Re: [PATCH 4/9] drm/xen-front: Implement Xen event channel handling

From: Oleksandr Andrushchenko
Date: Fri Feb 23 2018 - 09:49:55 EST


On 02/23/2018 04:44 PM, Boris Ostrovsky wrote:
On 02/23/2018 02:00 AM, Oleksandr Andrushchenko wrote:
On 02/23/2018 01:50 AM, Boris Ostrovsky wrote:
On 02/21/2018 03:03 AM, Oleksandr Andrushchenko wrote:
+
+static irqreturn_t evtchnl_interrupt_ctrl(int irq, void *dev_id)
+{
+ struct xen_drm_front_evtchnl *evtchnl = dev_id;
+ struct xen_drm_front_info *front_info = evtchnl->front_info;
+ struct xendispl_resp *resp;
+ RING_IDX i, rp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&front_info->io_lock, flags);
+
+ if (unlikely(evtchnl->state != EVTCHNL_STATE_CONNECTED))
+ goto out;
Do you need to check the state under lock? (in other routines too).
not really, will move out of the lock in interrupt handlers
other places (I assume you refer to be_stream_do_io)

I was mostly referring to evtchnl_interrupt_evt().
ah, then we are on the same page: I will move the check
in interrupt handlers
-boris


it is set under lock as a part of atomic operation, e.g.
we get a new request pointer from the ring and reset completion
So, those places still seem to be ok