diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c index 806ecd32219b..dc3b4dc4d507 100644 --- a/drivers/video/fbdev/core/fb_defio.c +++ b/drivers/video/fbdev/core/fb_defio.c @@ -36,20 +36,43 @@ static struct page *fb_deferred_io_page(struct fb_info *info, unsigned long offs return page; } +static struct fb_deferred_io_pageref *fb_deferred_io_pageref_lookup(struct fb_info *info, + unsigned long offset, + struct page *page) +{ + unsigned long pgoff = offset >> PAGE_SHIFT; + struct fb_deferred_io_pageref *pageref; + + if (fb_WARN_ON_ONCE(info, pgoff >= info->npagerefs)) + return NULL; /* incorrect allocation size */ + + /* 1:1 mapping between pageref and page offset */ + pageref = &info->pagerefs[pgoff]; + + if (pageref->page) + goto out; + + pageref->page = page; + pageref->offset = pgoff << PAGE_SHIFT; + INIT_LIST_HEAD(&pageref->list); + +out: + if (fb_WARN_ON_ONCE(info, pageref->page != page)) + return NULL; /* inconsistent state */ + return pageref; +} + static struct fb_deferred_io_pageref *fb_deferred_io_pageref_get(struct fb_info *info, unsigned long offset, struct page *page) { struct fb_deferred_io *fbdefio = info->fbdefio; struct list_head *pos = &fbdefio->pagereflist; - unsigned long pgoff = offset >> PAGE_SHIFT; struct fb_deferred_io_pageref *pageref, *cur; - if (WARN_ON_ONCE(pgoff >= info->npagerefs)) - return NULL; /* incorrect allocation size */ - - /* 1:1 mapping between pageref and page offset */ - pageref = &info->pagerefs[pgoff]; + pageref = fb_deferred_io_pageref_lookup(info, offset, page); + if (!pageref) + return NULL; /* * This check is to catch the case where a new process could start @@ -60,9 +83,6 @@ static struct fb_deferred_io_pageref *fb_deferred_io_pageref_get(struct fb_info if (!list_empty(&pageref->list)) goto pageref_already_added; - pageref->page = page; - pageref->offset = pgoff << PAGE_SHIFT; - if (unlikely(fbdefio->sort_pagereflist)) { /* * We loop through the list of pagerefs before adding in @@ -264,7 +284,7 @@ int fb_deferred_io_init(struct fb_info *info) { struct fb_deferred_io *fbdefio = info->fbdefio; struct fb_deferred_io_pageref *pagerefs; - unsigned long npagerefs, i; + unsigned long npagerefs; int ret; BUG_ON(!fbdefio); @@ -286,8 +306,6 @@ int fb_deferred_io_init(struct fb_info *info) ret = -ENOMEM; goto err; } - for (i = 0; i < npagerefs; ++i) - INIT_LIST_HEAD(&pagerefs[i].list); info->npagerefs = npagerefs; info->pagerefs = pagerefs;