From patchwork Sat Jul 29 15:31:49 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Varun Prakash X-Patchwork-Id: 9870029 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5525560365 for ; Sat, 29 Jul 2017 15:32:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3E0AF2880B for ; Sat, 29 Jul 2017 15:32:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3083728811; Sat, 29 Jul 2017 15:32:08 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A62EE2880B for ; Sat, 29 Jul 2017 15:32:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752596AbdG2PcG (ORCPT ); Sat, 29 Jul 2017 11:32:06 -0400 Received: from stargate.chelsio.com ([12.32.117.8]:60417 "EHLO stargate.chelsio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752505AbdG2PcG (ORCPT ); Sat, 29 Jul 2017 11:32:06 -0400 Received: from fcoe-test11.asicdesigners.com (fcoe-test11.blr.asicdesigners.com [10.193.185.180]) by stargate.chelsio.com (8.13.8/8.13.8) with ESMTP id v6TFVtxB013374; Sat, 29 Jul 2017 08:31:56 -0700 From: Varun Prakash To: nab@linux-iscsi.org Cc: target-devel@vger.kernel.org, indranil@chelsio.com, varun@chelsio.com Subject: [PATCH] cxgbit: fix sg_nents calculation Date: Sat, 29 Jul 2017 21:01:49 +0530 Message-Id: <1501342309-5433-1-git-send-email-varun@chelsio.com> X-Mailer: git-send-email 2.0.2 Sender: target-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The current logic of calculating sg_nents can fail if data_offset % PAGE_SIZE is not zero. For example - PAGE_SIZE = 4096 data_len = 3072 data_offset = 3072 As per current logic sg_nents = max(1UL, DIV_ROUND_UP(data_len, PAGE_SIZE)); sg_nents = max(1UL, DIV_ROUND_UP(3072, 4096)); sg_nents = 1 But as data_offset % PAGE_SIZE = 3072 we should skip 3072 bytes skip = 3K sg_nents = max(1UL, DIV_ROUND_UP(3K(skip) + 3K(data_len), 4K(PAGE_SIZE)); sg_nents = 2; This patch fixes this issue by adding skip to data_len. Signed-off-by: Varun Prakash --- drivers/target/iscsi/cxgbit/cxgbit_target.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/target/iscsi/cxgbit/cxgbit_target.c b/drivers/target/iscsi/cxgbit/cxgbit_target.c index dda13f1..514986b 100644 --- a/drivers/target/iscsi/cxgbit/cxgbit_target.c +++ b/drivers/target/iscsi/cxgbit/cxgbit_target.c @@ -827,7 +827,7 @@ cxgbit_put_login_tx(struct iscsi_conn *conn, struct iscsi_login *login, static void cxgbit_skb_copy_to_sg(struct sk_buff *skb, struct scatterlist *sg, - unsigned int nents) + unsigned int nents, u32 skip) { struct skb_seq_state st; const u8 *buf; @@ -846,7 +846,7 @@ cxgbit_skb_copy_to_sg(struct sk_buff *skb, struct scatterlist *sg, } consumed += sg_pcopy_from_buffer(sg, nents, (void *)buf, - buf_len, consumed); + buf_len, skip + consumed); } } @@ -912,7 +912,7 @@ cxgbit_handle_immediate_data(struct iscsi_cmd *cmd, struct iscsi_scsi_req *hdr, struct scatterlist *sg = &cmd->se_cmd.t_data_sg[0]; u32 sg_nents = max(1UL, DIV_ROUND_UP(pdu_cb->dlen, PAGE_SIZE)); - cxgbit_skb_copy_to_sg(csk->skb, sg, sg_nents); + cxgbit_skb_copy_to_sg(csk->skb, sg, sg_nents, 0); } cmd->write_data_done += pdu_cb->dlen; @@ -1069,11 +1069,13 @@ static int cxgbit_handle_iscsi_dataout(struct cxgbit_sock *csk) cmd->se_cmd.data_length); if (!(pdu_cb->flags & PDUCBF_RX_DATA_DDPD)) { + u32 skip = data_offset % PAGE_SIZE; + sg_off = data_offset / PAGE_SIZE; sg_start = &cmd->se_cmd.t_data_sg[sg_off]; - sg_nents = max(1UL, DIV_ROUND_UP(data_len, PAGE_SIZE)); + sg_nents = max(1UL, DIV_ROUND_UP(skip + data_len, PAGE_SIZE)); - cxgbit_skb_copy_to_sg(csk->skb, sg_start, sg_nents); + cxgbit_skb_copy_to_sg(csk->skb, sg_start, sg_nents, skip); } check_payload: