drm: move drm_can_sleep() to drm_util.h

Move drm_can_sleep() out of drmP.h to allow users
to get rid of the drmP.h include.

There was no header file that was a good match for this helper function.
So add this to drm_util with the relevant includes.

Add include of drm_util.h to all users.

v2:
- Update comments to use kernel-doc style (Daniel)
- Add FIXME to drm_can_sleep and add note that this
  function should not be used in new code (Daniel)

v3:
- Fix kernel-doc syntax (Daniel)
- Plug drm_util.h into drm-internels.rst (Daniel)
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190112193251.20450-2-sam@ravnborg.org

Documentation/gpu/drm-internals.rst

@@ -233,6 +233,15 @@ Printer
 .. kernel-doc:: drivers/gpu/drm/drm_print.c
    :export:
 
+Utilities
+---------
+
+.. kernel-doc:: include/drm/drm_util.h
+   :doc: drm utils
+
+.. kernel-doc:: include/drm/drm_util.h
+   :internal:
+
 
 Legacy Support Code
 ===================

drivers/gpu/drm/amd/amdgpu/atom.c

@@ -27,6 +27,8 @@
 #include <linux/slab.h>
 #include <asm/unaligned.h>
 
+#include <drm/drm_util.h>
+
 #define ATOM_DEBUG
 
 #include "atom.h"

drivers/gpu/drm/ast/ast_fb.c

@@ -39,7 +39,9 @@
 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_fb_helper.h>
+#include <drm/drm_util.h>
 #include <drm/drm_crtc_helper.h>
+
 #include "ast_drv.h"
 
 static void ast_dirty_update(struct ast_fbdev *afbdev,

drivers/gpu/drm/cirrus/cirrus_fbdev.c

@@ -10,6 +10,7 @@
  */
 #include <linux/module.h>
 #include <drm/drmP.h>
+#include <drm/drm_util.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_crtc_helper.h>
 

drivers/gpu/drm/drm_flip_work.c

@@ -22,6 +22,7 @@
  */
 
 #include <drm/drmP.h>
+#include <drm/drm_util.h>
 #include <drm/drm_flip_work.h>
 
 /**

drivers/gpu/drm/mgag200/mgag200_fb.c

@@ -12,6 +12,7 @@
  */
 #include <linux/module.h>
 #include <drm/drmP.h>
+#include <drm/drm_util.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_crtc_helper.h>
 

drivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c

@@ -16,6 +16,7 @@
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <drm/drm_util.h>
 
 #include "mdp5_kms.h"
 #include "mdp5_smp.h"

drivers/gpu/drm/omapdrm/omap_fbdev.c

@@ -16,6 +16,7 @@
  */
 
 #include <drm/drm_crtc.h>
+#include <drm/drm_util.h>
 #include <drm/drm_fb_helper.h>
 
 #include "omap_drv.h"

drivers/gpu/drm/qxl/qxl_cmd.c

@@ -25,6 +25,8 @@
 
 /* QXL cmd/ring handling */
 
+#include <drm/drm_util.h>
+
 #include "qxl_drv.h"
 #include "qxl_object.h"
 

drivers/gpu/drm/radeon/atom.c

@@ -27,6 +27,8 @@
 #include <linux/slab.h>
 #include <asm/unaligned.h>
 
+#include <drm/drm_util.h>
+
 #define ATOM_DEBUG
 
 #include "atom.h"

drivers/gpu/drm/radeon/radeon_legacy_encoders.c

@@ -24,6 +24,7 @@
  *          Alex Deucher
  */
 #include <drm/drmP.h>
+#include <drm/drm_util.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/radeon_drm.h>
 #include "radeon.h"

drivers/gpu/drm/vc4/vc4_drv.h

@@ -9,6 +9,7 @@
 #include <linux/mm_types.h>
 #include <linux/reservation.h>
 #include <drm/drmP.h>
+#include <drm/drm_util.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_atomic.h>

include/drm/drmP.h

@@ -94,14 +94,6 @@ struct dma_buf_attachment;
 struct pci_dev;
 struct pci_controller;
 
-/* returns true if currently okay to sleep */
-static inline bool drm_can_sleep(void)
-{
-	if (in_atomic() || in_dbg_master() || irqs_disabled())
-		return false;
-	return true;
-}
-
 #if defined(CONFIG_DRM_DEBUG_SELFTEST_MODULE)
 #define EXPORT_SYMBOL_FOR_TESTS_ONLY(x) EXPORT_SYMBOL(x)
 #else

include/drm/drm_util.h

@@ -26,7 +26,48 @@
 #ifndef _DRM_UTIL_H_
 #define _DRM_UTIL_H_
 
-/* helper for handling conditionals in various for_each macros */
+/**
+ * DOC: drm utils
+ *
+ * Macros and inline functions that does not naturally belong in other places
+ */
+
+#include <linux/irqflags.h>
+#include <linux/preempt.h>
+#include <linux/kgdb.h>
+#include <linux/smp.h>
+
+/**
+ * for_each_if - helper for handling conditionals in various for_each macros
+ * @condition: The condition to check
+ *
+ * Typical use::
+ *
+ *	#define for_each_foo_bar(x, y) \'
+ *		list_for_each_entry(x, y->list, head) \'
+ *			for_each_if(x->something == SOMETHING)
+ *
+ * The for_each_if() macro makes the use of for_each_foo_bar() less error
+ * prone.
+ */
 #define for_each_if(condition) if (!(condition)) {} else
 
+/**
+ * drm_can_sleep - returns true if currently okay to sleep
+ *
+ * This function shall not be used in new code.
+ * The check for running in atomic context may not work - see linux/preempt.h.
+ *
+ * FIXME: All users of drm_can_sleep should be removed (see todo.rst)
+ *
+ * Returns:
+ * True if kgdb is active or we are in an atomic context or irqs are disabled
+ */
+static inline bool drm_can_sleep(void)
+{
+	if (in_atomic() || in_dbg_master() || irqs_disabled())
+		return false;
+	return true;
+}
+
 #endif