linux-kernel - [PATCH 5/8] fbdev: fb_defio: Export fb_deferred_io

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Date:	Wed, 20 Apr 2016 17:25:26 +0200
From:	Noralf Trønnes <noralf@...nnes.org>
To:	dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org
Cc:	daniel@...ll.ch, laurent.pinchart@...asonboard.com,
	tomi.valkeinen@...com, linux-kernel@...r.kernel.org,
	Noralf Trønnes <noralf@...nnes.org>
Subject: [PATCH 5/8] fbdev: fb_defio: Export fb_deferred_io_mmap

Export fb_deferred_io_mmap so drivers can change vma->vm_page_prot.
When the framebuffer memory is allocated using dma_alloc_writecombine()
instead of vmalloc(), I get cache syncing problems.
This solves it:

static int drm_fbdev_cma_deferred_io_mmap(struct fb_info *info,
					  struct vm_area_struct *vma)
{
	fb_deferred_io_mmap(info, vma);
	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	return 0;
}

Signed-off-by: Noralf Trønnes <noralf@...nnes.org>
---
 drivers/video/fbdev/core/fb_defio.c | 3 ++-
 include/linux/fb.h                  | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c
index 57721c7..74b5bca 100644
--- a/drivers/video/fbdev/core/fb_defio.c
+++ b/drivers/video/fbdev/core/fb_defio.c
@@ -164,7 +164,7 @@ static const struct address_space_operations fb_deferred_io_aops = {
 	.set_page_dirty = fb_deferred_io_set_page_dirty,
 };
 
-static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
+int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
 	vma->vm_ops = &fb_deferred_io_vm_ops;
 	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
@@ -173,6 +173,7 @@ static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
 	vma->vm_private_data = info;
 	return 0;
 }
+EXPORT_SYMBOL(fb_deferred_io_mmap);
 
 /* workqueue callback */
 static void fb_deferred_io_work(struct work_struct *work)
diff --git a/include/linux/fb.h b/include/linux/fb.h
index dfe8835..a964d07 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -673,6 +673,7 @@ static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch,
 }
 
 /* drivers/video/fb_defio.c */
+int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma);
 extern void fb_deferred_io_init(struct fb_info *info);
 extern void fb_deferred_io_open(struct fb_info *info,
 				struct inode *inode,
-- 
2.2.2