drm/i915: Stop needlessly acquiring wakeref for debugfs/drop_caches_set

We only need to acquire a wakeref for ourselves for a few operations, as
most either already acquire their own wakeref or imply a wakeref. In
particular, it is i915_gem_set_wedged() that needed us to present it
with a wakeref, which is incongruous with its "use anywhere" ability.

Suggested-by: "Yokoyama, Caz" <caz.yokoyama@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: "Yokoyama, Caz" <caz.yokoyama@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190318095204.9913-7-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 6a90558..08683dc 100644 (file)
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -3888,12 +3888,9 @@ static int
 i915_drop_caches_set(void *data, u64 val)
 {
        struct drm_i915_private *i915 = data;
-       intel_wakeref_t wakeref;
-       int ret = 0;
 
        DRM_DEBUG("Dropping caches: 0x%08llx [0x%08llx]\n",
                  val, val & DROP_ALL);
-       wakeref = intel_runtime_pm_get(i915);
 
        if (val & DROP_RESET_ACTIVE &&
            wait_for(intel_engines_are_idle(i915), I915_IDLE_ENGINES_TIMEOUT))
@@ -3902,9 +3899,11 @@ i915_drop_caches_set(void *data, u64 val)
        /* No need to check and wait for gpu resets, only libdrm auto-restarts
         * on ioctls on -EAGAIN. */
        if (val & (DROP_ACTIVE | DROP_RETIRE | DROP_RESET_SEQNO)) {
+               int ret;
+
                ret = mutex_lock_interruptible(&i915->drm.struct_mutex);
                if (ret)
-                       goto out;
+                       return ret;
 
                if (val & DROP_ACTIVE)
                        ret = i915_gem_wait_for_idle(i915,
@@ -3943,10 +3942,7 @@ i915_drop_caches_set(void *data, u64 val)
        if (val & DROP_FREED)
                i915_gem_drain_freed_objects(i915);
 
-out:
-       intel_runtime_pm_put(i915, wakeref);
-
-       return ret;
+       return 0;
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(i915_drop_caches_fops,

diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c
index 861fe08..fb86d5c 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reset.c
+++ b/drivers/gpu/drm/i915/i915_reset.c
@@ -863,9 +863,11 @@ static void __i915_gem_set_wedged(struct drm_i915_private *i915)
 void i915_gem_set_wedged(struct drm_i915_private *i915)
 {
        struct i915_gpu_error *error = &i915->gpu_error;
+       intel_wakeref_t wakeref;
 
        mutex_lock(&error->wedge_mutex);
-       __i915_gem_set_wedged(i915);
+       with_intel_runtime_pm(i915, wakeref)
+               __i915_gem_set_wedged(i915);
        mutex_unlock(&error->wedge_mutex);
 }