From patchwork Mon May 16 20:35:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Schumaker, Anna" X-Patchwork-Id: 12851426 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 9E353C433EF for ; Mon, 16 May 2022 21:01:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346609AbiEPVBj (ORCPT ); Mon, 16 May 2022 17:01:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348960AbiEPVBA (ORCPT ); Mon, 16 May 2022 17:01:00 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3FBD2BD2 for ; Mon, 16 May 2022 13:35:55 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 28606B8165E for ; Mon, 16 May 2022 20:35:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9EAD7C385AA; Mon, 16 May 2022 20:35:52 +0000 (UTC) From: Anna.Schumaker@Netapp.com To: steved@redhat.com, linux-nfs@vger.kernel.org Cc: Anna.Schumaker@Netapp.com Subject: [PATCH v1 4/6] SUNRPC: Introduce xdr_buf_nth_page_address() Date: Mon, 16 May 2022 16:35:47 -0400 Message-Id: <20220516203549.2605575-5-Anna.Schumaker@Netapp.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220516203549.2605575-1-Anna.Schumaker@Netapp.com> References: <20220516203549.2605575-1-Anna.Schumaker@Netapp.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Anna Schumaker For getting a pointer to the memory address represented by the nth page, along with the length of the data on that page. Signed-off-by: Anna Schumaker --- include/linux/sunrpc/xdr.h | 2 ++ net/sunrpc/xdr.c | 17 +++++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index 344c820484ba..b375b284afbe 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -137,6 +137,8 @@ void xdr_inline_pages(struct xdr_buf *, unsigned int, struct page **, unsigned int, unsigned int); void xdr_terminate_string(const struct xdr_buf *, const u32); size_t xdr_buf_pagecount(const struct xdr_buf *buf); +char *xdr_buf_nth_page_address(const struct xdr_buf *buf, unsigned int n, + unsigned int *len); int xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp); void xdr_free_bvec(struct xdr_buf *buf); diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 3ecc444b27be..0b378c80f5f5 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -140,6 +140,23 @@ size_t xdr_buf_pagecount(const struct xdr_buf *buf) return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT; } +char *xdr_buf_nth_page_address(const struct xdr_buf *buf, unsigned int n, + unsigned int *len) +{ + unsigned int pgbase = buf->page_base + (n * PAGE_SIZE); + struct page **pages = buf->pages; + struct page **page; + + if (n >= xdr_buf_pagecount(buf)) + return NULL; + + page = pages + (pgbase >> PAGE_SHIFT); + pgbase &= ~PAGE_MASK; + *len = min_t(size_t, PAGE_SIZE, buf->page_len - (n * PAGE_SIZE)); + return page_address(*page) + pgbase; +} +EXPORT_SYMBOL_GPL(xdr_buf_nth_page_address); + int xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp) {