[PATCH v2 02/12] fbdev: allow apertures == NULL in remove_conflicting_framebuffers()

[Michał Mirosław <mirq-linux@xxxxxxxxxxxx>]

Interpret (otherwise-invalid) NULL apertures argument to mean all-memory
range. This will allow to remove several duplicates of this code from
drivers in following patches.

Signed-off-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
[for v1]
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>

---
v2: added kerneldoc to corresponding DRM helper
---
 drivers/video/fbdev/core/fbmem.c | 14 ++++++++++++++
 include/drm/drm_fb_helper.h      | 10 ++++++++++
 2 files changed, 24 insertions(+)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 30a18d4c9de4..0df148eb4699 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1779,11 +1779,25 @@ int remove_conflicting_framebuffers(struct apertures_struct *a,
 				    const char *name, bool primary)
 {
 	int ret;
+	bool do_free = false;
+
+	if (!a) {
+		a = alloc_apertures(1);
+		if (!a)
+			return -ENOMEM;
+
+		a->ranges[0].base = 0;
+		a->ranges[0].size = ~0;
+		do_free = true;
+	}
 
 	mutex_lock(&registration_lock);
 	ret = do_remove_conflicting_framebuffers(a, name, primary);
 	mutex_unlock(&registration_lock);
 
+	if (do_free)
+		kfree(a);
+
 	return ret;
 }
 EXPORT_SYMBOL(remove_conflicting_framebuffers);
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index b069433e7fc1..1c1e53abb25d 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -566,6 +566,16 @@ static inline void drm_fb_helper_output_poll_changed(struct drm_device *dev)
 
 #endif
 
+/**
+ * drm_fb_helper_remove_conflicting_framebuffers - remove firmware framebuffers
+ * @a: memory range, users of which are to be removed
+ * @name: requesting driver name
+ * @primary: also kick vga16fb if present
+ *
+ * This function removes framebuffer devices (eg. initialized by firmware)
+ * which use memory range described by @a. If @a is NULL all such devices are
+ * removed.
+ */
 static inline int
 drm_fb_helper_remove_conflicting_framebuffers(struct apertures_struct *a,
 					      const char *name, bool primary)
-- 
2.18.0

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