From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934731AbbJIAjw (ORCPT ); Thu, 8 Oct 2015 20:39:52 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35835 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934689AbbJIAjr (ORCPT ); Thu, 8 Oct 2015 20:39:47 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Mike Christie" , "Chris Leech" , "James Bottomley" , "John Soni Jose" Date: Fri, 09 Oct 2015 01:12:27 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 023/107] libiscsi: Fix host busy blocking during connection teardown In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.247 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: John Soni Jose 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 [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/scsi/libiscsi.c | 25 ++----------------------- 1 file changed, 2 insertions(+), 23 deletions(-) --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -2906,10 +2906,10 @@ void iscsi_conn_teardown(struct iscsi_cl { 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) { @@ -2921,28 +2921,6 @@ void iscsi_conn_teardown(struct iscsi_cl } 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); @@ -2955,6 +2933,7 @@ void iscsi_conn_teardown(struct iscsi_cl if (session->leadconn == conn) session->leadconn = NULL; spin_unlock_bh(&session->lock); + mutex_unlock(&session->eh_mutex); iscsi_destroy_conn(cls_conn); }