scsi: core: Report error list information in debugfs

Provide information in debugfs about SCSI error handling to make it easier
to debug the SCSI error handler. Additionally, report the maximum number of
retries in debugfs (.allowed).

Reviewed-by: John Garry <john.g.garry@oracle.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230822163811.219569-1-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: bvanassche

drivers/scsi/scsi_debugfs.c

@@ -3,6 +3,7 @@
 #include <linux/seq_file.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_dbg.h>
+#include <scsi/scsi_host.h>
 #include "scsi_debugfs.h"
 
 #define SCSI_CMD_FLAG_NAME(name)[const_ilog2(SCMD_##name)] = #name
@@ -33,14 +34,33 @@ static int scsi_flags_show(struct seq_file *m, const unsigned long flags,
 
 void scsi_show_rq(struct seq_file *m, struct request *rq)
 {
-	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq), *cmd2;
+	struct Scsi_Host *shost = cmd->device->host;
 	int alloc_ms = jiffies_to_msecs(jiffies - cmd->jiffies_at_alloc);
 	int timeout_ms = jiffies_to_msecs(rq->timeout);
+	const char *list_info = NULL;
 	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, .result = %#x, .flags=", buf,
-		   cmd->retries, cmd->result);
+	seq_printf(m, ", .cmd=%s, .retries=%d, .allowed=%d, .result = %#x, %s%s.flags=",
+		   buf, cmd->retries, cmd->allowed, cmd->result,
+		   list_info ? : "", list_info ? ", " : "");
 	scsi_flags_show(m, cmd->flags, scsi_cmd_flags,
 			ARRAY_SIZE(scsi_cmd_flags));
 	seq_printf(m, ", .timeout=%d.%03d, allocated %d.%03d s ago",