[PATCH v2 6/8] drm/i915: Use an atomic_t array to track power domain use count.

[Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>]

Convert the power_domains->domain_use_count array that tracks per-domain
use count to atomic_t type. This is needed to be able to read/write the use
counts outside of the power domain mutex.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c     |  2 +-
 drivers/gpu/drm/i915/i915_drv.h         |  2 +-
 drivers/gpu/drm/i915/intel_runtime_pm.c | 11 +++++------
 3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 1a7b28f62570..1f1d9162f2c2 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2764,7 +2764,7 @@ static int i915_power_domain_info(struct seq_file *m, void *unused)
 		for_each_power_domain(power_domain, power_well->domains)
 			seq_printf(m, "  %-23s %d\n",
 				 intel_display_power_domain_str(power_domain),
-				 power_domains->domain_use_count[power_domain]);
+				 atomic_read(&power_domains->domain_use_count[power_domain]));
 	}
 
 	mutex_unlock(&power_domains->lock);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1e4e613e7b41..ddadeb9eaf49 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1489,7 +1489,7 @@ struct i915_power_domains {
 	int power_well_count;
 
 	struct mutex lock;
-	int domain_use_count[POWER_DOMAIN_NUM];
+	atomic_t domain_use_count[POWER_DOMAIN_NUM];
 	struct i915_power_well *power_wells;
 };
 
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 96ab74f3d101..992caec1fbc4 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -1453,7 +1453,7 @@ __intel_display_power_get_domain(struct drm_i915_private *dev_priv,
 	for_each_power_domain_well(dev_priv, power_well, BIT_ULL(domain))
 		intel_power_well_get(dev_priv, power_well);
 
-	power_domains->domain_use_count[domain]++;
+	atomic_inc(&power_domains->domain_use_count[domain]);
 }
 
 /**
@@ -1539,10 +1539,9 @@ void intel_display_power_put(struct drm_i915_private *dev_priv,
 
 	mutex_lock(&power_domains->lock);
 
-	WARN(!power_domains->domain_use_count[domain],
-	     "Use count on domain %s is already zero\n",
+	WARN(atomic_dec_return(&power_domains->domain_use_count[domain]) < 0,
+	     "Use count on domain %s was already zero\n",
 	     intel_display_power_domain_str(domain));
-	power_domains->domain_use_count[domain]--;
 
 	for_each_power_domain_well_rev(dev_priv, power_well, BIT_ULL(domain))
 		intel_power_well_put(dev_priv, power_well);
@@ -3049,7 +3048,7 @@ static void intel_power_domains_dump_info(struct drm_i915_private *dev_priv)
 		for_each_power_domain(domain, power_well->domains)
 			DRM_DEBUG_DRIVER("  %-23s %d\n",
 					 intel_display_power_domain_str(domain),
-					 power_domains->domain_use_count[domain]);
+					 atomic_read(&power_domains->domain_use_count[domain]));
 	}
 }
 
@@ -3092,7 +3091,7 @@ void intel_power_domains_verify_state(struct drm_i915_private *dev_priv)
 
 		domains_count = 0;
 		for_each_power_domain(domain, power_well->domains)
-			domains_count += power_domains->domain_use_count[domain];
+			domains_count += atomic_read(&power_domains->domain_use_count[domain]);
 
 		if (power_well->count != domains_count) {
 			DRM_ERROR("power well %s refcount/domain refcount mismatch "
-- 
2.11.0

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