From 56c134f7f1b58be08bdb0ca8372474a4a5165f31 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Fri, 29 Apr 2022 12:08:31 +0200
Subject: fbdev: Track deferred-I/O pages in pageref struct

Store the per-page state for fbdev's deferred I/O in struct
fb_deferred_io_pageref. Maintain a list of pagerefs for the pages
that have to be written back to video memory. Update all affected
drivers.

As with pages before, fbdev acquires a pageref when an mmaped page
of the framebuffer is being written to. It holds the pageref in a
list of all currently written pagerefs until it flushes the written
pages to video memory. Writeback occurs periodically. After writeback
fbdev releases all pagerefs and builds up a new dirty list until the
next writeback occurs.

Using pagerefs has a number of benefits.

For pages of the framebuffer, the deferred I/O code used struct
page.lru as an entry into the list of dirty pages. The lru field is
owned by the page cache, which makes deferred I/O incompatible with
some memory pages (e.g., most notably DRM's GEM SHMEM allocator).
struct fb_deferred_io_pageref now provides an entry into a list of
dirty framebuffer pages, freeing lru for use with the page cache.

Drivers also assumed that struct page.index is the page offset into
the framebuffer. This is not true for DRM buffers, which are located
at various offset within a mapped area. struct fb_deferred_io_pageref
explicitly stores an offset into the framebuffer. struct page.index
is now only the page offset into the mapped area.

These changes will allow DRM to use fbdev deferred I/O without an
intermediate shadow buffer.

v3:
	* use pageref->offset for sorting
	* fix grammar in comment
v2:
	* minor fixes in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-3-tzimmermann@suse.de
---
 include/linux/fb.h | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'include/linux')

diff --git a/include/linux/fb.h b/include/linux/fb.h
index f95da1af9ff6..a332590c0fae 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -201,6 +201,13 @@ struct fb_pixmap {
 };
 
 #ifdef CONFIG_FB_DEFERRED_IO
+struct fb_deferred_io_pageref {
+	struct page *page;
+	unsigned long offset;
+	/* private */
+	struct list_head list;
+};
+
 struct fb_deferred_io {
 	/* delay between mkwrite and deferred handler */
 	unsigned long delay;
@@ -468,6 +475,8 @@ struct fb_info {
 #endif
 #ifdef CONFIG_FB_DEFERRED_IO
 	struct delayed_work deferred_work;
+	unsigned long npagerefs;
+	struct fb_deferred_io_pageref *pagerefs;
 	struct fb_deferred_io *fbdefio;
 #endif
 
@@ -661,7 +670,7 @@ 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 int  fb_deferred_io_init(struct fb_info *info);
 extern void fb_deferred_io_open(struct fb_info *info,
 				struct inode *inode,
 				struct file *file);
-- 
cgit v1.2.3


From e80eec1b871a2acb8f5c92db4c237e9ae6dd322b Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Fri, 29 Apr 2022 12:08:33 +0200
Subject: fbdev: Rename pagelist to pagereflist for deferred I/O

Rename various instances of pagelist to pagereflist. The list now
stores pageref structures, so the new name is more appropriate.

In their write-back helpers, several fbdev drivers refer to the
pageref list in struct fb_deferred_io instead of using the one
supplied as argument to the function. Convert them over to the
supplied one. It's the same instance, so no change of behavior
occurs.

v4:
	* fix commit message (Javier)

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-5-tzimmermann@suse.de
---
 drivers/gpu/drm/drm_fb_helper.c        |  7 +++----
 drivers/gpu/drm/vmwgfx/vmwgfx_fb.c     |  5 ++---
 drivers/hid/hid-picolcd_fb.c           |  2 +-
 drivers/staging/fbtft/fbtft-core.c     | 10 +++++-----
 drivers/video/fbdev/broadsheetfb.c     | 12 +++++-------
 drivers/video/fbdev/core/fb_defio.c    | 18 +++++++++---------
 drivers/video/fbdev/hecubafb.c         |  3 +--
 drivers/video/fbdev/hyperv_fb.c        |  5 ++---
 drivers/video/fbdev/metronomefb.c      | 12 +++++-------
 drivers/video/fbdev/sh_mobile_lcdcfb.c | 16 +++++++---------
 drivers/video/fbdev/smscufx.c          |  8 +++-----
 drivers/video/fbdev/ssd1307fb.c        |  3 +--
 drivers/video/fbdev/udlfb.c            |  8 +++-----
 drivers/video/fbdev/xen-fbfront.c      |  5 ++---
 include/drm/drm_fb_helper.h            |  3 +--
 include/linux/fb.h                     |  6 +++---
 16 files changed, 53 insertions(+), 70 deletions(-)

(limited to 'include/linux')

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index dd1d72d58b35..5ad2b6a2778c 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -708,13 +708,12 @@ static void drm_fb_helper_memory_range_to_clip(struct fb_info *info, off_t off,
 /**
  * drm_fb_helper_deferred_io() - fbdev deferred_io callback function
  * @info: fb_info struct pointer
- * @pagelist: list of mmap framebuffer pages that have to be flushed
+ * @pagereflist: list of mmap framebuffer pages that have to be flushed
  *
  * This function is used as the &fb_deferred_io.deferred_io
  * callback function for flushing the fbdev mmap writes.
  */
-void drm_fb_helper_deferred_io(struct fb_info *info,
-			       struct list_head *pagelist)
+void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	unsigned long start, end, min, max;
 	struct fb_deferred_io_pageref *pageref;
@@ -722,7 +721,7 @@ void drm_fb_helper_deferred_io(struct fb_info *info,
 
 	min = ULONG_MAX;
 	max = 0;
-	list_for_each_entry(pageref, pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		start = pageref->offset;
 		end = start + PAGE_SIZE;
 		min = min(min, start);
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
index db02e17e12b6..9a3dc5c4eec8 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
@@ -316,8 +316,7 @@ static int vmw_fb_pan_display(struct fb_var_screeninfo *var,
 	return 0;
 }
 
-static void vmw_deferred_io(struct fb_info *info,
-			    struct list_head *pagelist)
+static void vmw_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	struct vmw_fb_par *par = info->par;
 	unsigned long start, end, min, max;
@@ -327,7 +326,7 @@ static void vmw_deferred_io(struct fb_info *info,
 
 	min = ULONG_MAX;
 	max = 0;
-	list_for_each_entry(pageref, pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		struct page *page = pageref->page;
 		start = page->index << PAGE_SHIFT;
 		end = start + PAGE_SIZE - 1;
diff --git a/drivers/hid/hid-picolcd_fb.c b/drivers/hid/hid-picolcd_fb.c
index 78515e6bacf0..de61c08fabea 100644
--- a/drivers/hid/hid-picolcd_fb.c
+++ b/drivers/hid/hid-picolcd_fb.c
@@ -433,7 +433,7 @@ static const struct fb_ops picolcdfb_ops = {
 
 
 /* Callback from deferred IO workqueue */
-static void picolcd_fb_deferred_io(struct fb_info *info, struct list_head *pagelist)
+static void picolcd_fb_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	picolcd_fb_update(info);
 }
diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index e9662822e1ef..8774bffe94cc 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -322,7 +322,7 @@ static void fbtft_mkdirty(struct fb_info *info, int y, int height)
 	schedule_delayed_work(&info->deferred_work, fbdefio->delay);
 }
 
-static void fbtft_deferred_io(struct fb_info *info, struct list_head *pagelist)
+static void fbtft_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	struct fbtft_par *par = info->par;
 	unsigned int dirty_lines_start, dirty_lines_end;
@@ -340,7 +340,7 @@ static void fbtft_deferred_io(struct fb_info *info, struct list_head *pagelist)
 	spin_unlock(&par->dirty_lock);
 
 	/* Mark display lines as dirty */
-	list_for_each_entry(pageref, pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		struct page *page = pageref->page;
 		count++;
 		index = page->index << PAGE_SHIFT;
@@ -655,9 +655,9 @@ struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 	fbops->fb_blank     =      fbtft_fb_blank;
 	fbops->fb_mmap      =      fb_deferred_io_mmap;
 
-	fbdefio->delay =           HZ / fps;
-	fbdefio->sort_pagelist =   true;
-	fbdefio->deferred_io =     fbtft_deferred_io;
+	fbdefio->delay =            HZ / fps;
+	fbdefio->sort_pagereflist = true;
+	fbdefio->deferred_io =      fbtft_deferred_io;
 	fb_deferred_io_init(info);
 
 	snprintf(info->fix.id, sizeof(info->fix.id), "%s", dev->driver->name);
diff --git a/drivers/video/fbdev/broadsheetfb.c b/drivers/video/fbdev/broadsheetfb.c
index 6afc6ef4cb5e..883a3ac03189 100644
--- a/drivers/video/fbdev/broadsheetfb.c
+++ b/drivers/video/fbdev/broadsheetfb.c
@@ -929,13 +929,11 @@ static void broadsheetfb_dpy_update(struct broadsheetfb_par *par)
 }
 
