From dea5f0998aa82bdeca260b87c653db11e91329b2 Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Wed, 31 Oct 2012 22:04:26 -0700
Subject: [PATCH 1/5] target: Re-add explict zeroing of INQUIRY bounce buffer
 memory

This patch fixes a regression in spc_emulate_inquiry() code where the
local scope bounce buffer was no longer getting it's memory zeroed,
causing various problems with SCSI initiators that depend upon areas
of INQUIRY EVPD=0x83 payload having been zeroed.

This bug was introduced with the following v3.7-rc1 patch + CC'ed
stable commit:

commit ffe7b0e9326d9c68f5688bef691dd49f1e0d3651
Author: Paolo Bonzini <pbonzini@redhat.com>
Date:   Fri Sep 7 17:30:38 2012 +0200

    target: support zero allocation length in INQUIRY

Go ahead and re-add the missing memset of bounce buffer memory to be
copied into the outgoing se_cmd descriptor kmapped SGL payload.

Reported-by: Kelsey Prantis <kelsey.prantis@intel.com>
Cc: Kelsey Prantis <kelsey.prantis@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Grover <agrover@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/target/target_core_spc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index 9229bd9ad61b..6fd434d3d7e4 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -605,6 +605,8 @@ static int spc_emulate_inquiry(struct se_cmd *cmd)
 	unsigned char buf[SE_INQUIRY_BUF];
 	int p, ret;
 
+	memset(buf, 0, SE_INQUIRY_BUF);
+
 	if (dev == tpg->tpg_virt_lun0.lun_se_dev)
 		buf[0] = 0x3f; /* Not connected */
 	else

From 0d0f9dfb31e0a6c92063e235417b42df185b3275 Mon Sep 17 00:00:00 2001
From: Roland Dreier <roland@purestorage.com>
Date: Wed, 31 Oct 2012 09:16:44 -0700
Subject: [PATCH 2/5] target: Don't return success from module_init() if setup
 fails

If the call to core_dev_release_virtual_lun0() fails, then nothing
sets ret to anything other than 0, so even though everything is
torn down and freed, target_core_init_configfs() will seem to succeed
and the module will be loaded.  Fix this by passing the return value
on up the chain.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/target/target_core_configfs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 015f5be27bf6..c123327499a3 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -3206,7 +3206,8 @@ static int __init target_core_init_configfs(void)
 	if (ret < 0)
 		goto out;
 
-	if (core_dev_setup_virtual_lun0() < 0)
+	ret = core_dev_setup_virtual_lun0();
+	if (ret < 0)
 		goto out;
 
 	return 0;

From 3e03989b5868acf69a391a424dc71fcd6cc48167 Mon Sep 17 00:00:00 2001
From: Roland Dreier <roland@purestorage.com>
Date: Wed, 31 Oct 2012 09:16:45 -0700
Subject: [PATCH 3/5] target: Avoid integer overflow in
 se_dev_align_max_sectors()

The expression (max_sectors * block_size) might overflow a u32
(indeed, since iblock sets max_hw_sectors to UINT_MAX, it is
guaranteed to overflow and end up with a much-too-small result in many
common cases).  Fix this by doing an equivalent calculation that
doesn't require multiplication.

While we're touching this code, avoid splitting a printk format across
two lines and use pr_info(...) instead of printk(KERN_INFO ...).

Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/target/target_core_device.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 8d774da16320..9abef9f8eb76 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -850,20 +850,20 @@ int se_dev_check_shutdown(struct se_device *dev)
 
 static u32 se_dev_align_max_sectors(u32 max_sectors, u32 block_size)
 {
-	u32 tmp, aligned_max_sectors;
+	u32 aligned_max_sectors;
+	u32 alignment;
 	/*
 	 * Limit max_sectors to a PAGE_SIZE aligned value for modern
 	 * transport_allocate_data_tasks() operation.
 	 */
-	tmp = rounddown((max_sectors * block_size), PAGE_SIZE);
-	aligned_max_sectors = (tmp / block_size);
-	if (max_sectors != aligned_max_sectors) {
-		printk(KERN_INFO "Rounding down aligned max_sectors from %u"
-				" to %u\n", max_sectors, aligned_max_sectors);
-		return aligned_max_sectors;
-	}
+	alignment = max(1ul, PAGE_SIZE / block_size);
+	aligned_max_sectors = rounddown(max_sectors, alignment);
 
