[PATCH 08/10] scsi_error: iterate over list of failed commands in scsi_eh_bus_device_reset()

[Hannes Reinecke <hare@suse.de>]

Iterating over all devices in scsi_eh_bus_device_reset() is
inefficient as not all devices may be affected during SCSI EH.
There also is no reason to open-code scsi_eh_test_devices()
as for FAST_IO_FAIL we really should just return the commands
without further ado.
So rewrite the loop in scsi_eh_bus_device_reset() to match the
loop in scsi_eh_target_reset() and scsi_eh_bus_reset().

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_error.c | 58 ++++++++++++++++++---------------------
 1 file changed, 27 insertions(+), 31 deletions(-)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 63b762d5d66f..7c655d08a305 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1570,54 +1570,50 @@ static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
 				    struct list_head *work_q,
 				    struct list_head *done_q)
 {
-	struct scsi_cmnd *scmd, *bdr_scmd, *next;
-	struct scsi_device *sdev;
-	enum scsi_disposition rtn;
+	struct scsi_cmnd *scmd, *next;
+	LIST_HEAD(tmp_list);
+	LIST_HEAD(check_list);
+
+	list_splice_init(work_q, &tmp_list);
+
+	while (!list_empty(&tmp_list)) {
+		struct scsi_device *sdev;
+		enum scsi_disposition rtn;
+
+		scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
+		sdev = scmd->device;
 
-	shost_for_each_device(sdev, shost) {
 		if (scsi_host_eh_past_deadline(shost)) {
+			/* push back on work queue for further processing */
+			list_splice_init(&check_list, work_q);
+			list_splice_init(&tmp_list, work_q);
 			SCSI_LOG_ERROR_RECOVERY(3,
 				sdev_printk(KERN_INFO, sdev,
 					    "%s: skip BDR, past eh deadline\n",
 					     current->comm));
-			scsi_device_put(sdev);
-			break;
+			return list_empty(work_q);
 		}
-		bdr_scmd = NULL;
-		list_for_each_entry(scmd, work_q, eh_entry)
-			if (scmd->device == sdev) {
-				bdr_scmd = scmd;
-				break;
-			}
-
-		if (!bdr_scmd)
-			continue;
-
 		SCSI_LOG_ERROR_RECOVERY(3,
 			sdev_printk(KERN_INFO, sdev,
 				     "%s: Sending BDR\n", current->comm));
 		rtn = scsi_try_bus_device_reset(sdev);
-		if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
-			if (!scsi_device_online(sdev) ||
-			    rtn == FAST_IO_FAIL ||
-			    !scsi_eh_tur(bdr_scmd)) {
-				list_for_each_entry_safe(scmd, next,
-							 work_q, eh_entry) {
-					if (scmd->device == sdev &&
-					    scsi_eh_action(scmd, rtn) != FAILED) {
-						set_host_byte(scmd, DID_RESET);
-						scsi_eh_finish_cmd(scmd, done_q);
-					}
-				}
-			}
-		} else {
+		if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
 			SCSI_LOG_ERROR_RECOVERY(3,
 				sdev_printk(KERN_INFO, sdev,
 					    "%s: BDR failed\n", current->comm));
+		list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
+			if (scmd->device != sdev)
+				continue;
+			if (rtn == SUCCESS)
+				list_move_tail(&scmd->eh_entry, &check_list);
+			else if (rtn == FAST_IO_FAIL) {
+				set_host_byte(scmd, DID_TRANSPORT_FAILFAST);
+				scsi_eh_finish_cmd(scmd, done_q);
+			}
 		}
 	}
 
-	return list_empty(work_q);
+	return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
 }
 
 /**
-- 
2.35.3