iscsi changes for 2.6.38

iscsi changes for 2.6.38

[michaelc]

These patches are for 2.6.38. They were made over scsi-rc-fixes.
They fix a couple bugs and remove the host lock from the queuecommand
path.

[PATCH 1/5] libiscsi: add more informative failure message during iscsi scsi eh
[PATCH 2/5] be2iscsi: fix gfp use in alloc_pdu
[PATCH 3/5] be2iscsi: fix null ptr when accessing task hdr
[PATCH 4/5] libiscsi: do not take host lock in queuecommand
[PATCH 5/5] libiscsi: use bh locking instead of irq with session lock

[PATCH 1/5] libiscsi: add more informative failure message during iscsi scsi eh

[michaelc]

From: Mike Christie <michaelc@cs.wisc.edu>

This adds a more informative error code and message
for the iscsi scsi eh session drop paths. This allows
you to distinguish if the session was dropped due to
a connection failure vs the iscsi layer dropping
the session due to scsi eh failure processing.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
---
 drivers/scsi/libiscsi.c |   10 +++++-----
 include/scsi/iscsi_if.h |    1 +
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index c15fde8..434d9ae 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1795,9 +1795,9 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
 				      NULL, 0);
 	if (!task) {
 		spin_unlock_bh(&session->lock);
+		iscsi_conn_printk(KERN_ERR, conn, "Could not send TMF.\n");
 		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
 		spin_lock_bh(&session->lock);
-		ISCSI_DBG_EH(session, "tmf exec failure\n");
 		return -EPERM;
 	}
 	conn->tmfcmd_pdus_cnt++;
@@ -2202,7 +2202,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
 		goto success_unlocked;
 	case TMF_TIMEDOUT:
 		spin_unlock_bh(&session->lock);
-		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+		iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
 		goto failed_unlocked;
 	case TMF_NOT_FOUND:
 		if (!sc->SCp.ptr) {
@@ -2289,7 +2289,7 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc)
 		break;
 	case TMF_TIMEDOUT:
 		spin_unlock_bh(&session->lock);
-		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+		iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
 		goto done;
 	default:
 		conn->tmf_state = TMF_INITIAL;
@@ -2370,7 +2370,7 @@ failed:
 	 * we drop the lock here but the leadconn cannot be destoyed while
 	 * we are in the scsi eh
 	 */
-	iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+	iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
 
 	ISCSI_DBG_EH(session, "wait for relogin\n");
 	wait_event_interruptible(conn->ehwait,
@@ -2452,7 +2452,7 @@ int iscsi_eh_target_reset(struct scsi_cmnd *sc)
 		break;
 	case TMF_TIMEDOUT:
 		spin_unlock_bh(&session->lock);
-		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+		iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
 		goto done;
 	default:
 		conn->tmf_state = TMF_INITIAL;
diff --git a/include/scsi/iscsi_if.h b/include/scsi/iscsi_if.h
index a8631ac..c3e1cbc 100644
--- a/include/scsi/iscsi_if.h
+++ b/include/scsi/iscsi_if.h
@@ -263,6 +263,7 @@ enum iscsi_err {
 	ISCSI_ERR_INVALID_HOST		= ISCSI_ERR_BASE + 18,
 	ISCSI_ERR_XMIT_FAILED		= ISCSI_ERR_BASE + 19,
 	ISCSI_ERR_TCP_CONN_CLOSE	= ISCSI_ERR_BASE + 20,
+	ISCSI_ERR_SCSI_EH_SESSION_RST	= ISCSI_ERR_BASE + 21,
 };
 
 /*
-- 
1.7.0.1

[PATCH 2/5] be2iscsi: fix gfp use in alloc_pdu

[michaelc]

From: Mike Christie <michaelc@cs.wisc.edu>

The pdu allication callout is called from a spin lock
and in the IO path so we cannot use GFP_KERNEL. This
has the driver use GFP_ATOMIC.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
---
 drivers/scsi/be2iscsi/be_main.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
index 75a85aa..be07ca0 100644
--- a/drivers/scsi/be2iscsi/be_main.c
+++ b/drivers/scsi/be2iscsi/be_main.c
@@ -3785,7 +3785,7 @@ static int beiscsi_alloc_pdu(struct iscsi_task *task, uint8_t opcode)
 	dma_addr_t paddr;
 
 	io_task->cmd_bhs = pci_pool_alloc(beiscsi_sess->bhs_pool,
-					  GFP_KERNEL, &paddr);
+					  GFP_ATOMIC, &paddr);
 	if (!io_task->cmd_bhs)
 		return -ENOMEM;
 	io_task->bhs_pa.u.a64.address = paddr;
-- 
1.7.0.1

