diff options
| -rw-r--r-- | drivers/video/fb_defio.c | 40 |
1 files changed, 32 insertions, 8 deletions
diff --git a/drivers/video/fb_defio.c b/drivers/video/fb_defio.c index 6113c47e095a..1105a591dcc1 100644 --- a/drivers/video/fb_defio.c +++ b/drivers/video/fb_defio.c @@ -155,25 +155,41 @@ static void fb_deferred_io_work(struct work_struct *work) { struct fb_info *info = container_of(work, struct fb_info, deferred_work.work); - struct list_head *node, *next; - struct page *cur; struct fb_deferred_io *fbdefio = info->fbdefio; + struct page *page, *tmp_page; + struct list_head *node, *tmp_node; + struct list_head non_dirty; + + INIT_LIST_HEAD(&non_dirty); /* here we mkclean the pages, then do all deferred IO */ mutex_lock(&fbdefio->lock); - list_for_each_entry(cur, &fbdefio->pagelist, lru) { - lock_page(cur); - page_mkclean(cur); - unlock_page(cur); + list_for_each_entry_safe(page, tmp_page, &fbdefio->pagelist, lru) { + lock_page(page); + /* + * The workqueue callback can be triggered after a + * ->page_mkwrite() call but before the PTE has been marked + * dirty. In this case page_mkclean() won't "rearm" the page. + * + * To avoid this, remove those "non-dirty" pages from the + * pagelist before calling the driver's callback, then add + * them back to get processed on the next work iteration. + * At that time, their PTEs will hopefully be dirty for real. + */ + if (!page_mkclean(page)) + list_move_tail(&page->lru, &non_dirty); + unlock_page(page); } /* driver's callback with pagelist */ fbdefio->deferred_io(info, &fbdefio->pagelist); - /* clear the list */ - list_for_each_safe(node, next, &fbdefio->pagelist) { + /* clear the list... */ + list_for_each_safe(node, tmp_node, &fbdefio->pagelist) { list_del(node); } + /* ... and add back the "non-dirty" pages to the list */ + list_splice_tail(&non_dirty, &fbdefio->pagelist); mutex_unlock(&fbdefio->lock); } @@ -202,6 +218,7 @@ EXPORT_SYMBOL_GPL(fb_deferred_io_open); void fb_deferred_io_cleanup(struct fb_info *info) { struct fb_deferred_io *fbdefio = info->fbdefio; + struct list_head *node, *tmp_node; struct page *page; int i; @@ -209,6 +226,13 @@ void fb_deferred_io_cleanup(struct fb_info *info) cancel_delayed_work(&info->deferred_work); flush_scheduled_work(); + /* the list may have still some non-dirty pages at this point */ + mutex_lock(&fbdefio->lock); + list_for_each_safe(node, tmp_node, &fbdefio->pagelist) { + list_del(node); + } + mutex_unlock(&fbdefio->lock); + /* 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); |