--- drivers/cdrom/mcdx.c.orig	2007-04-02 00:25:09.000000000 +0200
+++ drivers/cdrom/mcdx.c	2007-04-02 00:37:53.000000000 +0200
@@ -577,11 +577,20 @@
 	if (!req)
 		return;
 
+	if (!blk_fs_request(req)) {
+		spin_lock_irq(q->queue_lock);
+		end_request(req, 0);
+		goto again;
+	}
+
+	spin_unlock_irq(q->queue_lock);
+
 	stuffp = req->rq_disk->private_data;
 
 	if (!stuffp->present) {
 		xwarn("do_request(): bad device: %s\n",req->rq_disk->disk_name);
 		xtrace(REQUEST, "end_request(0): bad device\n");
+		spin_lock_irq(q->queue_lock);
 		end_request(req, 0);
 		return;
 	}
@@ -589,6 +598,7 @@
 	if (stuffp->audio) {
 		xwarn("do_request() attempt to read from audio cd\n");
 		xtrace(REQUEST, "end_request(0): read from audio\n");
+		spin_lock_irq(q->queue_lock);
 		end_request(req, 0);
 		return;
 	}
@@ -596,9 +606,10 @@
 	xtrace(REQUEST, "do_request() (%lu + %lu)\n",
 	       req->sector, req->nr_sectors);
 
-	if (req->cmd != READ) {
+	if (rq_data_dir(req) != READ) {
 		xwarn("do_request(): non-read command to cd!!\n");
 		xtrace(REQUEST, "end_request(0): write\n");
+		spin_lock_irq(q->queue_lock);
 		end_request(req, 0);
 		return;
 	}
@@ -613,6 +624,7 @@
 					  req->nr_sectors);
 
 			if (i == -1) {
+				spin_lock_irq(q->queue_lock);
 				end_request(req, 0);
 				goto again;
 			}
@@ -620,10 +632,12 @@
 			req->nr_sectors -= i;
 			req->buffer += (i * 512);
 		}
+		spin_lock_irq(q->queue_lock);
 		end_request(req, 1);
 		goto again;
 
 		xtrace(REQUEST, "end_request(1)\n");
+		spin_lock_irq(q->queue_lock);
 		end_request(req, 1);
 	}