[PATCH 3/5] be2iscsi: fix null ptr when accessing task hdr

[michaelc]

From: Mike Christie <michaelc@cs.wisc.edu>

If alloc_pdu fails then the task->hdr pointer may not be
set. This adds a check for this case in the cleanup callback.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
---
 drivers/scsi/be2iscsi/be_main.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
index be07ca0..79cefbe 100644
--- a/drivers/scsi/be2iscsi/be_main.c
+++ b/drivers/scsi/be2iscsi/be_main.c
@@ -3914,7 +3914,8 @@ static void beiscsi_cleanup_task(struct iscsi_task *task)
 			io_task->psgl_handle = NULL;
 		}
 	} else {
-		if ((task->hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGIN)
+		if (task->hdr &&
+		   ((task->hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGIN))
 			return;
 		if (io_task->psgl_handle) {
 			spin_lock(&phba->mgmt_sgl_lock);
-- 
1.7.0.1

[PATCH 4/5] libiscsi: do not take host lock in queuecommand

[michaelc]

From: Mike Christie <michaelc@cs.wisc.edu>

iscsi_tcp, ib_iser, cxgb*, be2iscsi and bnx2i do not use
the host lock and do not take the session lock against
a irq, so this patch drops the DEF_SCSI_QCMD use. Instead
we just take the session lock and disable bhs.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
---
 drivers/scsi/libiscsi.c |   37 ++++++++++++++-----------------------
 include/scsi/libiscsi.h |    3 ++-
 2 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 434d9ae..f460637 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -505,6 +505,7 @@ static void iscsi_free_task(struct iscsi_task *task)
 	struct iscsi_conn *conn = task->conn;
 	struct iscsi_session *session = conn->session;
 	struct scsi_cmnd *sc = task->sc;
+	int oldstate = task->state;
 
 	ISCSI_DBG_SESSION(session, "freeing task itt 0x%x state %d sc %p\n",
 			  task->itt, task->state, task->sc);
@@ -525,10 +526,10 @@ static void iscsi_free_task(struct iscsi_task *task)
 		/* SCSI eh reuses commands to verify us */
 		sc->SCp.ptr = NULL;
 		/*
-		 * queue command may call this to free the task, but
-		 * not have setup the sc callback
+		 * queue command may call this to free the task, so
+		 * it will decide how to return sc to scsi-ml.
 		 */
-		if (sc->scsi_done)
+		if (oldstate != ISCSI_TASK_REQUEUE_SCSIQ)
 			sc->scsi_done(sc);
 	}
 }
@@ -571,7 +572,8 @@ static void iscsi_complete_task(struct iscsi_task *task, int state)
 			  task->itt, task->state, task->sc);
 	if (task->state == ISCSI_TASK_COMPLETED ||
 	    task->state == ISCSI_TASK_ABRT_TMF ||
-	    task->state == ISCSI_TASK_ABRT_SESS_RECOV)
+	    task->state == ISCSI_TASK_ABRT_SESS_RECOV ||
+	    task->state == ISCSI_TASK_REQUEUE_SCSIQ)
 		return;
 	WARN_ON_ONCE(task->state == ISCSI_TASK_FREE);
 	task->state = state;
@@ -1599,27 +1601,23 @@ enum {
 	FAILURE_SESSION_NOT_READY,
 };
 
-static int iscsi_queuecommand_lck(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
+int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
 {
 	struct iscsi_cls_session *cls_session;
-	struct Scsi_Host *host;
 	struct iscsi_host *ihost;
 	int reason = 0;
 	struct iscsi_session *session;
 	struct iscsi_conn *conn;
 	struct iscsi_task *task = NULL;
 
-	sc->scsi_done = done;
 	sc->result = 0;
 	sc->SCp.ptr = NULL;
 
