drm: drm_err: Remove unnecessary __func__ argument

Removing the unnecessary drm_err __func__ argument by using
the equivalent %pf and __builtin_return_address(0) makes the
code smaller for every use of the DRM_ERROR macro.

For instance: (allmodconfig)

$ size drivers/gpu/drm/i915/i915.o*
   text	   data	    bss	    dec	    hex	filename
 922447	 193257	 296736	1412440	 158d58	drivers/gpu/drm/i915/i915.o.new
 928111	 193257	 296736	1418104	 15a378	drivers/gpu/drm/i915/i915.o.old
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_drv.c

@@ -56,7 +56,7 @@ static struct idr drm_minors_idr;
 struct class *drm_class;
 static struct dentry *drm_debugfs_root;
 
-void drm_err(const char *func, const char *format, ...)
+void drm_err(const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;
@@ -66,7 +66,8 @@ void drm_err(const char *func, const char *format, ...)
 	vaf.fmt = format;
 	vaf.va = &args;
 
-	printk(KERN_ERR "[" DRM_NAME ":%s] *ERROR* %pV", func, &vaf);
+	printk(KERN_ERR "[" DRM_NAME ":%pf] *ERROR* %pV",
+	       __builtin_return_address(0), &vaf);
 
 	va_end(args);
 }

include/drm/drmP.h

@@ -125,8 +125,8 @@ struct dma_buf_attachment;
 extern __printf(2, 3)
 void drm_ut_debug_printk(const char *function_name,
 			 const char *format, ...);
-extern __printf(2, 3)
-void drm_err(const char *func, const char *format, ...);
+extern __printf(1, 2)
+void drm_err(const char *format, ...);
 
 /***********************************************************************/
 /** \name DRM template customization defaults */
@@ -155,7 +155,7 @@ void drm_err(const char *func, const char *format, ...);
  * \param arg arguments
  */
 #define DRM_ERROR(fmt, ...)				\
-	drm_err(__func__, fmt, ##__VA_ARGS__)
+	drm_err(fmt, ##__VA_ARGS__)
 
 /**
  * Rate limited error output.  Like DRM_ERROR() but won't flood the log.
@@ -170,7 +170,7 @@ void drm_err(const char *func, const char *format, ...);
 				      DEFAULT_RATELIMIT_BURST);		\
 									\
 	if (__ratelimit(&_rs))						\
-		drm_err(__func__, fmt, ##__VA_ARGS__);			\
+		drm_err(fmt, ##__VA_ARGS__);				\
 })
 
 #define DRM_INFO(fmt, ...)				\