From mboxrd@z Thu Jan 1 00:00:00 1970 From: 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> References: <1401491923-5480-1-git-send-email-mchan@broadcom.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , Michael Chan To: Return-path: 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 In-Reply-To: <1401491923-5480-1-git-send-email-mchan@broadcom.com> Sender: netdev-owner@vger.kernel.org List-ID: 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 */ -- 1.7.1