-	host = sc->device->host;
 	ihost = shost_priv(host);
-	spin_unlock(host->host_lock);
 
 	cls_session = starget_to_session(scsi_target(sc->device));
 	session = cls_session->dd_data;
-	spin_lock(&session->lock);
+	spin_lock_bh(&session->lock);
 
 	reason = iscsi_session_chkready(cls_session);
 	if (reason) {
@@ -1705,25 +1703,21 @@ static int iscsi_queuecommand_lck(struct scsi_cmnd *sc, void (*done)(struct scsi
 	}
 
 	session->queued_cmdsn++;
-	spin_unlock(&session->lock);
-	spin_lock(host->host_lock);
+	spin_unlock_bh(&session->lock);
 	return 0;
 
 prepd_reject:
-	sc->scsi_done = NULL;
-	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
+	iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ);
 reject:
-	spin_unlock(&session->lock);
+	spin_unlock_bh(&session->lock);
 	ISCSI_DBG_SESSION(session, "cmd 0x%x rejected (%d)\n",
 			  sc->cmnd[0], reason);
-	spin_lock(host->host_lock);
 	return SCSI_MLQUEUE_TARGET_BUSY;
 
 prepd_fault:
-	sc->scsi_done = NULL;
-	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
+	iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ);
 fault:
-	spin_unlock(&session->lock);
+	spin_unlock_bh(&session->lock);
 	ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n",
 			  sc->cmnd[0], reason);
 	if (!scsi_bidi_cmnd(sc))
@@ -1732,12 +1726,9 @@ fault:
 		scsi_out(sc)->resid = scsi_out(sc)->length;
 		scsi_in(sc)->resid = scsi_in(sc)->length;
 	}
-	done(sc);
-	spin_lock(host->host_lock);
+	sc->scsi_done(sc);
 	return 0;
 }
-
-DEF_SCSI_QCMD(iscsi_queuecommand)
 EXPORT_SYMBOL_GPL(iscsi_queuecommand);
 
 int iscsi_change_queue_depth(struct scsi_device *sdev, int depth, int reason)
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index b81d969..f1ff600 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -89,6 +89,7 @@ enum {
 	ISCSI_TASK_RUNNING,
 	ISCSI_TASK_ABRT_TMF,		/* aborted due to TMF */
 	ISCSI_TASK_ABRT_SESS_RECOV,	/* aborted due to session recovery */
+	ISCSI_TASK_REQUEUE_SCSIQ,	/* qcmd requeueing to scsi-ml */
 };
 
 struct iscsi_r2t_info {
@@ -341,7 +342,7 @@ extern int iscsi_eh_abort(struct scsi_cmnd *sc);
 extern int iscsi_eh_recover_target(struct scsi_cmnd *sc);
 extern int iscsi_eh_session_reset(struct scsi_cmnd *sc);
 extern int iscsi_eh_device_reset(struct scsi_cmnd *sc);
-extern int iscsi_queuecommand(struct Scsi_Host *h, struct scsi_cmnd *sc);
+extern int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc);
 
 /*
  * iSCSI host helpers.
-- 
1.7.0.1

[PATCH 5/5] libiscsi: use bh locking instead of irq with session lock

[michaelc]

From: Mike Christie <michaelc@cs.wisc.edu>

The session lock is taken in threads, timers, and bottom halves
like softirqs and tasklets. All the code but
iscsi_conn/session_failure take the session lock with the spin_lock_bh
call. This was done because I thought some offload drivers
would be calling these functions from a irq. They never did,
so this patch has iscsi_conn/session_failure use the bh
locking.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
---
 drivers/scsi/libiscsi.c |   14 ++++++--------
 1 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index f460637..b0481a8 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1337,17 +1337,16 @@ void iscsi_session_failure(struct iscsi_session *session,
 {
 	struct iscsi_conn *conn;
 	struct device *dev;
-	unsigned long flags;
 
-	spin_lock_irqsave(&session->lock, flags);
+	spin_lock_bh(&session->lock);
 	conn = session->leadconn;
 	if (session->state == ISCSI_STATE_TERMINATE || !conn) {
-		spin_unlock_irqrestore(&session->lock, flags);
+		spin_unlock_bh(&session->lock);
 		return;
 	}
 
 	dev = get_device(&conn->cls_conn->dev);
-	spin_unlock_irqrestore(&session->lock, flags);
+	spin_unlock_bh(&session->lock);
 	if (!dev)
 	        return;
 	/*
@@ -1366,17 +1365,16 @@ EXPORT_SYMBOL_GPL(iscsi_session_failure);
 void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
 {
 	struct iscsi_session *session = conn->session;
-	unsigned long flags;
 
-	spin_lock_irqsave(&session->lock, flags);
+	spin_lock_bh(&session->lock);
 	if (session->state == ISCSI_STATE_FAILED) {
-		spin_unlock_irqrestore(&session->lock, flags);
+		spin_unlock_bh(&session->lock);
 		return;
 	}
 
 	if (conn->stop_stage == 0)
 		session->state = ISCSI_STATE_FAILED;
-	spin_unlock_irqrestore(&session->lock, flags);
+	spin_unlock_bh(&session->lock);
 
 	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
 	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
-- 
1.7.0.1