Re: [PATH] Port software to UML.

[hugang <gang_hu@soul.com.cn>]

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On Sun, 05 May 2002 19:22:39 -0500
Jeff Dike <jdike@karaya.com> wrote:

> gang_hu@soul.com.cn said:
> > Ther problem in bread.
> 
> No, the problem is in not understanding UML.
> 
> UML's state is somewhat more complicated than the state of a native kernel.
> 
> You also need to recreate 
> 	the host processes
> 	the ptrace relationships between the tracing thread and the other 
> processes
> 	open file descriptors
> 	and maybe a few other things that aren't coming to mind
> 
> 				Jeff

Now , I found the Problem. Fix that have two way 
--1 after the register disk , We not close it.
--2 at prepare_request , We check the dev->count, it not open , must open it first.

The 1.diff is use the 1 way.
the 2.diff is use the 2 way.

Which is the best?
  
-- 
thanks with regards!
hugang.

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--- ubd.c~	Mon May  6 10:42:56 2002
+++ ubd.c.2	Mon May  6 10:46:06 2002
@@ -720,7 +720,22 @@
 		end_request(0);
 		return(1);
 	}
-
+	if(!dev->count) {
+		if (dev->file) {
+			if(ubd_open_dev(dev) < 0){
+				printk(KERN_ERR "unable to open %s for validation\n",
+				       dev->file);
+				return 1;
+			}
+		} else  return 1;
+		
+		/* have to recompute sizes since we opened it */
+		err = ubd_file_size(dev, &dev->size);
+		if(err) {
+			ubd_close(dev);
+			return 1;
+		}
+	}
         req->sector += ubd_part[minor].start_sect;
         block = req->sector;
         nsect = req->current_nr_sectors;

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--- ubd.c~	Mon May  6 10:42:56 2002
+++ ubd.c	Mon May  6 10:49:11 2002
@@ -888,33 +888,26 @@
 	/* If it already has been opened we can check the partitions 
 	 * directly 
 	 */
-	if(dev->count){
-		part->start_sect = 0;
-		register_disk(&ubd_gendisk, MKDEV(MAJOR_NR, offset), pcount, 
-			      &ubd_blops, part->nr_sects);
-	} 
-	else if(dev->file){
-		if(ubd_open_dev(dev) < 0){
-			printk(KERN_ERR "unable to open %s for validation\n",
-			       dev->file);
-			return 1;
-		}
-
+	part->start_sect = 0;
+	if(!dev->count) {
+		if (dev->file) {
+			if(ubd_open_dev(dev) < 0){
+				printk(KERN_ERR "unable to open %s for validation\n",
+				       dev->file);
+				return 1;
+			}
+		} else  return 1;
+		
 		/* have to recompute sizes since we opened it */
 		err = ubd_file_size(dev, &dev->size);
 		if(err) {
 			ubd_close(dev);
 			return 1;
 		}
-		part->start_sect = 0;
 		part->nr_sects = dev->size / hardsect_sizes[offset];
-		register_disk(&ubd_gendisk, MKDEV(MAJOR_NR, offset), pcount, 
-			      &ubd_blops, part->nr_sects);
-
-		/* we are done so close it */
-		ubd_close(dev);
-	} 
-	else return(1);
+	}
+	register_disk(&ubd_gendisk, MKDEV(MAJOR_NR, offset), pcount, 
+		      &ubd_blops, part->nr_sects);
 	return(0);
 }