| Message ID | 20201022074214.21693-5-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen: event handling cleanup | expand |
On 22.10.2020 09:42, Juergen Gross wrote: > --- a/drivers/xen/events/events_fifo.c > +++ b/drivers/xen/events/events_fifo.c > @@ -236,6 +236,9 @@ static bool clear_masked_cond(volatile event_word_t *word) > > w = *word; > > + if (!(w & (1 << EVTCHN_FIFO_MASKED))) > + return true; Maybe better move this ... > do { > if (w & (1 << EVTCHN_FIFO_PENDING)) > return false; > ... into the loop, above this check? Jan
On 22.10.20 09:55, Jan Beulich wrote: > On 22.10.2020 09:42, Juergen Gross wrote: >> --- a/drivers/xen/events/events_fifo.c >> +++ b/drivers/xen/events/events_fifo.c >> @@ -236,6 +236,9 @@ static bool clear_masked_cond(volatile event_word_t *word) >> >> w = *word; >> >> + if (!(w & (1 << EVTCHN_FIFO_MASKED))) >> + return true; > > Maybe better move this ... > >> do { >> if (w & (1 << EVTCHN_FIFO_PENDING)) >> return false; >> > > ... into the loop, above this check? Yes, that should be better. Juergen
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c index 243e7b6d7b96..f60c5a9ec833 100644 --- a/drivers/xen/events/events_fifo.c +++ b/drivers/xen/events/events_fifo.c @@ -236,6 +236,9 @@ static bool clear_masked_cond(volatile event_word_t *word) w = *word; + if (!(w & (1 << EVTCHN_FIFO_MASKED))) + return true; + do { if (w & (1 << EVTCHN_FIFO_PENDING)) return false;
Unmasking an event channel with fifo events channels being used can require a hypercall to be made, so try to avoid that by checking whether the event channel was really masked. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> --- drivers/xen/events/events_fifo.c | 3 +++ 1 file changed, 3 insertions(+)