From: Julian Wiedmann <jwi@linux.ibm.com>
Date: Thu, 10 Sep 2020 21:49:15 +0200
Subject: scsi: zfcp: Use list_first_entry_or_null() in zfcp_erp_thread()
Git-commit: addf1372961523cc8cb7ab4ee26d5e1373bf64a0
Patch-mainline: v5.10-rc1
References: jsc#SLE-15871 bsc#1176961 LTC#187760

Use the right helper to avoid poking around in the list's internals.

Link: https://lore.kernel.org/r/ed669555c73aab95b29444c10066f492c0c43391.1599765652.git.bblock@linux.ibm.com
Reviewed-by: Steffen Maier <maier@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/s390/scsi/zfcp_erp.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -1607,7 +1607,6 @@ check_target:
 static int zfcp_erp_thread(void *data)
 {
 	struct zfcp_adapter *adapter = (struct zfcp_adapter *) data;
-	struct list_head *next;
 	struct zfcp_erp_action *act;
 	unsigned long flags;
 
@@ -1620,12 +1619,11 @@ static int zfcp_erp_thread(void *data)
 			break;
 
 		write_lock_irqsave(&adapter->erp_lock, flags);
-		next = adapter->erp_ready_head.next;
+		act = list_first_entry_or_null(&adapter->erp_ready_head,
+					       struct zfcp_erp_action, list);
 		write_unlock_irqrestore(&adapter->erp_lock, flags);
 
-		if (next != &adapter->erp_ready_head) {
-			act = list_entry(next, struct zfcp_erp_action, list);
-
+		if (act) {
 			/* there is more to come after dismission, no notify */
 			if (zfcp_erp_strategy(act) != ZFCP_ERP_DISMISSED)
 				zfcp_erp_wakeup(adapter);