From patchwork Fri Dec 11 17:25:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Trond Myklebust X-Patchwork-Id: 11969229 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE07AC433FE for ; Fri, 11 Dec 2020 19:12:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A939322D03 for ; Fri, 11 Dec 2020 19:12:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404179AbgLKR1u (ORCPT ); Fri, 11 Dec 2020 12:27:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:50804 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2395226AbgLKR0o (ORCPT ); Fri, 11 Dec 2020 12:26:44 -0500 From: trondmy@kernel.org Authentication-Results: mail.kernel.org; dkim=permerror (bad message/signature format) To: linux-nfs@vger.kernel.org Subject: [PATCH v2 08/15] SUNRPC: When expanding the buffer, we may need grow the sparse pages Date: Fri, 11 Dec 2020 12:25:14 -0500 Message-Id: <20201211172521.5567-9-trondmy@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201211172521.5567-8-trondmy@kernel.org> References: <20201211172521.5567-1-trondmy@kernel.org> <20201211172521.5567-2-trondmy@kernel.org> <20201211172521.5567-3-trondmy@kernel.org> <20201211172521.5567-4-trondmy@kernel.org> <20201211172521.5567-5-trondmy@kernel.org> <20201211172521.5567-6-trondmy@kernel.org> <20201211172521.5567-7-trondmy@kernel.org> <20201211172521.5567-8-trondmy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Trond Myklebust If we're shifting the page data to the right, and this happens to be a sparse page array, then we may need to allocate new pages in order to receive the data. Reported-by: "Mkrtchyan, Tigran" Signed-off-by: Trond Myklebust --- net/sunrpc/xdr.c | 35 +++++++++++++++++++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 2e91fbd70f11..60d4442c5273 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -478,16 +478,47 @@ static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase, } while ((len -= zero) != 0); } +static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf, + unsigned int buflen, gfp_t gfp) +{ + unsigned int i, npages, pagelen; + + if (!(buf->flags & XDRBUF_SPARSE_PAGES)) + return buflen; + if (buflen <= buf->head->iov_len) + return buflen; + pagelen = buflen - buf->head->iov_len; + if (pagelen > buf->page_len) + pagelen = buf->page_len; + npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT; + for (i = 0; i < npages; i++) { + if (!buf->pages[i]) + continue; + buf->pages[i] = alloc_page(gfp); + if (likely(buf->pages[i])) + continue; + buflen -= pagelen; + pagelen = i << PAGE_SHIFT; + if (pagelen > buf->page_base) + buflen += pagelen - buf->page_base; + break; + } + return buflen; +} + static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len) { struct kvec *head = buf->head; struct kvec *tail = buf->tail; unsigned int sum = head->iov_len + buf->page_len + tail->iov_len; - unsigned int free_space; + unsigned int free_space, newlen; if (sum > buf->len) { free_space = min_t(unsigned int, sum - buf->len, len); - buf->len += free_space; + newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space, + GFP_KERNEL); + free_space = newlen - buf->len; + buf->len = newlen; len -= free_space; if (!len) return;