From patchwork Fri May 30 23:18:41 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Chan X-Patchwork-Id: 354351 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 1A3501400AD for ; Sat, 31 May 2014 07:59:31 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934757AbaE3V7U (ORCPT ); Fri, 30 May 2014 17:59:20 -0400 Received: from mail-gw3-out.broadcom.com ([216.31.210.64]:52116 "EHLO mail-gw3-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934587AbaE3V7S (ORCPT ); Fri, 30 May 2014 17:59:18 -0400 X-IronPort-AV: E=Sophos;i="4.98,943,1392192000"; d="scan'208";a="31819805" Received: from irvexchcas07.broadcom.com (HELO IRVEXCHCAS07.corp.ad.broadcom.com) ([10.9.208.55]) by mail-gw3-out.broadcom.com with ESMTP; 30 May 2014 15:01:31 -0700 Received: from IRVEXCHSMTP1.corp.ad.broadcom.com (10.9.207.51) by IRVEXCHCAS07.corp.ad.broadcom.com (10.9.208.55) with Microsoft SMTP Server (TLS) id 14.3.174.1; Fri, 30 May 2014 14:59:17 -0700 Received: from mail-irva-13.broadcom.com (10.10.10.20) by IRVEXCHSMTP1.corp.ad.broadcom.com (10.9.207.51) with Microsoft SMTP Server id 14.3.174.1; Fri, 30 May 2014 14:59:17 -0700 Received: from dell (dhcp-10-12-137-145.irv.broadcom.com [10.12.137.145]) by mail-irva-13.broadcom.com (Postfix) with ESMTP id 486B29FF11; Fri, 30 May 2014 14:58:09 -0700 (PDT) From: Michael Chan To: CC: , , Michael Chan Subject: [PATCH 1/3] cnic: Don't take rcu_read_lock in cnic_rcv_netevent() Date: Fri, 30 May 2014 16:18:41 -0700 Message-ID: <1401491923-5480-2-git-send-email-mchan@broadcom.com> X-Mailer: git-send-email 1.5.5.GIT In-Reply-To: <1401491923-5480-1-git-send-email-mchan@broadcom.com> References: <1401491923-5480-1-git-send-email-mchan@broadcom.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Because the called function, such as bnx2fc_indicate_netevent(), can sleep, we cannot take rcu_lock(). To prevent the rcu protected ulp_ops from going away, we use the cnic_lock mutex and set the ULP_F_CALL_PENDING flag. The code already waits for ULP_F_CALL_PENDING flag to clear in cnic_unregister_device(). Signed-off-by: Michael Chan --- drivers/net/ethernet/broadcom/cnic.c | 15 +++++++++++---- 1 files changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/broadcom/cnic.c b/drivers/net/ethernet/broadcom/cnic.c index 09f3fef..7f40a2c 100644 --- a/drivers/net/ethernet/broadcom/cnic.c +++ b/drivers/net/ethernet/broadcom/cnic.c @@ -5624,20 +5624,27 @@ static void cnic_rcv_netevent(struct cnic_local *cp, unsigned long event, { int if_type; - rcu_read_lock(); for (if_type = 0; if_type < MAX_CNIC_ULP_TYPE; if_type++) { struct cnic_ulp_ops *ulp_ops; void *ctx; - ulp_ops = rcu_dereference(cp->ulp_ops[if_type]); - if (!ulp_ops || !ulp_ops->indicate_netevent) + mutex_lock(&cnic_lock); + ulp_ops = rcu_dereference_protected(cp->ulp_ops[if_type], + lockdep_is held(&cnic_lock)); + if (!ulp_ops || !ulp_ops->indicate_netevent) { + mutex_unlock(&cnic_lock); continue; + } ctx = cp->ulp_handle[if_type]; + set_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]); + mutex_unlock(&cnic_lock); + ulp_ops->indicate_netevent(ctx, event, vlan_id); + + clear_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]); } - rcu_read_unlock(); } /* netdev event handler */