Looks good; my apologies for missing the leftover declaration of struct page in the same routine which you also found and removed this time around.
> On Mar 10, 2021, at 11:55 AM, Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> wrote:
>
> There's no need to give the page an address_space. Leaving the
> page->mapping as NULL will cause the VM to handle set_page_dirty()
> the same way that it's handled now, and that was the only reason to
> set the address_space in the first place.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
> ---
> v2: Delete local variable definitions
> drivers/video/fbdev/core/fb_defio.c | 35 -----------------------------
> drivers/video/fbdev/core/fbmem.c | 4 ----
> include/linux/fb.h | 3 ---
> 3 files changed, 42 deletions(-)
>
> diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c
> index a591d291b231..b292887a2481 100644
> --- a/drivers/video/fbdev/core/fb_defio.c
> +++ b/drivers/video/fbdev/core/fb_defio.c
> @@ -52,13 +52,6 @@ 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;
> @@ -151,17 +144,6 @@ 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;
> @@ -212,29 +194,12 @@ 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);
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> index 06f5805de2de..372b52a2befa 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -1415,10 +1415,6 @@ __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)
> diff --git a/include/linux/fb.h b/include/linux/fb.h
> index ecfbcc0553a5..a8dccd23c249 100644
> --- a/include/linux/fb.h
> +++ b/include/linux/fb.h
> @@ -659,9 +659,6 @@ 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);
> --
> 2.30.0
>
>
