From patchwork Fri Oct 30 12:23:45 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wan, Kaike" X-Patchwork-Id: 7526811 Return-Path: X-Original-To: patchwork-linux-rdma@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 7835C9F37F for ; Fri, 30 Oct 2015 12:23:59 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8D2D920787 for ; Fri, 30 Oct 2015 12:23:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 86D6A206E4 for ; Fri, 30 Oct 2015 12:23:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750971AbbJ3MX4 (ORCPT ); Fri, 30 Oct 2015 08:23:56 -0400 Received: from mga14.intel.com ([192.55.52.115]:43893 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750882AbbJ3MXz (ORCPT ); Fri, 30 Oct 2015 08:23:55 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP; 30 Oct 2015 05:23:55 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,218,1444719600"; d="scan'208";a="823106144" Received: from phlsvsds.ph.intel.com ([10.228.195.38]) by fmsmga001.fm.intel.com with ESMTP; 30 Oct 2015 05:23:54 -0700 Received: from phlsvsds.ph.intel.com (localhost.localdomain [127.0.0.1]) by phlsvsds.ph.intel.com (8.13.8/8.13.8) with ESMTP id t9UCNsg2018084; Fri, 30 Oct 2015 08:23:54 -0400 Received: (from kaikewan@localhost) by phlsvsds.ph.intel.com (8.13.8/8.13.8/Submit) id t9UCNsZH018077; Fri, 30 Oct 2015 08:23:54 -0400 X-Authentication-Warning: phlsvsds.ph.intel.com: kaikewan set sender to kaike.wan@intel.com using -f From: kaike.wan@intel.com To: linux-rdma@vger.kernel.org Cc: Kaike Wan Subject: [PATCH v2 1/1] IB/sa: Put netlink request into the request list before sending Date: Fri, 30 Oct 2015 08:23:45 -0400 Message-Id: <1446207825-17664-1-git-send-email-kaike.wan@intel.com> X-Mailer: git-send-email 1.7.1 Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Kaike Wan It was found by Saurabh Sengar that the netlink code tried to allocate memory with GFP_KERNEL while holding a spinlock. While it is possible to fix the issue by replacing GFP_KERNEL with GFP_ATOMIC, it is better to get rid of the spinlock while sending the packet. However, in order to protect against a race condition that a quick response may be received before the request is put on the request list, we need to put the request on the list first. Signed-off-by: Kaike Wan Reviewed-by: Jason Gunthorpe Reviewed-by: Ira Weiny Reported-by: Saurabh Sengar --- This patch is based on Doug's k.o/for-4.4 branch Changes since v1: -- Pass gfp_mask to ib_nl_send_msg for internal memory allocation, as suggested by Ira Weiny; -- Queue the netlink timeout work before the request is sent to avoid potential race condition where the query is freed by the response handler. drivers/infiniband/core/sa_query.c | 32 +++++++++++++++++--------------- 1 files changed, 17 insertions(+), 15 deletions(-) diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c index dcdaa79..1495c00 100644 --- a/drivers/infiniband/core/sa_query.c +++ b/drivers/infiniband/core/sa_query.c @@ -512,7 +512,7 @@ static int ib_nl_get_path_rec_attrs_len(ib_sa_comp_mask comp_mask) return len; } -static int ib_nl_send_msg(struct ib_sa_query *query) +static int ib_nl_send_msg(struct ib_sa_query *query, gfp_t gfp_mask) { struct sk_buff *skb = NULL; struct nlmsghdr *nlh; @@ -526,7 +526,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query) if (len <= 0) return -EMSGSIZE; - skb = nlmsg_new(len, GFP_KERNEL); + skb = nlmsg_new(len, gfp_mask); if (!skb) return -ENOMEM; @@ -544,7 +544,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query) /* Repair the nlmsg header length */ nlmsg_end(skb, nlh); - ret = ibnl_multicast(skb, nlh, RDMA_NL_GROUP_LS, GFP_KERNEL); + ret = ibnl_multicast(skb, nlh, RDMA_NL_GROUP_LS, gfp_mask); if (!ret) ret = len; else @@ -553,7 +553,7 @@ static int ib_nl_send_msg(struct ib_sa_query *query) return ret; } -static int ib_nl_make_request(struct ib_sa_query *query) +static int ib_nl_make_request(struct ib_sa_query *query, gfp_t gfp_mask) { unsigned long flags; unsigned long delay; @@ -562,25 +562,27 @@ static int ib_nl_make_request(struct ib_sa_query *query) INIT_LIST_HEAD(&query->list); query->seq = (u32)atomic_inc_return(&ib_nl_sa_request_seq); + /* Put the request on the list first.*/ spin_lock_irqsave(&ib_nl_request_lock, flags); - ret = ib_nl_send_msg(query); - if (ret <= 0) { - ret = -EIO; - goto request_out; - } else { - ret = 0; - } - delay = msecs_to_jiffies(sa_local_svc_timeout_ms); query->timeout = delay + jiffies; list_add_tail(&query->list, &ib_nl_request_list); /* Start the timeout if this is the only request */ if (ib_nl_request_list.next == &query->list) queue_delayed_work(ib_nl_wq, &ib_nl_timed_work, delay); - -request_out: spin_unlock_irqrestore(&ib_nl_request_lock, flags); + ret = ib_nl_send_msg(query, gfp_mask); + if (ret <= 0) { + ret = -EIO; + /* Remove the request */ + spin_lock_irqsave(&ib_nl_request_lock, flags); + list_del(&query->list); + spin_unlock_irqrestore(&ib_nl_request_lock, flags); + } else { + ret = 0; + } + return ret; } @@ -1108,7 +1110,7 @@ static int send_mad(struct ib_sa_query *query, int timeout_ms, gfp_t gfp_mask) if (query->flags & IB_SA_ENABLE_LOCAL_SERVICE) { if (!ibnl_chk_listeners(RDMA_NL_GROUP_LS)) { - if (!ib_nl_make_request(query)) + if (!ib_nl_make_request(query, gfp_mask)) return id; } ib_sa_disable_local_svc(query);