 /* this is called back from the deferred io workqueue */
-static void broadsheetfb_dpy_deferred_io(struct fb_info *info,
-				struct list_head *pagelist)
+static void broadsheetfb_dpy_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	u16 y1 = 0, h = 0;
 	int prev_index = -1;
 	struct fb_deferred_io_pageref *pageref;
-	struct fb_deferred_io *fbdefio = info->fbdefio;
 	int h_inc;
 	u16 yres = info->var.yres;
 	u16 xres = info->var.xres;
@@ -944,7 +942,7 @@ static void broadsheetfb_dpy_deferred_io(struct fb_info *info,
 	h_inc = DIV_ROUND_UP(PAGE_SIZE , xres);
 
 	/* walk the written page list and swizzle the data */
-	list_for_each_entry(pageref, &fbdefio->pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		struct page *cur = pageref->page;
 		if (prev_index < 0) {
 			/* just starting so assign first page */
@@ -1060,9 +1058,9 @@ static const struct fb_ops broadsheetfb_ops = {
 };
 
 static struct fb_deferred_io broadsheetfb_defio = {
-	.delay		= HZ/4,
-	.sort_pagelist	= true,
-	.deferred_io	= broadsheetfb_dpy_deferred_io,
+	.delay			= HZ/4,
+	.sort_pagereflist	= true,
+	.deferred_io		= broadsheetfb_dpy_deferred_io,
 };
 
 static int broadsheetfb_probe(struct platform_device *dev)
diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c
index 3f9bb4725119..c730253ab85c 100644
--- a/drivers/video/fbdev/core/fb_defio.c
+++ b/drivers/video/fbdev/core/fb_defio.c
@@ -41,7 +41,7 @@ static struct fb_deferred_io_pageref *fb_deferred_io_pageref_get(struct fb_info
 								 struct page *page)
 {
 	struct fb_deferred_io *fbdefio = info->fbdefio;
-	struct list_head *pos = &fbdefio->pagelist;
+	struct list_head *pos = &fbdefio->pagereflist;
 	unsigned long pgoff = offset >> PAGE_SHIFT;
 	struct fb_deferred_io_pageref *pageref, *cur;
 
@@ -63,7 +63,7 @@ static struct fb_deferred_io_pageref *fb_deferred_io_pageref_get(struct fb_info
 	pageref->page = page;
 	pageref->offset = pgoff << PAGE_SHIFT;
 
-	if (unlikely(fbdefio->sort_pagelist)) {
+	if (unlikely(fbdefio->sort_pagereflist)) {
 		/*
 		 * We loop through the list of pagerefs before adding in
 		 * order to keep the pagerefs sorted. This has significant
@@ -71,7 +71,7 @@ static struct fb_deferred_io_pageref *fb_deferred_io_pageref_get(struct fb_info
 		 * pages. If possible, drivers should try to work with
 		 * unsorted page lists instead.
 		 */
-		list_for_each_entry(cur, &info->fbdefio->pagelist, list) {
+		list_for_each_entry(cur, &fbdefio->pagereflist, list) {
 			if (cur->offset > pageref->offset)
 				break;
 		}
@@ -158,7 +158,7 @@ static vm_fault_t fb_deferred_io_track_page(struct fb_info *info, unsigned long
 	mutex_lock(&fbdefio->lock);
 
 	/* first write in this cycle, notify the driver */
-	if (fbdefio->first_io && list_empty(&fbdefio->pagelist))
+	if (fbdefio->first_io && list_empty(&fbdefio->pagereflist))
 		fbdefio->first_io(info);
 
 	pageref = fb_deferred_io_pageref_get(info, offset, page);
@@ -249,18 +249,18 @@ static void fb_deferred_io_work(struct work_struct *work)
 
 	/* here we mkclean the pages, then do all deferred IO */
 	mutex_lock(&fbdefio->lock);
-	list_for_each_entry(pageref, &fbdefio->pagelist, list) {
+	list_for_each_entry(pageref, &fbdefio->pagereflist, list) {
 		struct page *cur = pageref->page;
 		lock_page(cur);
 		page_mkclean(cur);
 		unlock_page(cur);
 	}
 
