From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:54137 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754836AbbIKWum (ORCPT ); Fri, 11 Sep 2015 18:50:42 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, John Soni Jose , Mike Christie , Chris Leech , James Bottomley Subject: [PATCH 4.1 40/78] libiscsi: Fix host busy blocking during connection teardown Date: Fri, 11 Sep 2015 15:49:41 -0700 Message-Id: <20150911224612.020151017@linuxfoundation.org> In-Reply-To: <20150911224606.758437370@linuxfoundation.org> References: <20150911224606.758437370@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: stable-owner@vger.kernel.org List-ID: 4.1-stable 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 Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/libiscsi.c | 25 ++----------------------- 1 file changed, 2 insertions(+), 23 deletions(-) --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -2941,10 +2941,10 @@ 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->frwd_lock); conn->c_stage = ISCSI_CONN_CLEANUP_WAIT; if (session->leadconn == conn) { @@ -2956,28 +2956,6 @@ void iscsi_conn_teardown(struct iscsi_cl } spin_unlock_bh(&session->frwd_lock); - /* - * 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); - /* - * force eh_abort() to unblock - */ - wake_up(&conn->ehwait); - } - /* flush queued up work because we free the connection below */ iscsi_suspend_tx(conn); @@ -2994,6 +2972,7 @@ void iscsi_conn_teardown(struct iscsi_cl if (session->leadconn == conn) session->leadconn = NULL; spin_unlock_bh(&session->frwd_lock); + mutex_unlock(&session->eh_mutex); iscsi_destroy_conn(cls_conn); }