[PATCH] scsi: core: Report error list information in debugfs

[Bart Van Assche <bvanassche@acm.org>]

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).

Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi_debugfs.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/scsi_debugfs.c b/drivers/scsi/scsi_debugfs.c
index 217b70c678c3..a9bc5f7ce745 100644
--- a/drivers/scsi/scsi_debugfs.c
+++ b/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 +34,32 @@ 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";
+			break;
+		}
+	}
+	list_for_each_entry(cmd2, &shost->eh_cmd_q, eh_entry) {
+		if (cmd == cmd2) {
+			list_info = "on eh_cmd_q";
+			break;
+		}
+	}
+	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",