-	/* driver's callback with pagelist */
-	fbdefio->deferred_io(info, &fbdefio->pagelist);
+	/* driver's callback with pagereflist */
+	fbdefio->deferred_io(info, &fbdefio->pagereflist);
 
 	/* clear the list */
-	list_for_each_entry_safe(pageref, next, &fbdefio->pagelist, list)
+	list_for_each_entry_safe(pageref, next, &fbdefio->pagereflist, list)
 		fb_deferred_io_pageref_put(pageref, info);
 
 	mutex_unlock(&fbdefio->lock);
@@ -280,7 +280,7 @@ int fb_deferred_io_init(struct fb_info *info)
 
 	mutex_init(&fbdefio->lock);
 	INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
-	INIT_LIST_HEAD(&fbdefio->pagelist);
+	INIT_LIST_HEAD(&fbdefio->pagereflist);
 	if (fbdefio->delay == 0) /* set a default of 1 s */
 		fbdefio->delay = HZ;
 
diff --git a/drivers/video/fbdev/hecubafb.c b/drivers/video/fbdev/hecubafb.c
index 2c483e2cf9ec..eb1eaadc1bbb 100644
--- a/drivers/video/fbdev/hecubafb.c
+++ b/drivers/video/fbdev/hecubafb.c
@@ -115,8 +115,7 @@ static void hecubafb_dpy_update(struct hecubafb_par *par)
 }
 
 /* this is called back from the deferred io workqueue */
-static void hecubafb_dpy_deferred_io(struct fb_info *info,
-				struct list_head *pagelist)
+static void hecubafb_dpy_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	hecubafb_dpy_update(info->par);
 }
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 51eb57ea68f7..550cf0990070 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -420,8 +420,7 @@ static void hvfb_docopy(struct hvfb_par *par,
 }
 
 /* Deferred IO callback */
-static void synthvid_deferred_io(struct fb_info *p,
-				 struct list_head *pagelist)
+static void synthvid_deferred_io(struct fb_info *p, struct list_head *pagereflist)
 {
 	struct hvfb_par *par = p->par;
 	struct fb_deferred_io_pageref *pageref;
@@ -437,7 +436,7 @@ static void synthvid_deferred_io(struct fb_info *p,
 	 * in synthvid_update function by clamping the y2
 	 * value to yres.
 	 */
-	list_for_each_entry(pageref, pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		struct page *page = pageref->page;
 		start = page->index << PAGE_SHIFT;
 		end = start + PAGE_SIZE - 1;
diff --git a/drivers/video/fbdev/metronomefb.c b/drivers/video/fbdev/metronomefb.c
index 8352fa3f4cef..f581c73d39df 100644
--- a/drivers/video/fbdev/metronomefb.c
+++ b/drivers/video/fbdev/metronomefb.c
@@ -465,16 +465,14 @@ static u16 metronomefb_dpy_update_page(struct metronomefb_par *par, int index)
 }
 
 /* this is called back from the deferred io workqueue */
-static void metronomefb_dpy_deferred_io(struct fb_info *info,
-				struct list_head *pagelist)
+static void metronomefb_dpy_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	u16 cksum;
 	struct fb_deferred_io_pageref *pageref;
-	struct fb_deferred_io *fbdefio = info->fbdefio;
 	struct metronomefb_par *par = info->par;
 
 	/* walk the written page list and swizzle the data */
-	list_for_each_entry(pageref, &fbdefio->pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		struct page *cur = pageref->page;
 		cksum = metronomefb_dpy_update_page(par,
 					(cur->index << PAGE_SHIFT));
@@ -569,9 +567,9 @@ static const struct fb_ops metronomefb_ops = {
 };
 
 static struct fb_deferred_io metronomefb_defio = {
-	.delay		= HZ,
-	.sort_pagelist	= true,
-	.deferred_io	= metronomefb_dpy_deferred_io,
+	.delay			= HZ,
+	.sort_pagereflist	= true,
+	.deferred_io		= metronomefb_dpy_deferred_io,
 };
 
 static int metronomefb_probe(struct platform_device *dev)
diff --git a/drivers/video/fbdev/sh_mobile_lcdcfb.c b/drivers/video/fbdev/sh_mobile_lcdcfb.c
index aea0660ba0c3..2b060eca4360 100644
--- a/drivers/video/fbdev/sh_mobile_lcdcfb.c
+++ b/drivers/video/fbdev/sh_mobile_lcdcfb.c
@@ -435,8 +435,7 @@ static struct sh_mobile_lcdc_sys_bus_ops sh_mobile_lcdc_sys_bus_ops = {
 	.read_data	= lcdc_sys_read_data,
 };
 
