[SRU][N][PATCH 1/1] fbdev: Introduce devm_register_framebuffer()

[marcin.wilk at canonical.com]

From: Marcin Wilk <marcin.wilk at canonical.com>

From: Thomas Weißschuh <linux at weissschuh.net>

BugLink: https://bugs.launchpad.net/bugs/2127971

Introduce a device-managed variant of register_framebuffer() which
automatically unregisters the framebuffer on device destruction.
This can simplify the error handling and resource management in drivers.

Signed-off-by: Thomas Weißschuh <linux at weissschuh.net>
Signed-off-by: Helge Deller <deller at gmx.de>
(cherry picked from commit 929c81ade6355b87097a2a4886c10750e68626cf)
Signed-off-by: Marcin Wilk <marcin.wilk at canonical.com>
---
 drivers/video/fbdev/core/fbmem.c | 30 ++++++++++++++++++++++++++++++
 include/linux/fb.h               |  1 +
 2 files changed, 31 insertions(+)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index fc206755f5f6..84f617606e5e 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -544,6 +544,36 @@ unregister_framebuffer(struct fb_info *fb_info)
 }
 EXPORT_SYMBOL(unregister_framebuffer);
 
+static void devm_unregister_framebuffer(void *data)
+{
+	struct fb_info *info = data;
+
+	unregister_framebuffer(info);
+}
+
+/**
+ *	devm_register_framebuffer - resource-managed frame buffer device registration
+ *	@dev: device the framebuffer belongs to
+ *	@fb_info: frame buffer info structure
+ *
+ *	Registers a frame buffer device @fb_info to device @dev.
+ *
+ *	Returns negative errno on error, or zero for success.
+ *
+ */
+int
+devm_register_framebuffer(struct device *dev, struct fb_info *fb_info)
+{
+	int ret;
+
+	ret = register_framebuffer(fb_info);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, devm_unregister_framebuffer, fb_info);
+}
+EXPORT_SYMBOL(devm_register_framebuffer);
+
 /**
  *	fb_set_suspend - low level driver signals suspend
  *	@info: framebuffer affected
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 25ca209e4d21..742b94931af4 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -592,6 +592,7 @@ extern ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
 /* fbmem.c */
 extern int register_framebuffer(struct fb_info *fb_info);
 extern void unregister_framebuffer(struct fb_info *fb_info);
+extern int devm_register_framebuffer(struct device *dev, struct fb_info *fb_info);
 extern char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size);
 extern void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 idx,
 				u32 height, u32 shift_high, u32 shift_low, u32 mod);
-- 
2.43.0