From patchwork Wed Jun 21 16:45:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 13287713 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BAB2DEB64DC for ; Wed, 21 Jun 2023 16:46:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230177AbjFUQqh (ORCPT ); Wed, 21 Jun 2023 12:46:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229814AbjFUQqZ (ORCPT ); Wed, 21 Jun 2023 12:46:25 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53169E9; Wed, 21 Jun 2023 09:46:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=jTDGdnu+fG/6kslyclH2srz/sHr6MJEFetnoOEAqThE=; b=J7syLfgLtqZEvF+FaGdNCpIxYK FGrBsHrwiUgwuOgUEvOX2i7PWXG/ZXhqiAhW6CpfyR4l4rDqNGULpmdUDJAIMFqrXnlWMyJuuuQew CRIwuxDz6BodPG9A2vL0dc3r9jSUjJ096kbZOKhyXbwTEF5WnPbOv35W1YxmyI5xeO3eW9SZeu6Ui elEI4SaI8VG431yTXK/Agfd1OvARTxSno98kcl4XPxpk7V8Q46NmOwcGLYx7LMoOCYaku65I0hGaM vfxZSH7R76ZxcVPpw10enxxDEKsn/iEIr1hxmLFS6RNnFgRQiKGzIC7i3HzHCE4ZskLC1FZi9nT0k 4UQzvpAA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qC0y1-00EjDk-FK; Wed, 21 Jun 2023 16:46:01 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org, Andrew Morton Cc: "Matthew Wilcox (Oracle)" , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 03/13] scatterlist: Add sg_set_folio() Date: Wed, 21 Jun 2023 17:45:47 +0100 Message-Id: <20230621164557.3510324-4-willy@infradead.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230621164557.3510324-1-willy@infradead.org> References: <20230621164557.3510324-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org This wrapper for sg_set_page() lets drivers add folios to a scatterlist more easily. We could, perhaps, do better by using a different page in the folio if offset is larger than UINT_MAX, but let's hope we get a better data structure than this before we need to care about such large folios. Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/scatterlist.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index ec46d8e8e49d..77df3d7b18a6 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -141,6 +141,30 @@ static inline void sg_set_page(struct scatterlist *sg, struct page *page, sg->length = len; } +/** + * sg_set_folio - Set sg entry to point at given folio + * @sg: SG entry + * @folio: The folio + * @len: Length of data + * @offset: Offset into folio + * + * Description: + * Use this function to set an sg entry pointing at a folio, never assign + * the folio directly. We encode sg table information in the lower bits + * of the folio pointer. See sg_page() for looking up the page belonging + * to an sg entry. + * + **/ +static inline void sg_set_folio(struct scatterlist *sg, struct folio *folio, + size_t len, size_t offset) +{ + WARN_ON_ONCE(len > UINT_MAX); + WARN_ON_ONCE(offset > UINT_MAX); + sg_assign_page(sg, &folio->page); + sg->offset = offset; + sg->length = len; +} + static inline struct page *sg_page(struct scatterlist *sg) { #ifdef CONFIG_DEBUG_SG