drm/i915: Protect PIPE_CONF_CHECK macros with do {} while(0)

Make the PIPE_CONF_CHECK macros a bit more robust by wrapping them
in do {} while(0). Avoids funky sirprises when you try put an 'else'
after a PIPE_CONF_CHECK invocation...

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180316183625.16316-1-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> #irc

drivers/gpu/drm/i915/intel_display.c

@@ -11141,39 +11141,42 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 		(current_config->base.mode.private_flags & I915_MODE_FLAG_INHERITED) &&
 		!(pipe_config->base.mode.private_flags & I915_MODE_FLAG_INHERITED);
 
-#define PIPE_CONF_CHECK_X(name)	\
+#define PIPE_CONF_CHECK_X(name) do { \
 	if (current_config->name != pipe_config->name) { \
 		pipe_config_err(adjust, __stringify(name), \
 			  "(expected 0x%08x, found 0x%08x)\n", \
 			  current_config->name, \
 			  pipe_config->name); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
-#define PIPE_CONF_CHECK_I(name)	\
+#define PIPE_CONF_CHECK_I(name) do { \
 	if (current_config->name != pipe_config->name) { \
 		pipe_config_err(adjust, __stringify(name), \
 			  "(expected %i, found %i)\n", \
 			  current_config->name, \
 			  pipe_config->name); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
-#define PIPE_CONF_CHECK_BOOL(name)	\
+#define PIPE_CONF_CHECK_BOOL(name) do { \
 	if (current_config->name != pipe_config->name) { \
 		pipe_config_err(adjust, __stringify(name), \
 			  "(expected %s, found %s)\n", \
 			  yesno(current_config->name), \
 			  yesno(pipe_config->name)); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
 /*
  * Checks state where we only read out the enabling, but not the entire
  * state itself (like full infoframes or ELD for audio). These states
  * require a full modeset on bootup to fix up.
  */
-#define PIPE_CONF_CHECK_BOOL_INCOMPLETE(name) \
+#define PIPE_CONF_CHECK_BOOL_INCOMPLETE(name) do { \
 	if (!fixup_inherited || (!current_config->name && !pipe_config->name)) { \
 		PIPE_CONF_CHECK_BOOL(name); \
 	} else { \
@@ -11182,18 +11185,20 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 			  yesno(current_config->name), \
 			  yesno(pipe_config->name)); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
-#define PIPE_CONF_CHECK_P(name)	\
+#define PIPE_CONF_CHECK_P(name) do { \
 	if (current_config->name != pipe_config->name) { \
 		pipe_config_err(adjust, __stringify(name), \
 			  "(expected %p, found %p)\n", \
 			  current_config->name, \
 			  pipe_config->name); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
-#define PIPE_CONF_CHECK_M_N(name) \
+#define PIPE_CONF_CHECK_M_N(name) do { \
 	if (!intel_compare_link_m_n(&current_config->name, \
 				    &pipe_config->name,\
 				    adjust)) { \
@@ -11211,14 +11216,15 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 			  pipe_config->name.link_m, \
 			  pipe_config->name.link_n); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
 /* This is required for BDW+ where there is only one set of registers for
  * switching between high and low RR.
  * This macro can be used whenever a comparison has to be made between one
  * hw state and multiple sw state variables.
  */
-#define PIPE_CONF_CHECK_M_N_ALT(name, alt_name) \
+#define PIPE_CONF_CHECK_M_N_ALT(name, alt_name) do { \
 	if (!intel_compare_link_m_n(&current_config->name, \
 				    &pipe_config->name, adjust) && \
 	    !intel_compare_link_m_n(&current_config->alt_name, \
@@ -11243,9 +11249,10 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 			  pipe_config->name.link_m, \
 			  pipe_config->name.link_n); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
-#define PIPE_CONF_CHECK_FLAGS(name, mask)	\
+#define PIPE_CONF_CHECK_FLAGS(name, mask) do { \
 	if ((current_config->name ^ pipe_config->name) & (mask)) { \
 		pipe_config_err(adjust, __stringify(name), \
 			  "(%x) (expected %i, found %i)\n", \
@@ -11253,16 +11260,18 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 			  current_config->name & (mask), \
 			  pipe_config->name & (mask)); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
-#define PIPE_CONF_CHECK_CLOCK_FUZZY(name) \
+#define PIPE_CONF_CHECK_CLOCK_FUZZY(name) do { \
 	if (!intel_fuzzy_clock_check(current_config->name, pipe_config->name)) { \
 		pipe_config_err(adjust, __stringify(name), \
 			  "(expected %i, found %i)\n", \
 			  current_config->name, \
 			  pipe_config->name); \
 		ret = false; \
-	}
+	} \
+} while (0)
 
 #define PIPE_CONF_QUIRK(quirk)	\
 	((current_config->quirks | pipe_config->quirks) & (quirk))