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[68.40.195.73]) by smtp.gmail.com with ESMTPSA id b13sm4289183iot.70.2018.12.02.14.39.12 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 02 Dec 2018 14:39:12 -0800 (PST) From: Trond Myklebust X-Google-Original-From: Trond Myklebust To: Chuck Lever Cc: linux-nfs@vger.kernel.org Subject: [PATCH] SUNRPC: Fix up handling of the XDRBUF_SPARSE_PAGES flag Date: Sun, 2 Dec 2018 17:38:05 -0500 Message-Id: <20181202223805.100675-1-trond.myklebust@hammerspace.com> X-Mailer: git-send-email 2.19.2 MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If the allocator fails before it has reached the target number of pages, then we need to recheck that we're not seeking past the page buffer. Signed-off-by: Trond Myklebust --- net/sunrpc/xprtsock.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index ae77c71c1f64..36647bfbd683 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -330,19 +330,15 @@ xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp) { size_t i,n; - if (!(buf->flags & XDRBUF_SPARSE_PAGES)) + if (!want || !(buf->flags & XDRBUF_SPARSE_PAGES)) return want; - if (want > buf->page_len) - want = buf->page_len; n = (buf->page_base + want + PAGE_SIZE - 1) >> PAGE_SHIFT; for (i = 0; i < n; i++) { if (buf->pages[i]) continue; buf->bvec[i].bv_page = buf->pages[i] = alloc_page(gfp); - if (!buf->pages[i]) { - buf->page_len = (i * PAGE_SIZE) - buf->page_base; - return buf->page_len; - } + if (!buf->pages[i]) + return (i * PAGE_SIZE) - buf->page_base; } return want; } @@ -404,10 +400,11 @@ xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags, seek -= buf->head[0].iov_len; offset += buf->head[0].iov_len; } - if (seek < buf->page_len) { - want = xs_alloc_sparse_pages(buf, - min_t(size_t, count - offset, buf->page_len), - GFP_NOWAIT); + + want = xs_alloc_sparse_pages(buf, + min_t(size_t, count - offset, buf->page_len), + GFP_NOWAIT); + if (seek < want) { ret = xs_read_bvec(sock, msg, flags, buf->bvec, xdr_buf_pagecount(buf), want + buf->page_base, @@ -421,9 +418,10 @@ xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags, goto eagain; seek = 0; } else { - seek -= buf->page_len; - offset += buf->page_len; + seek -= want; + offset += want; } + if (seek < buf->tail[0].iov_len) { want = min_t(size_t, count - offset, buf->tail[0].iov_len); ret = xs_read_kvec(sock, msg, flags, &buf->tail[0], want, seek);