Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio barrier rework+fixes from Michael Tsirkin:
 "This adds a new kind of barrier, and reworks virtio and xen to use it.

  Plus some fixes here and there"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (44 commits)
  checkpatch: add virt barriers
  checkpatch: check for __smp outside barrier.h
  checkpatch.pl: add missing memory barriers
  virtio: make find_vqs() checkpatch.pl-friendly
  virtio_balloon: fix race between migration and ballooning
  virtio_balloon: fix race by fill and leak
  s390: more efficient smp barriers
  s390: use generic memory barriers
  xen/events: use virt_xxx barriers
  xen/io: use virt_xxx barriers
  xenbus: use virt_xxx barriers
  virtio_ring: use virt_store_mb
  sh: move xchg_cmpxchg to a header by itself
  sh: support 1 and 2 byte xchg
  virtio_ring: update weak barriers to use virt_xxx
  Revert "virtio_ring: Update weak barriers to use dma_wmb/rmb"
  asm-generic: implement virt_xxx memory barriers
  x86: define __smp_xxx
  xtensa: define __smp_xxx
  tile: define __smp_xxx
  ...

15 files changed, 29 insertions, 25 deletions

diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 06496a128162..4150873d432e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -130,7 +130,7 @@ int virtio_gpu_driver_load(struct drm_device *dev, unsigned long flags)
 	static vq_callback_t *callbacks[] = {
 		virtio_gpu_ctrl_ack, virtio_gpu_cursor_ack
 	};
-	static const char *names[] = { "control", "cursor" };
+	static const char * const names[] = { "control", "cursor" };
 
 	struct virtio_gpu_device *vgdev;
 	/* this will expand later */
diff --git a/drivers/misc/mic/card/mic_virtio.c b/drivers/misc/mic/card/mic_virtio.c
index e486a0c26267..f6ed57d3125c 100644
--- a/drivers/misc/mic/card/mic_virtio.c
+++ b/drivers/misc/mic/card/mic_virtio.c
@@ -311,7 +311,7 @@ unmap:
 static int mic_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			struct virtqueue *vqs[],
 			vq_callback_t *callbacks[],
-			const char *names[])
+			const char * const names[])
 {
 	struct mic_vdev *mvdev = to_micvdev(vdev);
 	struct mic_device_ctrl __iomem *dc = mvdev->dc;
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index e1a10232a943..e44872fb9e5e 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -147,7 +147,7 @@ static void rproc_virtio_del_vqs(struct virtio_device *vdev)
 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 		       struct virtqueue *vqs[],
 		       vq_callback_t *callbacks[],
-		       const char *names[])
+		       const char * const names[])
 {
 	struct rproc *rproc = vdev_to_rproc(vdev);
 	int i, ret;
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 73354ee27877..1fcd27c1f183 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -945,7 +945,7 @@ static void rpmsg_ns_cb(struct rpmsg_channel *rpdev, void *data, int len,
 static int rpmsg_probe(struct virtio_device *vdev)
 {
 	vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
-	const char *names[] = { "input", "output" };
+	static const char * const names[] = { "input", "output" };
 	struct virtqueue *vqs[2];
 	struct virtproc_info *vrp;
 	void *bufs_va;
diff --git a/drivers/s390/virtio/kvm_virtio.c b/drivers/s390/virtio/kvm_virtio.c
index 53fb975c404b..1d060fd293a3 100644
--- a/drivers/s390/virtio/kvm_virtio.c
+++ b/drivers/s390/virtio/kvm_virtio.c
@@ -255,7 +255,7 @@ static void kvm_del_vqs(struct virtio_device *vdev)
 static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			struct virtqueue *vqs[],
 			vq_callback_t *callbacks[],
-			const char *names[])
+			const char * const names[])
 {
 	struct kvm_device *kdev = to_kvmdev(vdev);
 	int i;
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 1b831598df7c..bf2d1300a957 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -635,7 +635,7 @@ out:
 static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			       struct virtqueue *vqs[],
 			       vq_callback_t *callbacks[],
-			       const char *names[])
+			       const char * const names[])
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 	unsigned long *indicatorp = NULL;
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 7efc32945810..0c3691f46575 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -209,8 +209,8 @@ static unsigned leak_balloon(struct virtio_balloon *vb, size_t num)
 	 */
 	if (vb->num_pfns != 0)
 		tell_host(vb, vb->deflate_vq);
-	mutex_unlock(&vb->balloon_lock);
 	release_pages_balloon(vb);
+	mutex_unlock(&vb->balloon_lock);
 	return num_freed_pages;
 }
 
@@ -388,7 +388,7 @@ static int init_vqs(struct virtio_balloon *vb)
 {
 	struct virtqueue *vqs[3];
 	vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request };
-	const char *names[] = { "inflate", "deflate", "stats" };
+	static const char * const names[] = { "inflate", "deflate", "stats" };
 	int err, nvqs;
 
