drm/i915: Split breadcrumbs spinlock into two
As we now take the breadcrumbs spinlock within the interrupt handler, we
wish to minimise its hold time. During the interrupt we do not care
about the state of the full rbtree, only that of the first element, so
we can guard that with a separate lock.
v2: Rename first_wait to irq_wait to make it clearer that it is guarded
by irq_lock.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170303190824.1330-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 059335f..9505011 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -4097,16 +4097,16 @@ __i915_request_irq_complete(const struct drm_i915_gem_request *req)
* the seqno before we believe it coherent since they see
* irq_posted == false but we are still running).
*/
- spin_lock_irqsave(&b->lock, flags);
- if (b->first_wait && b->first_wait->tsk != current)
+ spin_lock_irqsave(&b->irq_lock, flags);
+ if (b->irq_wait && b->irq_wait->tsk != current)
/* Note that if the bottom-half is changed as we
* are sending the wake-up, the new bottom-half will
* be woken by whomever made the change. We only have
* to worry about when we steal the irq-posted for
* ourself.
*/
- wake_up_process(b->first_wait->tsk);
- spin_unlock_irqrestore(&b->lock, flags);
+ wake_up_process(b->irq_wait->tsk);
+ spin_unlock_irqrestore(&b->irq_lock, flags);
if (__i915_gem_request_completed(req, seqno))
return true;