scsi: revert "[SCSI] Get rid of scsi_cmnd->done"

This reverts commit 6f5391c283d7fdcf24bf40786ea79061919d1e1d ("[SCSI]
Get rid of scsi_cmnd->done") that was supposed to be a cleanup commit,
but apparently it causes regressions:

  Bug 9370 - v2.6.24-rc2-409-g9418d5d: attempt to access beyond end of device
  http://bugzilla.kernel.org/show_bug.cgi?id=9370

this patch should be reintroduced in a more split-up form to make
testing of it easier.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Matthew Wilcox <matthew@wil.cx>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index c619990..a0c4e13 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -78,7 +78,6 @@
 
 static int sr_probe(struct device *);
 static int sr_remove(struct device *);
-static int sr_done(struct scsi_cmnd *);
 
 static struct scsi_driver sr_template = {
 	.owner			= THIS_MODULE,
@@ -87,7 +86,6 @@
 		.probe		= sr_probe,
 		.remove		= sr_remove,
 	},
-	.done			= sr_done,
 };
 
 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
@@ -210,12 +208,12 @@
 }
  
 /*
- * sr_done is the interrupt routine for the device driver.
+ * rw_intr is the interrupt routine for the device driver.
  *
- * It will be notified on the end of a SCSI read / write, and will take one
+ * It will be notified on the end of a SCSI read / write, and will take on
  * of several actions based on success or failure.
  */
-static int sr_done(struct scsi_cmnd *SCpnt)
+static void rw_intr(struct scsi_cmnd * SCpnt)
 {
 	int result = SCpnt->result;
 	int this_count = SCpnt->request_bufflen;
@@ -288,7 +286,12 @@
 		}
 	}
 
-	return good_bytes;
+	/*
+	 * This calls the generic completion function, now that we know
+	 * how many actual sectors finished, and how many sectors we need
+	 * to say have failed.
+	 */
+	scsi_io_completion(SCpnt, good_bytes);
 }
 
 static int sr_prep_fn(struct request_queue *q, struct request *rq)
@@ -425,6 +428,12 @@
 	SCpnt->timeout_per_command = timeout;
 
 	/*
+	 * This is the completion routine we use.  This is matched in terms
+	 * of capability to this function.
+	 */
+	SCpnt->done = rw_intr;
+
+	/*
 	 * This indicates that the command is ready from our end to be
 	 * queued.
 	 */