[SCSI] zfcp: Use kthread API for zfcp erp thread

Switch the creation of the zfcp erp thread from the deprecated
kernel_thread API to the kthread API. This allows also the removal of
some flags in zfcp since the kthread API handles thread creation and
shutdown internally. To allow the usage of the kthread_stop function,
replace the erp ready semaphore with a waitqueue for waiting until erp
actions arrive on the ready queue.

Reviewed-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 24 insertions, 38 deletions

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index 373567eda8f6..577e15708598 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -9,6 +9,7 @@
 #define KMSG_COMPONENT "zfcp"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
+#include <linux/kthread.h>
 #include "zfcp_ext.h"
 
 #define ZFCP_MAX_ERPS                   3
@@ -75,7 +76,7 @@ static void zfcp_erp_action_ready(struct zfcp_erp_action *act)
 
 	list_move(&act->list, &act->adapter->erp_ready_head);
 	zfcp_dbf_rec_action("erardy1", act);
-	up(&adapter->erp_ready_sem);
+	wake_up(&adapter->erp_ready_wq);
 	zfcp_dbf_rec_thread("erardy2", adapter->dbf);
 }
 
@@ -212,8 +213,7 @@ static int zfcp_erp_action_enqueue(int want, struct zfcp_adapter *adapter,
 	int retval = 1, need;
 	struct zfcp_erp_action *act = NULL;
 
-	if (!(atomic_read(&adapter->status) &
-	      ZFCP_STATUS_ADAPTER_ERP_THREAD_UP))
+	if (!adapter->erp_thread)
 		return -EIO;
 
 	need = zfcp_erp_required_act(want, adapter, port, unit);
@@ -226,7 +226,7 @@ static int zfcp_erp_action_enqueue(int want, struct zfcp_adapter *adapter,
 		goto out;
 	++adapter->erp_total_count;
 	list_add_tail(&act->list, &adapter->erp_ready_head);
-	up(&adapter->erp_ready_sem);
+	wake_up(&adapter->erp_ready_wq);
 	zfcp_dbf_rec_thread("eracte1", adapter->dbf);
 	retval = 0;
  out:
@@ -641,7 +641,8 @@ static int zfcp_erp_adapter_strat_fsf_xconf(struct zfcp_erp_action *erp_action)
 		}
 
 		zfcp_dbf_rec_thread_lock("erasfx1", adapter->dbf);
-		down(&adapter->erp_ready_sem);
+		wait_event(adapter->erp_ready_wq,
+			   !list_empty(&adapter->erp_ready_head));
 		zfcp_dbf_rec_thread_lock("erasfx2", adapter->dbf);
 		if (erp_action->status & ZFCP_STATUS_ERP_TIMEDOUT)
 			break;
@@ -682,7 +683,8 @@ static int zfcp_erp_adapter_strategy_open_fsf_xport(struct zfcp_erp_action *act)
 		return ZFCP_ERP_FAILED;
 
 	zfcp_dbf_rec_thread_lock("erasox1", adapter->dbf);
-	down(&adapter->erp_ready_sem);
+	wait_event(adapter->erp_ready_wq,
+		   !list_empty(&adapter->erp_ready_head));
 	zfcp_dbf_rec_thread_lock("erasox2", adapter->dbf);
 	if (act->status & ZFCP_STATUS_ERP_TIMEDOUT)
 		return ZFCP_ERP_FAILED;
@@ -1285,21 +1287,17 @@ static int zfcp_erp_thread(void *data)
 	struct list_head *next;
 	struct zfcp_erp_action *act;
 	unsigned long flags;
-	int ignore;
-
-	daemonize("zfcperp%s", dev_name(&adapter->ccw_device->dev));
-	/* Block all signals */
-	siginitsetinv(&current->blocked, 0);
-	atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP, &adapter->status);
-	wake_up(&adapter->erp_thread_wqh);
-
-	while (!(atomic_read(&adapter->status) &
-		 ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL)) {
 
+	for (;;) {
 		zfcp_dbf_rec_thread_lock("erthrd1", adapter->dbf);
-		ignore = down_interruptible(&adapter->erp_ready_sem);
+		wait_event_interruptible(adapter->erp_ready_wq,
+			   !list_empty(&adapter->erp_ready_head) ||
+			   kthread_should_stop());
 		zfcp_dbf_rec_thread_lock("erthrd2", adapter->dbf);
 
+		if (kthread_should_stop())
+			break;
+
 		write_lock_irqsave(&adapter->erp_lock, flags);
 		next = adapter->erp_ready_head.next;
 		write_unlock_irqrestore(&adapter->erp_lock, flags);
@@ -1313,9 +1311,6 @@ static int zfcp_erp_thread(void *data)
 		}
 	}
 
-	atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP, &adapter->status);
-	wake_up(&adapter->erp_thread_wqh);
-
 	return 0;
 }
 
@@ -1327,18 +1322,17 @@ static int zfcp_erp_thread(void *data)
  */
 int zfcp_erp_thread_setup(struct zfcp_adapter *adapter)
 {
-	int retval;
+	struct task_struct *thread;
 
-	atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_UP, &adapter->status);
-	retval = kernel_thread(zfcp_erp_thread, adapter, SIGCHLD);
-	if (retval < 0) {
+	thread = kthread_run(zfcp_erp_thread, adapter, "zfcperp%s",
+			     dev_name(&adapter->ccw_device->dev));
+	if (IS_ERR(thread)) {
 		dev_err(&adapter->ccw_device->dev,
 			"Creating an ERP thread for the FCP device failed.\n");
-		return retval;
+		return PTR_ERR(thread);
 	}
-	wait_event(adapter->erp_thread_wqh,
-		   atomic_read(&adapter->status) &
-			ZFCP_STATUS_ADAPTER_ERP_THREAD_UP);
+
+	adapter->erp_thread = thread;
 	return 0;
 }
 
@@ -1353,16 +1347,8 @@ int zfcp_erp_thread_setup(struct zfcp_adapter *adapter)
  */
 void zfcp_erp_thread_kill(struct zfcp_adapter *adapter)
 {
-	atomic_set_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL, &adapter->status);
-	up(&adapter->erp_ready_sem);
-	zfcp_dbf_rec_thread_lock("erthrk1", adapter->dbf);
-
-	wait_event(adapter->erp_thread_wqh,
-		   !(atomic_read(&adapter->status) &
-				ZFCP_STATUS_ADAPTER_ERP_THREAD_UP));
-
-	atomic_clear_mask(ZFCP_STATUS_ADAPTER_ERP_THREAD_KILL,
-			  &adapter->status);
+	kthread_stop(adapter->erp_thread);
+	adapter->erp_thread = NULL;
 }
 
 /**