Commit 0b78f8bc authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Daniel Vetter
Browse files

Revert "fb_defio: Remove custom address_space_operations" 



Commit ccf953d8 makes framebuffers which use deferred I/O stop
displaying updates after the first one.  This is because the pages
handled by fb_defio no longer have a page_mapping().  That prevents
page_mkclean() from marking the PTEs as clean, and so writes are only
noticed the first time.

Reported-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/YLZEhv0cpZp8uVE3@casper.infradead.org
parent 8124c8a6

drivers/video/fbdev/core/fb_defio.c

+35 −0
Original line number Diff line number Diff line
@@ -52,6 +52,13 @@ static vm_fault_t fb_deferred_io_fault(struct vm_fault *vmf) 
		return VM_FAULT_SIGBUS;



	get_page(page);



	if (vmf->vma->vm_file)

		page->mapping = vmf->vma->vm_file->f_mapping;

	else

		printk(KERN_ERR "no mapping available\n");



	BUG_ON(!page->mapping);

	page->index = vmf->pgoff;



	vmf->page = page;
@@ -144,6 +151,17 @@ static const struct vm_operations_struct fb_deferred_io_vm_ops = { 
	.page_mkwrite	= fb_deferred_io_mkwrite,

};



static int fb_deferred_io_set_page_dirty(struct page *page)

{

	if (!PageDirty(page))

		SetPageDirty(page);

	return 0;

}



static const struct address_space_operations fb_deferred_io_aops = {

	.set_page_dirty = fb_deferred_io_set_page_dirty,

};



int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)

{

	vma->vm_ops = &fb_deferred_io_vm_ops;
@@ -194,12 +212,29 @@ void fb_deferred_io_init(struct fb_info *info) 
}

EXPORT_SYMBOL_GPL(fb_deferred_io_init);



void fb_deferred_io_open(struct fb_info *info,

			 struct inode *inode,

			 struct file *file)

{

	file->f_mapping->a_ops = &fb_deferred_io_aops;

}

EXPORT_SYMBOL_GPL(fb_deferred_io_open);



void fb_deferred_io_cleanup(struct fb_info *info)

{

	struct fb_deferred_io *fbdefio = info->fbdefio;

	struct page *page;

	int i;



	BUG_ON(!fbdefio);

	cancel_delayed_work_sync(&info->deferred_work);



	/* clear out the mapping that we setup */

	for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {

		page = fb_deferred_io_page(info, i);

		page->mapping = NULL;

	}



	mutex_destroy(&fbdefio->lock);

}

EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);

drivers/video/fbdev/core/fbmem.c

+4 −0
Original line number Diff line number Diff line
@@ -1415,6 +1415,10 @@ __releases(&info->lock) 
		if (res)

			module_put(info->fbops->owner);

	}

#ifdef CONFIG_FB_DEFERRED_IO

	if (info->fbdefio)

		fb_deferred_io_open(info, inode, file);

#endif

out:

	unlock_fb_info(info);

	if (res)

include/linux/fb.h

+3 −0
Original line number Diff line number Diff line
@@ -659,6 +659,9 @@ 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,

				struct file *file);

extern void fb_deferred_io_cleanup(struct fb_info *info);

extern int fb_deferred_io_fsync(struct file *file, loff_t start,

				loff_t end, int datasync);