From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759101AbbIVSNt (ORCPT ); Tue, 22 Sep 2015 14:13:49 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42834 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932595AbbIVRxw (ORCPT ); Tue, 22 Sep 2015 13:53:52 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: John Soni Jose , James Bottomley , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 058/102] libiscsi: Fix host busy blocking during connection teardown Date: Tue, 22 Sep 2015 10:51:54 -0700 Message-Id: <1442944358-1248-59-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1442944358-1248-1-git-send-email-kamal@canonical.com> References: <1442944358-1248-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt7 -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: Kamal Mostafa --- 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 8053f24..98d9bb6 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -2941,10 +2941,10 @@ 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->frwd_lock); conn->c_stage = ISCSI_CONN_CLEANUP_WAIT; if (session->leadconn == conn) { @@ -2956,28 +2956,6 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn) } 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_cls_conn *cls_conn) if (session->leadconn == conn) session->leadconn = NULL; spin_unlock_bh(&session->frwd_lock); + mutex_unlock(&session->eh_mutex); iscsi_destroy_conn(cls_conn); } -- 1.9.1