[PATCH] libata: implement and apply ata_eh_qc_complete/retry()

Implement ata_eh_qc_complete/retry() using scsi_eh_finish_cmd() and
scsi_eh_flush_done_q().  This removes all eh scsicmd finish hacks from
low level drivers.

This change was first suggested by Jeff Garzik.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/scsi/sata_sil24.c b/drivers/scsi/sata_sil24.c
index 5a7a7b1..7222fc7 100644
--- a/drivers/scsi/sata_sil24.c
+++ b/drivers/scsi/sata_sil24.c
@@ -644,17 +644,9 @@
 		return;
 	}
 
-	/*
-	 * hack alert!  We cannot use the supplied completion
-	 * function from inside the ->eh_strategy_handler() thread.
-	 * libata is the only user of ->eh_strategy_handler() in
-	 * any kernel, so the default scsi_done() assumes it is
-	 * not being called from the SCSI EH.
-	 */
 	printk(KERN_ERR "ata%u: command timeout\n", ap->id);
-	qc->scsidone = scsi_finish_command;
 	qc->err_mask |= AC_ERR_TIMEOUT;
-	ata_qc_complete(qc);
+	ata_eh_qc_complete(qc);
 
 	sil24_reset_controller(ap);
 }