-static int sh_mobile_lcdc_sginit(struct fb_info *info,
-				  struct list_head *pagelist)
+static int sh_mobile_lcdc_sginit(struct fb_info *info, struct list_head *pagereflist)
 {
 	struct sh_mobile_lcdc_chan *ch = info->par;
 	unsigned int nr_pages_max = ch->fb_size >> PAGE_SHIFT;
@@ -445,7 +444,7 @@ static int sh_mobile_lcdc_sginit(struct fb_info *info,
 
 	sg_init_table(ch->sglist, nr_pages_max);
 
-	list_for_each_entry(pageref, pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		struct page *page = pageref->page;
 		sg_set_page(&ch->sglist[nr_pages++], page, PAGE_SIZE, 0);
 	}
@@ -453,8 +452,7 @@ static int sh_mobile_lcdc_sginit(struct fb_info *info,
 	return nr_pages;
 }
 
-static void sh_mobile_lcdc_deferred_io(struct fb_info *info,
-				       struct list_head *pagelist)
+static void sh_mobile_lcdc_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	struct sh_mobile_lcdc_chan *ch = info->par;
 	const struct sh_mobile_lcdc_panel_cfg *panel = &ch->cfg->panel_cfg;
@@ -463,7 +461,7 @@ static void sh_mobile_lcdc_deferred_io(struct fb_info *info,
 	sh_mobile_lcdc_clk_on(ch->lcdc);
 
 	/*
-	 * It's possible to get here without anything on the pagelist via
+	 * It's possible to get here without anything on the pagereflist via
 	 * sh_mobile_lcdc_deferred_io_touch() or via a userspace fsync()
 	 * invocation. In the former case, the acceleration routines are
 	 * stepped in to when using the framebuffer console causing the
@@ -473,12 +471,12 @@ static void sh_mobile_lcdc_deferred_io(struct fb_info *info,
 	 * acceleration routines have their own methods for writing in
 	 * that still need to be updated.
 	 *
-	 * The fsync() and empty pagelist case could be optimized for,
+	 * The fsync() and empty pagereflist case could be optimized for,
 	 * but we don't bother, as any application exhibiting such
 	 * behaviour is fundamentally broken anyways.
 	 */
-	if (!list_empty(pagelist)) {
-		unsigned int nr_pages = sh_mobile_lcdc_sginit(info, pagelist);
+	if (!list_empty(pagereflist)) {
+		unsigned int nr_pages = sh_mobile_lcdc_sginit(info, pagereflist);
 
 		/* trigger panel update */
 		dma_map_sg(ch->lcdc->dev, ch->sglist, nr_pages, DMA_TO_DEVICE);
diff --git a/drivers/video/fbdev/smscufx.c b/drivers/video/fbdev/smscufx.c
index eb108f56ea04..7f00605bc0d1 100644
--- a/drivers/video/fbdev/smscufx.c
+++ b/drivers/video/fbdev/smscufx.c
@@ -955,12 +955,10 @@ static void ufx_ops_fillrect(struct fb_info *info,
  *   Touching ANY framebuffer memory that triggers a page fault
  *   in fb_defio will cause a deadlock, when it also tries to
  *   grab the same mutex. */
-static void ufx_dpy_deferred_io(struct fb_info *info,
-				struct list_head *pagelist)
+static void ufx_dpy_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
-	struct fb_deferred_io_pageref *pageref;
-	struct fb_deferred_io *fbdefio = info->fbdefio;
 	struct ufx_data *dev = info->par;
+	struct fb_deferred_io_pageref *pageref;
 
 	if (!fb_defio)
 		return;
@@ -969,7 +967,7 @@ static void ufx_dpy_deferred_io(struct fb_info *info,
 		return;
 
 	/* walk the written page list and render each to device */
-	list_for_each_entry(pageref, &fbdefio->pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		/* create a rectangle of full screen width that encloses the
 		 * entire dirty framebuffer page */
 		struct page *cur = pageref->page;
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 7547b4628afc..5c765655d000 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -371,8 +371,7 @@ static const struct fb_ops ssd1307fb_ops = {
 	.fb_mmap	= fb_deferred_io_mmap,
 };
 
