drm/i915: Clarify irq_lock locking, irq handlers

irq handlers always run with interrupts locally disabled, so
plain spinlocks is all we need. I've also reviewed again that they
all follow the _irq_handler postfix convention.
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -4063,7 +4063,6 @@ static irqreturn_t i8xx_irq_handler(int irq, void *arg)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u16 iir, new_iir;
 	u32 pipe_stats[2];
-	unsigned long irqflags;
 	int pipe;
 	u16 flip_mask =
 		I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
@@ -4079,7 +4078,7 @@ static irqreturn_t i8xx_irq_handler(int irq, void *arg)
 		 * It doesn't set the bit in iir again, but it still produces
 		 * interrupts (for non-MSI).
 		 */
-		spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+		spin_lock(&dev_priv->irq_lock);
 		if (iir & I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
 			i915_handle_error(dev, false,
 					  "Command parser error, iir 0x%08x",
@@ -4095,7 +4094,7 @@ static irqreturn_t i8xx_irq_handler(int irq, void *arg)
 			if (pipe_stats[pipe] & 0x8000ffff)
 				I915_WRITE(reg, pipe_stats[pipe]);
 		}
-		spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+		spin_unlock(&dev_priv->irq_lock);
 
 		I915_WRITE16(IIR, iir & ~flip_mask);
 		new_iir = I915_READ16(IIR); /* Flush posted writes */
@@ -4249,7 +4248,6 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 	struct drm_device *dev = arg;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 iir, new_iir, pipe_stats[I915_MAX_PIPES];
-	unsigned long irqflags;
 	u32 flip_mask =
 		I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
 		I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT;
@@ -4265,7 +4263,7 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 		 * It doesn't set the bit in iir again, but it still produces
 		 * interrupts (for non-MSI).
 		 */
-		spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+		spin_lock(&dev_priv->irq_lock);
 		if (iir & I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
 			i915_handle_error(dev, false,
 					  "Command parser error, iir 0x%08x",
@@ -4281,7 +4279,7 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 				irq_received = true;
 			}
 		}
-		spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+		spin_unlock(&dev_priv->irq_lock);
 
 		if (!irq_received)
 			break;
@@ -4476,7 +4474,6 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 iir, new_iir;
 	u32 pipe_stats[I915_MAX_PIPES];
-	unsigned long irqflags;
 	int ret = IRQ_NONE, pipe;
 	u32 flip_mask =
 		I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
@@ -4493,7 +4490,7 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 		 * It doesn't set the bit in iir again, but it still produces
 		 * interrupts (for non-MSI).
 		 */
-		spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+		spin_lock(&dev_priv->irq_lock);
 		if (iir & I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
 			i915_handle_error(dev, false,
 					  "Command parser error, iir 0x%08x",
@@ -4511,7 +4508,7 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 				irq_received = true;
 			}
 		}
-		spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+		spin_unlock(&dev_priv->irq_lock);
 
 		if (!irq_received)
 			break;