scsi: core: Introduce scsi_cmd_list_info()

Slightly improve code readability by introducing a helper function for
deriving the list information and by using guard() + return instead of
goto + explicit unlock + return.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240325224755.1477910-2-bvanassche@acm.orgSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_debugfs.c

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/seq_file.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_dbg.h>
@@ -32,31 +33,32 @@ static int scsi_flags_show(struct seq_file *m, const unsigned long flags,
 	return 0;
 }
 
-void scsi_show_rq(struct seq_file *m, struct request *rq)
+static const char *scsi_cmd_list_info(struct scsi_cmnd *cmd)
 {
-	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq), *cmd2;
 	struct Scsi_Host *shost = cmd->device->host;
+	struct scsi_cmnd *cmd2;
+
+	guard(spinlock_irq)(shost->host_lock);
+
+	list_for_each_entry(cmd2, &shost->eh_abort_list, eh_entry)
+		if (cmd == cmd2)
+			return "on eh_abort_list";
+
+	list_for_each_entry(cmd2, &shost->eh_cmd_q, eh_entry)
+		if (cmd == cmd2)
+			return "on eh_cmd_q";
+
+	return NULL;
+}
+
+void scsi_show_rq(struct seq_file *m, struct request *rq)
+{
+	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
 	int alloc_ms = jiffies_to_msecs(jiffies - cmd->jiffies_at_alloc);
 	int timeout_ms = jiffies_to_msecs(rq->timeout);
-	const char *list_info = NULL;
+	const char *list_info = scsi_cmd_list_info(cmd);
 	char buf[80] = "(?)";
 
-	spin_lock_irq(shost->host_lock);
-	list_for_each_entry(cmd2, &shost->eh_abort_list, eh_entry) {
-		if (cmd == cmd2) {
-			list_info = "on eh_abort_list";
-			goto unlock;
-		}
-	}
-	list_for_each_entry(cmd2, &shost->eh_cmd_q, eh_entry) {
-		if (cmd == cmd2) {
-			list_info = "on eh_cmd_q";
-			goto unlock;
-		}
-	}
-unlock:
-	spin_unlock_irq(shost->host_lock);
-
 	__scsi_format_command(buf, sizeof(buf), cmd->cmnd, cmd->cmd_len);
 	seq_printf(m, ", .cmd=%s, .retries=%d, .allowed=%d, .result = %#x, %s%s.flags=",
 		   buf, cmd->retries, cmd->allowed, cmd->result,