drm/i915: Add might_sleep() check to wait_for()

We should long past the time of trying to use wait_for() from inside
atomic contexts, so add a might_sleep() check to prevent misuse.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171114215655.4849-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index e9b66e0..645c5e8 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -47,14 +47,11 @@
  * contexts. Note that it's important that we check the condition again after
  * having timed out, since the timeout could be due to preemption or similar and
  * we've never had a chance to check the condition before the timeout.
- *
- * TODO: When modesetting has fully transitioned to atomic, the below
- * drm_can_sleep() can be removed and in_atomic()/!in_atomic() asserts
- * added.
  */
 #define _wait_for(COND, US, W) ({ \
        unsigned long timeout__ = jiffies + usecs_to_jiffies(US) + 1;   \
        int ret__;                                                      \
+       might_sleep();                                                  \
        for (;;) {                                                      \
                bool expired__ = time_after(jiffies, timeout__);        \
                if (COND) {                                             \
@@ -65,11 +62,7 @@
                        ret__ = -ETIMEDOUT;                             \
                        break;                                          \
                }                                                       \
-               if ((W) && drm_can_sleep()) {                           \
-                       usleep_range((W), (W)*2);                       \
-               } else {                                                \
-                       cpu_relax();                                    \
-               }                                                       \
+               usleep_range((W), (W) * 2);                             \
        }                                                               \
        ret__;                                                          \
 })