diff -urNp linux-1580/drivers/char/raw.c linux-1620/drivers/char/raw.c
--- linux-1580/drivers/char/raw.c	
+++ linux-1620/drivers/char/raw.c	
@@ -86,12 +86,6 @@ int raw_open(struct inode *inode, struct
 		filp->f_op = &raw_ctl_fops;
 		return 0;
 	}
-	
-	if (!filp->f_iobuf) {
-		err = alloc_kiovec(1, &filp->f_iobuf);
-		if (err)
-			return err;
-	}
 
 	down(&raw_devices[minor].mutex);
 	/*
@@ -295,7 +289,6 @@ ssize_t	rw_raw_dev(int rw, struct file *
 		   size_t size, loff_t *offp)
 {
 	struct kiobuf * iobuf;
-	int		new_iobuf;
 	int		err = 0;
 	unsigned long	blocknr, blocks;
 	size_t		transferred;
@@ -314,18 +307,10 @@ ssize_t	rw_raw_dev(int rw, struct file *
 
 	minor = MINOR(filp->f_dentry->d_inode->i_rdev);
 
-	new_iobuf = 0;
-	iobuf = filp->f_iobuf;
-	if (test_and_set_bit(0, &filp->f_iobuf_lock)) {
-		/*
-		 * A parallel read/write is using the preallocated iobuf
-		 * so just run slow and allocate a new one.
-		 */
-		err = alloc_kiovec(1, &iobuf);
-		if (err)
-			goto out;
-		new_iobuf = 1;
-	}
+	err = alloc_kiovec(1, &iobuf);
+	if (err)
+		return err;
+	
 
 	dev = to_kdev_t(raw_devices[minor].binding->bd_dev);
 	sector_size = raw_devices[minor].sector_size;
@@ -398,10 +383,6 @@ ssize_t	rw_raw_dev(int rw, struct file *
 	}
 
  out_free:
-	if (!new_iobuf)
-		clear_bit(0, &filp->f_iobuf_lock);
-	else
-		free_kiovec(1, &iobuf);
- out:	
+	free_kiovec(1, &iobuf);
 	return err;
 }
diff -urNp linux-1580/fs/iobuf.c linux-1620/fs/iobuf.c
--- linux-1580/fs/iobuf.c	
+++ linux-1620/fs/iobuf.c	
@@ -8,8 +8,6 @@
 
 #include <linux/iobuf.h>
 #include <linux/slab.h>
-#include <linux/vmalloc.h>
-
 
 static kmem_cache_t *kiobuf_cachep;
 
@@ -27,6 +25,8 @@ void end_kio_request(struct kiobuf *kiob
 
 static int kiobuf_init(struct kiobuf *iobuf)
 {
+	int retval;
+
 	init_waitqueue_head(&iobuf->wait_queue);
 	iobuf->array_len = 0;
 	iobuf->nr_pages = 0;
@@ -35,7 +35,16 @@ static int kiobuf_init(struct kiobuf *io
 	iobuf->blocks = NULL;
 	atomic_set(&iobuf->io_count, 0);
 	iobuf->end_io = NULL;
-	return expand_kiobuf(iobuf, KIO_STATIC_PAGES);
+	iobuf->initialized = 0;
+	retval = expand_kiobuf(iobuf, KIO_STATIC_PAGES);
+	if (retval) return retval;
+	retval = alloc_kiobuf_bhs(iobuf);
+	if (retval) {
+		kfree(iobuf->maplist);
+		return retval;
+	}
+	iobuf->initialized = 1;
+	return 0;
 }
 
 int alloc_kiobuf_bhs(struct kiobuf * kiobuf)
@@ -89,6 +98,21 @@ void free_kiobuf_bhs(struct kiobuf * kio
 	}
 }
 
+void kiobuf_ctor(void * objp, kmem_cache_t * cachep, unsigned long flag)
+{
+	struct kiobuf * iobuf = (struct kiobuf *) objp;
+	kiobuf_init(iobuf);
+}
+
+void kiobuf_dtor(void * objp, kmem_cache_t * cachep, unsigned long flag)
+{
+	struct kiobuf * iobuf = (struct kiobuf *) objp;
+	if (iobuf->initialized) {
+		kfree(iobuf->maplist);
+		free_kiobuf_bhs(iobuf);
+	}
+}
+
 int alloc_kiovec(int nr, struct kiobuf **bufp)
 {
 	int i;
@@ -98,10 +122,11 @@ int alloc_kiovec(int nr, struct kiobuf *
 		iobuf = kmem_cache_alloc(kiobuf_cachep, GFP_KERNEL);
 		if (unlikely(!iobuf))
 			goto nomem;
-		if (unlikely(kiobuf_init(iobuf)))
-			goto nomem2;
- 		if (unlikely(alloc_kiobuf_bhs(iobuf)))
-			goto nomem2;
+		if (unlikely(!iobuf->initialized)) {
+			/* try again to complete previously failed ctor */
+			if (unlikely(kiobuf_init(iobuf)))
+				goto nomem2;
+		}
 		bufp[i] = iobuf;
 	}
 	
@@ -121,11 +146,10 @@ void free_kiovec(int nr, struct kiobuf *
 	
 	for (i = 0; i < nr; i++) {
 		iobuf = bufp[i];
-		if (iobuf->locked)
-			unlock_kiovec(1, &iobuf);
-		kfree(iobuf->maplist);
-		free_kiobuf_bhs(iobuf);
-		kmem_cache_free(kiobuf_cachep, bufp[i]);
+		init_waitqueue_head(&iobuf->wait_queue);
+		iobuf->io_count.counter = 0;
+		iobuf->end_io = NULL;
+		kmem_cache_free(kiobuf_cachep, iobuf);
 	}
 }
 
@@ -180,7 +204,7 @@ repeat:
 void __init iobuf_cache_init(void)
 {
 	kiobuf_cachep = kmem_cache_create("kiobuf", sizeof(struct kiobuf),
-					  0, SLAB_HWCACHE_ALIGN, NULL, NULL);
+					  0, SLAB_HWCACHE_ALIGN, kiobuf_ctor, kiobuf_dtor);
 	if (!kiobuf_cachep)
 		panic("Cannot create kiobuf SLAB cache");
 }
diff -urNp linux-1580/include/linux/iobuf.h linux-1620/include/linux/iobuf.h
--- linux-1580/include/linux/iobuf.h	
+++ linux-1620/include/linux/iobuf.h	
@@ -39,7 +39,8 @@ struct kiobuf 
 	int		offset;		/* Offset to start of valid data */
 	int		length;		/* Number of valid bytes of data */
 
-	unsigned int	locked : 1;	/* If set, pages has been locked */
+	unsigned int	locked : 1,	/* If set, pages has been locked */
+			initialized:1;  /* If set, done initialize */
 
 	struct page **  maplist;
 	struct buffer_head ** bh;