen-netback: switch to threaded irq
for control ring
> -----Original Message-----
> From: Xen-devel [mailto:xen-devel-bounces@...ts.xen.org] On Behalf Of
> Juergen Gross
> Sent: 22 September 2016 10:03
> To: xen-devel@...ts.xenproject.org; netdev@...r.kernel.orga; linux-
> kernel@...r.kernel.org
> Cc: Juergen Gross <jgross@...e.com>; Wei Liu <wei.liu2@...rix.com>
> Subject: [Xen-devel] [PATCH resend] xen-netback: switch to threaded irq for
> control ring
>
> Instead of open coding it use the threaded irq mechanism in xen-netback.
>
> Signed-off-by: Juergen Gross <jgross@...e.com>
How have you tested this change?
Paul
> ---
> resend due to missing netdev list in first attempt
> ---
> drivers/net/xen-netback/common.h | 4 +---
> drivers/net/xen-netback/interface.c | 38 ++++++-------------------------------
> drivers/net/xen-netback/netback.c | 18 ++++--------------
> 3 files changed, 11 insertions(+), 49 deletions(-)
>
> diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-
> netback/common.h
> index 84d6cbd..b38fb2c 100644
> --- a/drivers/net/xen-netback/common.h
> +++ b/drivers/net/xen-netback/common.h
> @@ -292,8 +292,6 @@ struct xenvif {
> #endif
>
> struct xen_netif_ctrl_back_ring ctrl;
> - struct task_struct *ctrl_task;
> - wait_queue_head_t ctrl_wq;
> unsigned int ctrl_irq;
>
> /* Miscellaneous private stuff. */
> @@ -359,7 +357,7 @@ void xenvif_kick_thread(struct xenvif_queue
> *queue);
>
> int xenvif_dealloc_kthread(void *data);
>
> -int xenvif_ctrl_kthread(void *data);
> +irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data);
>
> void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff
> *skb);
>
> diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-
> netback/interface.c
> index 83deeeb..fb50c6d 100644
> --- a/drivers/net/xen-netback/interface.c
> +++ b/drivers/net/xen-netback/interface.c
> @@ -128,15 +128,6 @@ irqreturn_t xenvif_interrupt(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> -irqreturn_t xenvif_ctrl_interrupt(int irq, void *dev_id) -{
> - struct xenvif *vif = dev_id;
> -
> - wake_up(&vif->ctrl_wq);
> -
> - return IRQ_HANDLED;
> -}
> -
> int xenvif_queue_stopped(struct xenvif_queue *queue) {
> struct net_device *dev = queue->vif->dev; @@ -570,8 +561,7 @@
> int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
> struct net_device *dev = vif->dev;
> void *addr;
> struct xen_netif_ctrl_sring *shared;
> - struct task_struct *task;
> - int err = -ENOMEM;
> + int err;
>
> err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
> &ring_ref, 1, &addr);
> @@ -581,11 +571,7 @@ int xenvif_connect_ctrl(struct xenvif *vif,
> grant_ref_t ring_ref,
> shared = (struct xen_netif_ctrl_sring *)addr;
> BACK_RING_INIT(&vif->ctrl, shared, XEN_PAGE_SIZE);
>
> - init_waitqueue_head(&vif->ctrl_wq);
> -
> - err = bind_interdomain_evtchn_to_irqhandler(vif->domid, evtchn,
> - xenvif_ctrl_interrupt,
> - 0, dev->name, vif);
> + err = bind_interdomain_evtchn_to_irq(vif->domid, evtchn);
> if (err < 0)
> goto err_unmap;
>
> @@ -593,19 +579,13 @@ int xenvif_connect_ctrl(struct xenvif *vif,
> grant_ref_t ring_ref,
>
> xenvif_init_hash(vif);
>
> - task = kthread_create(xenvif_ctrl_kthread, (void *)vif,
> - "%s-control", dev->name);
> - if (IS_ERR(task)) {
> - pr_warn("Could not allocate kthread for %s\n", dev->name);
> - err = PTR_ERR(task);
> + err = request_threaded_irq(vif->ctrl_irq, NULL, xenvif_ctrl_irq_fn,
> + IRQF_ONESHOT, "xen-netback-ctrl", vif);
> + if (err) {
> + pr_warn("Could not setup irq handler for %s\n", dev-
> >name);
> goto err_deinit;
> }
>
> - get_task_struct(task);
> - vif->ctrl_task = task;
> -
> - wake_up_process(vif->ctrl_task);
> -
> return 0;
>
> err_deinit:
> @@ -774,12 +754,6 @@ void xenvif_disconnect_data(struct xenvif *vif)
>
> void xenvif_disconnect_ctrl(struct xenvif *vif) {
> - if (vif->ctrl_task) {
> - kthread_stop(vif->ctrl_task);
> - put_task_struct(vif->ctrl_task);
> - vif->ctrl_task = NULL;
> - }
> -
> if (vif->ctrl_irq) {
> xenvif_deinit_hash(vif);
> unbind_from_irqhandler(vif->ctrl_irq, vif); diff --git
> a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> index edbae0b..3d0c989 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -2359,24 +2359,14 @@ static bool xenvif_ctrl_work_todo(struct xenvif
> *vif)
> return 0;
> }
>
> -int xenvif_ctrl_kthread(void *data)
> +irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
> {
> struct xenvif *vif = data;
>
> - for (;;) {
> - wait_event_interruptible(vif->ctrl_wq,
> - xenvif_ctrl_work_todo(vif) ||
> - kthread_should_stop());
> - if (kthread_should_stop())
> - break;
> + while (xenvif_ctrl_work_todo(vif))
> + xenvif_ctrl_action(vif);
>
> - while (xenvif_ctrl_work_todo(vif))
> - xenvif_ctrl_action(vif);
> -
> - cond_resched();
> - }
> -
> - return 0;
> + return IRQ_HANDLED;
> }
>
> static int __init netback_init(void)
> --
> 2.6.6
>
>
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> Xen-devel@...ts.xen.org
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