[SCSI] make use of the residue value
USB sometimes doesn't return an error but instead returns a residue
value indicating part (or all) of the command wasn't completed. So if
the driver _done() error processing indicates the command was fully
processed, subtract off the residue so that this USB error gets
propagated.
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 110e776..36c92f9 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -855,9 +855,18 @@
good_bytes = scsi_bufflen(cmd);
if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
+ int old_good_bytes = good_bytes;
drv = scsi_cmd_to_driver(cmd);
if (drv->done)
good_bytes = drv->done(cmd);
+ /*
+ * USB may not give sense identifying bad sector and
+ * simply return a residue instead, so subtract off the
+ * residue if drv->done() error processing indicates no
+ * change to the completion length.
+ */
+ if (good_bytes == old_good_bytes)
+ good_bytes -= scsi_get_resid(cmd);
}
scsi_io_completion(cmd, good_bytes);
}