Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/gi…

…t/mst/vhost

Pull virtio tests and fixes from Michael Tsirkin:
 "This fixes existing tests broken by barrier rework, and adds some new
  tests.

  Plus, there's a fix for an old bug in virtio-pci"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  tools/virtio: add ringtest utilities
  sh: fix smp_store_mb for !SMP
  tools/virtio: use virt_xxx barriers
  virtio_pci: fix use after free on release

arch/sh/include/asm/barrier.h

@@ -33,7 +33,6 @@
 #endif
 
 #define __smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0)
-#define smp_store_mb(var, value) __smp_store_mb(var, value)
 
 #include <asm-generic/barrier.h>
 

drivers/virtio/virtio_pci_common.c

@@ -545,6 +545,7 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
 static void virtio_pci_remove(struct pci_dev *pci_dev)
 {
 	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	struct device *dev = get_device(&vp_dev->vdev.dev);
 
 	unregister_virtio_device(&vp_dev->vdev);
 
@@ -554,6 +555,7 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
 		virtio_pci_modern_remove(vp_dev);
 
 	pci_disable_device(pci_dev);
+	put_device(dev);
 }
 
 static struct pci_driver virtio_pci_driver = {

tools/virtio/asm/barrier.h

@@ -1,15 +1,19 @@
 #if defined(__i386__) || defined(__x86_64__)
 #define barrier() asm volatile("" ::: "memory")
-#define mb() __sync_synchronize()
-
-#define smp_mb()	mb()
-# define dma_rmb()	barrier()
-# define dma_wmb()	barrier()
-# define smp_rmb()	barrier()
-# define smp_wmb()	barrier()
+#define virt_mb() __sync_synchronize()
+#define virt_rmb() barrier()
+#define virt_wmb() barrier()
+/* Atomic store should be enough, but gcc generates worse code in that case. */
+#define virt_store_mb(var, value)  do { \
+	typeof(var) virt_store_mb_value = (value); \
+	__atomic_exchange(&(var), &virt_store_mb_value, &virt_store_mb_value, \
+			  __ATOMIC_SEQ_CST); \
+	barrier(); \
+} while (0);
 /* Weak barriers should be used. If not - it's a bug */
-# define rmb()	abort()
-# define wmb()	abort()
+# define mb() abort()
+# define rmb() abort()
+# define wmb() abort()
 #else
 #error Please fill in barrier macros
 #endif

tools/virtio/linux/compiler.h

@@ -0,0 +1,9 @@
+#ifndef LINUX_COMPILER_H
+#define LINUX_COMPILER_H
+
+#define WRITE_ONCE(var, val) \
+	(*((volatile typeof(val) *)(&(var))) = (val))
+
+#define READ_ONCE(var) (*((volatile typeof(val) *)(&(var))))
+
+#endif

tools/virtio/linux/kernel.h

@@ -8,6 +8,7 @@
 #include <assert.h>
 #include <stdarg.h>
 
+#include <linux/compiler.h>
 #include <linux/types.h>
 #include <linux/printk.h>
 #include <linux/bug.h>

tools/virtio/ringtest/Makefile

@@ -0,0 +1,22 @@
+all:
+
+all: ring virtio_ring_0_9 virtio_ring_poll
+
+CFLAGS += -Wall
+CFLAGS += -pthread -O2 -ggdb
+LDFLAGS += -pthread -O2 -ggdb
+
+main.o: main.c main.h
+ring.o: ring.c main.h
+virtio_ring_0_9.o: virtio_ring_0_9.c main.h
+virtio_ring_poll.o: virtio_ring_poll.c virtio_ring_0_9.c main.h
+ring: ring.o main.o
+virtio_ring_0_9: virtio_ring_0_9.o main.o
+virtio_ring_poll: virtio_ring_poll.o main.o
+clean:
+	-rm main.o
+	-rm ring.o ring
+	-rm virtio_ring_0_9.o virtio_ring_0_9
+	-rm virtio_ring_poll.o virtio_ring_poll
+
+.PHONY: all clean

tools/virtio/ringtest/README

@@ -0,0 +1,2 @@
+Partial implementation of various ring layouts, useful to tune virtio design.
+Uses shared memory heavily.