Simplify stop_machine

[linux-2.6-omap-h63xx.git] / drivers / video / fb_defio.c

diff --git a/drivers/video/fb_defio.c b/drivers/video/fb_defio.c
index 0f8cfb988c901a7f45314387149a759d8b252929..59df132cc3756deda96bfcce5d453a309e803a15 100644 (file)
--- a/drivers/video/fb_defio.c
+++ b/drivers/video/fb_defio.c
@@ -4,7 +4,7 @@
  *  Copyright (C) 2006 Jaya Kumar
  *
  * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file COPYING in the main directory of this archive
+ * License. See the file COPYING in the main directory of this archive
  * for more details.
  */
 
@@ -31,7 +31,7 @@ static int fb_deferred_io_fault(struct vm_area_struct *vma,
        unsigned long offset;
        struct page *page;
        struct fb_info *info = vma->vm_private_data;
-       /* info->screen_base is in System RAM */
+       /* info->screen_base is virtual memory */
        void *screen_base = (void __force *) info->screen_base;
 
        offset = vmf->pgoff << PAGE_SHIFT;
@@ -43,6 +43,15 @@ static int fb_deferred_io_fault(struct vm_area_struct *vma,
                return VM_FAULT_SIGBUS;
 
        get_page(page);
+
+       if (vma->vm_file)
+               page->mapping = vma->vm_file->f_mapping;
+       else
+               printk(KERN_ERR "no mapping available\n");
+
+       BUG_ON(!page->mapping);
+       page->index = vmf->pgoff;
+
        vmf->page = page;
        return 0;
 }
@@ -65,6 +74,7 @@ static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
 {
        struct fb_info *info = vma->vm_private_data;
        struct fb_deferred_io *fbdefio = info->fbdefio;
+       struct page *cur;
 
        /* this is a callback we get when userspace first tries to
        write to the page. we schedule a workqueue. that workqueue
@@ -74,7 +84,24 @@ static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
 
        /* protect against the workqueue changing the page list */
        mutex_lock(&fbdefio->lock);
-       list_add(&page->lru, &fbdefio->pagelist);
+
+       /* we loop through the pagelist before adding in order
+       to keep the pagelist sorted */
+       list_for_each_entry(cur, &fbdefio->pagelist, lru) {
+               /* this check is to catch the case where a new
+               process could start writing to the same page
+               through a new pte. this new access can cause the
+               mkwrite even when the original ps's pte is marked
+               writable */
+               if (unlikely(cur == page))
+                       goto page_already_added;
+               else if (cur->index > page->index)
+                       break;
+       }
+
+       list_add_tail(&page->lru, &cur->lru);
+
+page_already_added:
        mutex_unlock(&fbdefio->lock);
 
        /* come back after delay to process the deferred IO */
@@ -138,11 +165,20 @@ EXPORT_SYMBOL_GPL(fb_deferred_io_init);
 
 void fb_deferred_io_cleanup(struct fb_info *info)
 {
+       void *screen_base = (void __force *) info->screen_base;
        struct fb_deferred_io *fbdefio = info->fbdefio;
+       struct page *page;
+       int i;
 
        BUG_ON(!fbdefio);
        cancel_delayed_work(&info->deferred_work);
        flush_scheduled_work();
+
+       /* clear out the mapping that we setup */
+       for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
+               page = vmalloc_to_page(screen_base + i);
+               page->mapping = NULL;
+       }
 }
 EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);