-	return max_sectors;
+	if (max_sectors != aligned_max_sectors)
+		pr_info("Rounding down aligned max_sectors from %u to %u\n",
+			max_sectors, aligned_max_sectors);
+
+	return aligned_max_sectors;
 }
 
 void se_dev_set_default_attribs(

From d5627acba9ae584cf4928af19f7ddf5f6837de32 Mon Sep 17 00:00:00 2001
From: Roland Dreier <roland@purestorage.com>
Date: Wed, 31 Oct 2012 09:16:46 -0700
Subject: [PATCH 4/5] iscsi-target: Fix missed wakeup race in TX thread

The sleeping code in iscsi_target_tx_thread() is susceptible to the classic
missed wakeup race:

 - TX thread finishes handle_immediate_queue() and handle_response_queue(),
   thinks both queues are empty.
 - Another thread adds a queue entry and does wake_up_process(), which does
   nothing because the TX thread is still awake.
 - TX thread does schedule_timeout() and sleeps forever.

In practice this can kill an iSCSI connection if for example an initiator
does single-threaded writes and the target misses the wakeup window when
queueing an R2T; in this case the connection will be stuck until the
initiator loses patience and does some task management operation (or kills
the connection entirely).

Fix this by converting to wait_event_interruptible(), which does not
suffer from this sort of race.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: Andy Grover <agrover@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/target/iscsi/iscsi_target.c       |  4 +++-
 drivers/target/iscsi/iscsi_target_core.h  |  1 +
 drivers/target/iscsi/iscsi_target_login.c |  1 +
 drivers/target/iscsi/iscsi_target_util.c  | 22 ++++++++++++++++++++--
 drivers/target/iscsi/iscsi_target_util.h  |  1 +
 5 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index d6ce2182e672..035c2c762537 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -3719,7 +3719,9 @@ int iscsi_target_tx_thread(void *arg)
 		 */
 		iscsit_thread_check_cpumask(conn, current, 1);
 
-		schedule_timeout_interruptible(MAX_SCHEDULE_TIMEOUT);
+		wait_event_interruptible(conn->queues_wq,
+					 !iscsit_conn_all_queues_empty(conn) ||
+					 ts->status == ISCSI_THREAD_SET_RESET);
 
 		if ((ts->status == ISCSI_THREAD_SET_RESET) ||
 		     signal_pending(current))
diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h
index 2ba9f9b9435c..21048dbf7d13 100644
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -486,6 +486,7 @@ struct iscsi_tmr_req {
 };
 
 struct iscsi_conn {
+	wait_queue_head_t	queues_wq;
 	/* Authentication Successful for this connection */
 	u8			auth_complete;
 	/* State connection is currently in */
diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index cdc8a10939c3..f8dbec05d5e5 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -41,6 +41,7 @@
 
 static int iscsi_login_init_conn(struct iscsi_conn *conn)
 {
+	init_waitqueue_head(&conn->queues_wq);
 	INIT_LIST_HEAD(&conn->conn_list);
 	INIT_LIST_HEAD(&conn->conn_cmd_list);
 	INIT_LIST_HEAD(&conn->immed_queue_list);
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index afd98ccd40ae..1a91195ab619 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -488,7 +488,7 @@ void iscsit_add_cmd_to_immediate_queue(
 	atomic_set(&conn->check_immediate_queue, 1);
 	spin_unlock_bh(&conn->immed_queue_lock);
 
