From patchwork Wed Jul 13 19:08:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anna Schumaker X-Patchwork-Id: 12917031 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 92F5BC43334 for ; Wed, 13 Jul 2022 19:08:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236659AbiGMTIj (ORCPT ); Wed, 13 Jul 2022 15:08:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236627AbiGMTIf (ORCPT ); Wed, 13 Jul 2022 15:08:35 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C751334 for ; Wed, 13 Jul 2022 12:08:32 -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 4C997B82131 for ; Wed, 13 Jul 2022 19:08:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD11BC341C0; Wed, 13 Jul 2022 19:08:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1657739310; bh=06tbDAIV50KkX1Rev4Q+dwEAZwyYL5nx50/XVjO3+DI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jV1WIvTnRf6N8dmGBqVdvItUps/vQB5sNtT44Z9FxIOu4TfTPKS93oQt4/7dleHnP E58emDZYt0MB2FmzbqAvra7IkqiI3EZqQ5vHsbTUDc8+WgYQDMiorzi+EIRhcmajfM f18Q6CjnWwZg/MRDKR5akQsqeqsHsr0ctUgBl8DXEoE7FlLwbCC5hn4gH9HSGa8X/P nUOrFohS4JLOGVGJwx1FmzG6ETuruTHb2j2FUCA3+Vr/hM6ShFD6Akx0VecOhWhGCQ ZtzvGu52G2nDoaCzwrxmzoSIp8GGyO+anAbTPeNEuqoxgIYAzMqaaOibN27/IycJ8N pYQZrdYjwT76g== From: Anna Schumaker To: linux-nfs@vger.kernel.org, chuck.lever@oracle.com Cc: anna@kernel.org Subject: [PATCH v2 4/6] SUNRPC: Introduce xdr_buf_nth_page_address() Date: Wed, 13 Jul 2022 15:08:23 -0400 Message-Id: <20220713190825.615678-5-anna@kernel.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220713190825.615678-1-anna@kernel.org> References: <20220713190825.615678-1-anna@kernel.org> 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 bdaf048edde0..79824fea4529 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 37956a274f81..88b28656a05d 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) {