__i915_spin_request() sucks

[Jens Axboe]

Previous patch was obvious pre-coffee crap, this should work for using
ktime to spin max 1usec.

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 5cf4a1998273..21192e55c33c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1148,17 +1148,18 @@ static bool missed_irq(struct drm_i915_private 
*dev_priv,

 static int __i915_spin_request(struct drm_i915_gem_request *req)
 {
-       unsigned long timeout;
+       ktime_t timeout;

        if (i915_gem_request_get_ring(req)->irq_refcount)
                return -EBUSY;

-       timeout = jiffies + 1;
+       timeout = ktime_get();
+       ktime_add_us(timeout, 1);
        while (!need_resched()) {
                if (i915_gem_request_completed(req, true))
                        return 0;

-               if (time_after_eq(jiffies, timeout))
+               if (ktime_after(ktime_get(), timeout))
                        break;

                cpu_relax_lowlatency();

-- 
Jens Axboe