[PATCH 2/5] SCSI:sd:error handling in sd_sync_cache()

[Oliver Neukum]

The SCSI commands sd_sync_cache() uses may fail.
These errors needs to be evaluated to return correct
error codes. This fixes system suspension while a device
removal is being handled.

Signed-off-by: Oliver NEukum <oneukum@xxxxxxx>
---
 drivers/scsi/sd.c |   28 ++++++++++++++++++++++++----
 1 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index fcba7d2..5ed75bf 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1104,11 +1104,31 @@ static int sd_sync_cache(struct scsi_disk *sdkp)
 		sd_print_result(sdkp, res);
 		if (driver_byte(res) & DRIVER_SENSE)
 			sd_print_sense_hdr(sdkp, &sshdr);
-	}
 
-	if (res)
-		return -EIO;
-	return 0;
+		/* we need to evaluate the error return  */
+		if ((scsi_sense_valid(&sshdr) &&
+			/* 0x3a is medium not present */
+			sshdr.asc == 0x3a))
+			/* this is no error here */
+			return 0;
+
+		switch (host_byte(res)) {
+		/* ignore errors due to racing a disconnection */
+		case DID_BAD_TARGET:
+		case DID_NO_CONNECT:	
+			return 0;
+		/* signal the upper layer it might try again */
+		case DID_BUS_BUSY:
+		case DID_IMM_RETRY:
+		case DID_REQUEUE:
+		case DID_SOFT_ERROR:
+			return -EBUSY;
+		default:
+			return -EIO;
+		}
+	} else {
+		return 0;
+	}
 }
 
 static void sd_rescan(struct device *dev)
-- 
1.7.1


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