Mailing List Archive

Some lock wants to be held to make sure the port doesn't change state,
but there's no point holding the per-domain event lock here. Switch to
using the finer grained per-channel lock instead.

FAOD this doesn't guarantee anything towards in particular
evtchn_fifo_set_pending(), as for interdomain channels that function
would be called with the remote side's per-channel lock held.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: Drop acquiring of event lock. Re-write title and description.

--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -1154,20 +1154,17 @@ static long evtchn_set_priority(const st
{
struct domain *d = current->domain;
unsigned int port = set_priority->port;
+ struct evtchn *chn;
long ret;
-
- spin_lock(&d->event_lock);
+ unsigned long flags;

if ( !port_is_valid(d, port) )
- {
- spin_unlock(&d->event_lock);
return -EINVAL;
- }
-
- ret = evtchn_port_set_priority(d, evtchn_from_port(d, port),
- set_priority->priority);

- spin_unlock(&d->event_lock);
+ chn = evtchn_from_port(d, port);
+ spin_lock_irqsave(&chn->lock, flags);
+ ret = evtchn_port_set_priority(d, chn, set_priority->priority);
+ spin_unlock_irqrestore(&chn->lock, flags);

return ret;
}