 	/*
diff --git a/drivers/virtio/virtio_input.c b/drivers/virtio/virtio_input.c
index c96944b59856..350a2a5a49db 100644
--- a/drivers/virtio/virtio_input.c
+++ b/drivers/virtio/virtio_input.c
@@ -170,7 +170,7 @@ static int virtinput_init_vqs(struct virtio_input *vi)
 	struct virtqueue *vqs[2];
 	vq_callback_t *cbs[] = { virtinput_recv_events,
 				 virtinput_recv_status };
-	static const char *names[] = { "events", "status" };
+	static const char * const names[] = { "events", "status" };
 	int err;
 
 	err = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names);
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index f499d9da7237..745c6ee1bb3e 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -482,7 +482,7 @@ error_available:
 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 		       struct virtqueue *vqs[],
 		       vq_callback_t *callbacks[],
-		       const char *names[])
+		       const char * const names[])
 {
 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 	unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 78f804af6c20..36205c27c4d0 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -296,7 +296,7 @@ void vp_del_vqs(struct virtio_device *vdev)
 static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			      struct virtqueue *vqs[],
 			      vq_callback_t *callbacks[],
-			      const char *names[],
+			      const char * const names[],
 			      bool use_msix,
 			      bool per_vq_vectors)
 {
@@ -376,7 +376,7 @@ error_find:
 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 		struct virtqueue *vqs[],
 		vq_callback_t *callbacks[],
-		const char *names[])
+		const char * const names[])
 {
 	int err;
 
diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
index b976d968e793..2cc252270b2d 100644
--- a/drivers/virtio/virtio_pci_common.h
+++ b/drivers/virtio/virtio_pci_common.h
@@ -139,7 +139,7 @@ void vp_del_vqs(struct virtio_device *vdev);
 int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 		       struct virtqueue *vqs[],
 		       vq_callback_t *callbacks[],
-		       const char *names[]);
+		       const char * const names[]);
 const char *vp_bus_name(struct virtio_device *vdev);
 
 /* Setup the affinity for a virtqueue:
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 8e5cf194cc0b..c0c11fad4611 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -418,7 +418,7 @@ err_new_queue:
 static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			      struct virtqueue *vqs[],
 			      vq_callback_t *callbacks[],
-			      const char *names[])
+			      const char * const names[])
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	struct virtqueue *vq;
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index ee663c458b20..e12e385f7ac3 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -517,10 +517,10 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
 	/* If we expect an interrupt for the next entry, tell host
 	 * by writing event index and flush out the write before
 	 * the read in the next get_buf call. */
-	if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
-		vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, vq->last_used_idx);
-		virtio_mb(vq->weak_barriers);
-	}
+	if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT))
+		virtio_store_mb(vq->weak_barriers,
+				&vring_used_event(&vq->vring),
+				cpu_to_virtio16(_vq->vdev, vq->last_used_idx));
 
 #ifdef DEBUG
 	vq->last_add_time_valid = false;
@@ -653,8 +653,11 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
 	}
 	/* TODO: tune this threshold */
 	bufs = (u16)(vq->avail_idx_shadow - vq->last_used_idx) * 3 / 4;
-	vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs);
-	virtio_mb(vq->weak_barriers);
+
+	virtio_store_mb(vq->weak_barriers,
+			&vring_used_event(&vq->vring),
+			cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs));
+
 	if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->vring.used->idx) - vq->last_used_idx) > bufs)) {
 		END_USE(vq);
 		return false;
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index 96a1b8da5371..eff2b88003d9 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -41,6 +41,7 @@
 #include <linux/percpu.h>
 #include <linux/cpu.h>
 
+#include <asm/barrier.h>
 #include <asm/sync_bitops.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
@@ -296,7 +297,7 @@ static void consume_one_event(unsigned cpu,
 	 * control block.
 	 */
 	if (head == 0) {
-		rmb(); /* Ensure word is up-to-date before reading head. */
+		virt_rmb(); /* Ensure word is up-to-date before reading head. */
 		head = control_block->head[priority];
 	}
 
diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c
index fdb0f339d0a7..ecdecce80a6c 100644
--- a/drivers/xen/xenbus/xenbus_comms.c
+++ b/drivers/xen/xenbus/xenbus_comms.c
@@ -123,14 +123,14 @@ int xb_write(const void *data, unsigned len)
 			avail = len;
 
 		/* Must write data /after/ reading the consumer index. */
-		mb();
+		virt_mb();
 
 		memcpy(dst, data, avail);
 		data += avail;
 		len -= avail;
 
 		/* Other side must not see new producer until data is there. */
-		wmb();
+		virt_wmb();
 		intf->req_prod += avail;
 
 		/* Implies mb(): other side will see the updated producer. */
@@ -180,14 +180,14 @@ int xb_read(void *data, unsigned len)
 			avail = len;
 
 		/* Must read data /after/ reading the producer index. */
-		rmb();
+		virt_rmb();
 
 		memcpy(data, src, avail);
 		data += avail;
 		len -= avail;
 
 		/* Other side must not see free space until we've copied out */
-		mb();
+		virt_mb();
 		intf->rsp_cons += avail;
 
 		pr_debug("Finished read of %i bytes (%i to go)\n", avail, len);