Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull virtio updates from Rusty Russell:
 "No real surprises"

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  MAINTAINERS: add tools/virtio/ under virtio
  tools/virtio: move module license stub to module.h
  virtio: include asm/barrier explicitly
  virtio: VIRTIO_F_ANY_LAYOUT feature
  lguest: fix example launcher compilation for broken glibc headers.
  virtio-net: fix the race between channels setting and refill
  tools/lguest: real barriers.
  tools/lguest: fix missing rmb().
  virtio_balloon: leak_balloon(): only tell host if we got pages deflated
  virtio-pci: fix leaks of msix_affinity_masks
  Fix comment typo "CONFIG_PAE"

tools/lguest/Makefile

@@ -1,5 +1,4 @@
 # This creates the demonstration utility "lguest" which runs a Linux guest.
-# Missing headers?  Add "-I../../../include -I../../../arch/x86/include"
 CFLAGS:=-m32 -Wall -Wmissing-declarations -Wmissing-prototypes -O3 -U_FORTIFY_SOURCE
 
 all: lguest

tools/lguest/lguest.c

@@ -42,14 +42,6 @@
 #include <pwd.h>
 #include <grp.h>
 
-#include <linux/virtio_config.h>
-#include <linux/virtio_net.h>
-#include <linux/virtio_blk.h>
-#include <linux/virtio_console.h>
-#include <linux/virtio_rng.h>
-#include <linux/virtio_ring.h>
-#include <asm/bootparam.h>
-#include "../../include/linux/lguest_launcher.h"
 /*L:110
  * We can ignore the 43 include files we need for this program, but I do want
  * to draw attention to the use of kernel-style types.
@@ -65,6 +57,15 @@ typedef uint16_t u16;
 typedef uint8_t u8;
 /*:*/
 
+#include <linux/virtio_config.h>
+#include <linux/virtio_net.h>
+#include <linux/virtio_blk.h>
+#include <linux/virtio_console.h>
+#include <linux/virtio_rng.h>
+#include <linux/virtio_ring.h>
+#include <asm/bootparam.h>
+#include "../../include/linux/lguest_launcher.h"
+
 #define BRIDGE_PFX "bridge:"
 #ifndef SIOCBRADDIF
 #define SIOCBRADDIF	0x89a2		/* add interface to bridge      */
@@ -177,7 +178,8 @@ static struct termios orig_term;
  * in precise order.
  */
 #define wmb() __asm__ __volatile__("" : : : "memory")
-#define mb() __asm__ __volatile__("" : : : "memory")
+#define rmb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory")
+#define mb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory")
 
 /* Wrapper for the last available index.  Makes it easier to change. */
 #define lg_last_avail(vq)	((vq)->last_avail_idx)
@@ -676,6 +678,12 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq,
 		errx(1, "Guest moved used index from %u to %u",
 		     last_avail, vq->vring.avail->idx);
 
+	/* 
+	 * Make sure we read the descriptor number *after* we read the ring
+	 * update; don't let the cpu or compiler change the order.
+	 */
+	rmb();
+
 	/*
 	 * Grab the next descriptor number they're advertising, and increment
 	 * the index we've seen.
@@ -694,6 +702,12 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq,
 	desc = vq->vring.desc;
 	i = head;
 
+	/*
+	 * We have to read the descriptor after we read the descriptor number,
+	 * but there's a data dependency there so the CPU shouldn't reorder
+	 * that: no rmb() required.
+	 */
+
 	/*
 	 * If this is an indirect entry, then this buffer contains a descriptor
 	 * table which we handle as if it's any normal descriptor chain.

tools/virtio/linux/module.h

@@ -1 +1,6 @@
 #include <linux/export.h>
+
+#define MODULE_LICENSE(__MODULE_LICENSE_value) \
+	static __attribute__((unused)) const char *__MODULE_LICENSE_name = \
+		__MODULE_LICENSE_value
+

tools/virtio/linux/virtio.h

@@ -45,9 +45,6 @@ struct virtqueue {
 	void *priv;
 };
 
-#define MODULE_LICENSE(__MODULE_LICENSE_value) \
-	const char *__MODULE_LICENSE_name = __MODULE_LICENSE_value
-
 /* Interfaces exported by virtio_ring. */
 int virtqueue_add_sgs(struct virtqueue *vq,
 		      struct scatterlist *sgs[],