[PATCH 09/10] scsi_error: map FAST_IO_FAIL to -EAGAIN in SCSI EH

[Hannes Reinecke <hare@xxxxxxx>]

Returning FAST_IO_FAIL from any of the SCSI EH functions is perfectly
valid, and indicates that the request could not be executed due to
the transport being busy.
But that is not an I/O error, and we should return -EAGAIN from
scsi_ioctl_reset() to correctly inform userspace.

Suggested-by: Benjamin Block <bblock@xxxxxxxxxxxxx>
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
 drivers/scsi/scsi_error.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 7c655d08a305..8e184d92abe9 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -2453,22 +2453,25 @@ scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
 		break;
 	case SG_SCSI_RESET_DEVICE:
 		rtn = scsi_try_bus_device_reset(dev);
-		if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
+		if (rtn == SUCCESS || rtn == FAST_IO_FAIL ||
+		    (val & SG_SCSI_RESET_NO_ESCALATE))
 			break;
 		fallthrough;
 	case SG_SCSI_RESET_TARGET:
 		rtn = scsi_try_target_reset(shost, starget);
-		if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
+		if (rtn == SUCCESS || rtn == FAST_IO_FAIL ||
+		    (val & SG_SCSI_RESET_NO_ESCALATE))
 			break;
 		fallthrough;
 	case SG_SCSI_RESET_BUS:
 		rtn = scsi_try_bus_reset(shost, dev->channel);
-		if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
+		if (rtn == SUCCESS || rtn == FAST_IO_FAIL ||
+		    (val & SG_SCSI_RESET_NO_ESCALATE))
 			break;
 		fallthrough;
 	case SG_SCSI_RESET_HOST:
 		rtn = scsi_try_host_reset(shost);
-		if (rtn == SUCCESS)
+		if (rtn == SUCCESS || rtn == FAST_IO_FAIL)
 			break;
 		fallthrough;
 	default:
@@ -2476,7 +2479,17 @@ scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
 		break;
 	}
 
-	error = (rtn == SUCCESS) ? 0 : -EIO;
+	switch (rtn) {
+	case SUCCESS:
+		error = 0;
+		break;
+	case FAST_IO_FAIL:
+		error = -EAGAIN;
+		break;
+	default:
+		error = -EIO;
+		break;
+	}
 
 	spin_lock_irqsave(shost->host_lock, flags);
 	shost->tmf_in_progress = 0;
-- 
2.35.3