Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966379AbcCPI0e (ORCPT ); Wed, 16 Mar 2016 04:26:34 -0400 Received: from mail.kernel.org ([198.145.29.136]:60207 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965333AbcCPILP (ORCPT ); Wed, 16 Mar 2016 04:11:15 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, John Soni Jose , James Bottomley Subject: [PATCH 3.4 068/107] libiscsi: Fix host busy blocking during connection teardown Date: Wed, 16 Mar 2016 16:06:02 +0800 Message-Id: <1458115601-5762-68-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1458115541-5712-1-git-send-email-lizf@kernel.org> References: <1458115541-5712-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3472 Lines: 112 From: John Soni Jose 3.4.111-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit 660d0831d1494a6837b2f810d08b5be092c1f31d upstream. In case of hw iscsi offload, an host can have N-number of active connections. There can be IO's running on some connections which make host->host_busy always TRUE. Now if logout from a connection is tried then the code gets into an infinite loop as host->host_busy is always TRUE. iscsi_conn_teardown(....) { ......... /* * Block until all in-progress commands for this connection * time out or fail. */ for (;;) { spin_lock_irqsave(session->host->host_lock, flags); if (!atomic_read(&session->host->host_busy)) { /* OK for ERL == 0 */ spin_unlock_irqrestore(session->host->host_lock, flags); break; } spin_unlock_irqrestore(session->host->host_lock, flags); msleep_interruptible(500); iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): " "host_busy %d host_failed %d\n", atomic_read(&session->host->host_busy), session->host->host_failed); ................ ............... } } This is not an issue with software-iscsi/iser as each cxn is a separate host. Fix: Acquiring eh_mutex in iscsi_conn_teardown() before setting session->state = ISCSI_STATE_TERMINATE. Signed-off-by: John Soni Jose Reviewed-by: Mike Christie Reviewed-by: Chris Leech Signed-off-by: James Bottomley [lizf: Backported to 3.4: adjust context] Signed-of-by: Zefan Li --- drivers/scsi/libiscsi.c | 25 ++----------------------- 1 file changed, 2 insertions(+), 23 deletions(-) diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index 1243d2f..d9a898c 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -2907,10 +2907,10 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn) { struct iscsi_conn *conn = cls_conn->dd_data; struct iscsi_session *session = conn->session; - unsigned long flags; del_timer_sync(&conn->transport_timer); + mutex_lock(&session->eh_mutex); spin_lock_bh(&session->lock); conn->c_stage = ISCSI_CONN_CLEANUP_WAIT; if (session->leadconn == conn) { @@ -2922,28 +2922,6 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn) } spin_unlock_bh(&session->lock); - /* - * Block until all in-progress commands for this connection - * time out or fail. - */ - for (;;) { - spin_lock_irqsave(session->host->host_lock, flags); - if (!session->host->host_busy) { /* OK for ERL == 0 */ - spin_unlock_irqrestore(session->host->host_lock, flags); - break; - } - spin_unlock_irqrestore(session->host->host_lock, flags); - msleep_interruptible(500); - iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): " - "host_busy %d host_failed %d\n", - session->host->host_busy, - session->host->host_failed); - /* - * force eh_abort() to unblock - */ - wake_up(&conn->ehwait); - } - /* flush queued up work because we free the connection below */ iscsi_suspend_tx(conn); @@ -2956,6 +2934,7 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn) if (session->leadconn == conn) session->leadconn = NULL; spin_unlock_bh(&session->lock); + mutex_unlock(&session->eh_mutex); iscsi_destroy_conn(cls_conn); } -- 1.9.1