-static void ssd1307fb_deferred_io(struct fb_info *info,
-				struct list_head *pagelist)
+static void ssd1307fb_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	ssd1307fb_update_display(info->par);
 }
diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
index f70b9cc8e855..66eefd317431 100644
--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -781,11 +781,9 @@ static void dlfb_ops_fillrect(struct fb_info *info,
  *   in fb_defio will cause a deadlock, when it also tries to
  *   grab the same mutex.
  */
-static void dlfb_dpy_deferred_io(struct fb_info *info,
-				struct list_head *pagelist)
+static void dlfb_dpy_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
 	struct fb_deferred_io_pageref *pageref;
-	struct fb_deferred_io *fbdefio = info->fbdefio;
 	struct dlfb_data *dlfb = info->par;
 	struct urb *urb;
 	char *cmd;
@@ -811,7 +809,7 @@ static void dlfb_dpy_deferred_io(struct fb_info *info,
 	cmd = urb->transfer_buffer;
 
 	/* walk the written page list and render each to device */
-	list_for_each_entry(pageref, &fbdefio->pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		struct page *cur = pageref->page;
 
 		if (dlfb_render_hline(dlfb, &urb, (char *) info->fix.smem_start,
@@ -984,7 +982,7 @@ static int dlfb_ops_open(struct fb_info *info, int user)
 
 		if (fbdefio) {
 			fbdefio->delay = DL_DEFIO_WRITE_DELAY;
-			fbdefio->sort_pagelist = true;
+			fbdefio->sort_pagereflist = true;
 			fbdefio->deferred_io = dlfb_dpy_deferred_io;
 		}
 
diff --git a/drivers/video/fbdev/xen-fbfront.c b/drivers/video/fbdev/xen-fbfront.c
index 608fcde767d3..bc8244b9ce03 100644
--- a/drivers/video/fbdev/xen-fbfront.c
+++ b/drivers/video/fbdev/xen-fbfront.c
@@ -181,8 +181,7 @@ static void xenfb_refresh(struct xenfb_info *info,
 		xenfb_do_update(info, x1, y1, x2 - x1 + 1, y2 - y1 + 1);
 }
 
-static void xenfb_deferred_io(struct fb_info *fb_info,
-			      struct list_head *pagelist)
+static void xenfb_deferred_io(struct fb_info *fb_info, struct list_head *pagereflist)
 {
 	struct xenfb_info *info = fb_info->par;
 	struct fb_deferred_io_pageref *pageref;
@@ -191,7 +190,7 @@ static void xenfb_deferred_io(struct fb_info *fb_info,
 
 	miny = INT_MAX;
 	maxy = 0;
-	list_for_each_entry(pageref, pagelist, list) {
+	list_for_each_entry(pageref, pagereflist, list) {
 		struct page *page = pageref->page;
 		beg = page->index << PAGE_SHIFT;
 		end = beg + PAGE_SIZE - 1;
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 3af4624368d8..329607ca65c0 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -229,8 +229,7 @@ void drm_fb_helper_fill_info(struct fb_info *info,
 			     struct drm_fb_helper *fb_helper,
 			     struct drm_fb_helper_surface_size *sizes);
 
-void drm_fb_helper_deferred_io(struct fb_info *info,
-			       struct list_head *pagelist);
+void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagereflist);
 
 ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
 			       size_t count, loff_t *ppos);
diff --git a/include/linux/fb.h b/include/linux/fb.h
index a332590c0fae..69c67c70fa78 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -211,9 +211,9 @@ struct fb_deferred_io_pageref {
 struct fb_deferred_io {
 	/* delay between mkwrite and deferred handler */
 	unsigned long delay;
-	bool sort_pagelist; /* sort pagelist by offset */
-	struct mutex lock; /* mutex that protects the page list */
-	struct list_head pagelist; /* list of touched pages */
+	bool sort_pagereflist; /* sort pagelist by offset */
+	struct mutex lock; /* mutex that protects the pageref list */
+	struct list_head pagereflist; /* list of pagerefs for touched pages */
 	/* callback */
 	void (*first_io)(struct fb_info *info);
 	void (*deferred_io)(struct fb_info *info, struct list_head *pagelist);
-- 
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