-	wake_up_process(conn->thread_set->tx_thread);
+	wake_up(&conn->queues_wq);
 }
 
 struct iscsi_queue_req *iscsit_get_cmd_from_immediate_queue(struct iscsi_conn *conn)
@@ -562,7 +562,7 @@ void iscsit_add_cmd_to_response_queue(
 	atomic_inc(&cmd->response_queue_count);
 	spin_unlock_bh(&conn->response_queue_lock);
 
-	wake_up_process(conn->thread_set->tx_thread);
+	wake_up(&conn->queues_wq);
 }
 
 struct iscsi_queue_req *iscsit_get_cmd_from_response_queue(struct iscsi_conn *conn)
@@ -616,6 +616,24 @@ static void iscsit_remove_cmd_from_response_queue(
 	}
 }
 
+bool iscsit_conn_all_queues_empty(struct iscsi_conn *conn)
+{
+	bool empty;
+
+	spin_lock_bh(&conn->immed_queue_lock);
+	empty = list_empty(&conn->immed_queue_list);
+	spin_unlock_bh(&conn->immed_queue_lock);
+
+	if (!empty)
+		return empty;
+
+	spin_lock_bh(&conn->response_queue_lock);
+	empty = list_empty(&conn->response_queue_list);
+	spin_unlock_bh(&conn->response_queue_lock);
+
+	return empty;
+}
+
 void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *conn)
 {
 	struct iscsi_queue_req *qr, *qr_tmp;
diff --git a/drivers/target/iscsi/iscsi_target_util.h b/drivers/target/iscsi/iscsi_target_util.h
index 44054bd35437..894d0f837924 100644
--- a/drivers/target/iscsi/iscsi_target_util.h
+++ b/drivers/target/iscsi/iscsi_target_util.h
@@ -25,6 +25,7 @@ extern struct iscsi_queue_req *iscsit_get_cmd_from_immediate_queue(struct iscsi_
 extern void iscsit_add_cmd_to_response_queue(struct iscsi_cmd *, struct iscsi_conn *, u8);
 extern struct iscsi_queue_req *iscsit_get_cmd_from_response_queue(struct iscsi_conn *);
 extern void iscsit_remove_cmd_from_tx_queues(struct iscsi_cmd *, struct iscsi_conn *);
+extern bool iscsit_conn_all_queues_empty(struct iscsi_conn *);
 extern void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *);
 extern void iscsit_release_cmd(struct iscsi_cmd *);
 extern void iscsit_free_cmd(struct iscsi_cmd *);

From ab74b3d62f05192bf8fb8f169e7999d1183b2e08 Mon Sep 17 00:00:00 2001
From: Steve Hodgson <steve@purestorage.com>
Date: Wed, 31 Oct 2012 10:24:02 -0700
Subject: [PATCH 5/5] target: Fix incorrect usage of nested IRQ spinlocks in
 ABORT_TASK path

This patch changes core_tmr_abort_task() to use spin_lock -> spin_unlock
around se_cmd->t_state_lock while spin_lock_irqsave is held via
se_sess->sess_cmd_lock.

Signed-off-by: Steve Hodgson <steve@purestorage.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/target/target_core_tmr.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 1c59a3c23b2c..be75c4331a92 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -140,15 +140,15 @@ void core_tmr_abort_task(
 		printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
 			se_cmd->se_tfo->get_fabric_name(), ref_tag);
 
-		spin_lock_irq(&se_cmd->t_state_lock);
+		spin_lock(&se_cmd->t_state_lock);
 		if (se_cmd->transport_state & CMD_T_COMPLETE) {
 			printk("ABORT_TASK: ref_tag: %u already complete, skipping\n", ref_tag);
-			spin_unlock_irq(&se_cmd->t_state_lock);
+			spin_unlock(&se_cmd->t_state_lock);
 			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 			goto out;
 		}
 		se_cmd->transport_state |= CMD_T_ABORTED;
-		spin_unlock_irq(&se_cmd->t_state_lock);
+		spin_unlock(&se_cmd->t_state_lock);
 
 		list_del_init(&se_cmd->se_cmd_list);
 		kref_get(&se_cmd->cmd_kref);