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

Pull virtio bugfixes from Michael Tsirkin:
 "Some small, obvious (in hindsight) bugfixes:

   - new ioctl in vhost-vdpa has a wrong # - not too late to fix

   - vhost has apparently been lacking an smp_rmb() - due to code
     duplication :( The duplication will be fixed in the next merge
     cycle, this is a minimal fix

   - an error message in vhost talks about guest moving used index -
     which of course never happens, guest only ever moves the available
     index

   - i2c-virtio didn't set the driver owner so it did not get refcounted
     correctly"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: correct misleading printing information
  vhost-vdpa: change ioctl # for VDPA_GET_VRING_SIZE
  virtio: store owner from modules with register_virtio_driver()
  vhost: Add smp_rmb() in vhost_enable_notify()
  vhost: Add smp_rmb() in vhost_vq_avail_empty()

diff --git a/Documentation/driver-api/virtio/writing_virtio_drivers.rst b/Documentation/driver-api/virtio/writing_virtio_drivers.rst
index e14c58796d250116107041b1be3e40aafa564656..e5de6f5d061a7c2162bc6fac628e542389602be3 100644 (file)
--- a/Documentation/driver-api/virtio/writing_virtio_drivers.rst
+++ b/Documentation/driver-api/virtio/writing_virtio_drivers.rst
@@ -97,7 +97,6 @@ like this::
 
        static struct virtio_driver virtio_dummy_driver = {
                .driver.name =  KBUILD_MODNAME,
-               .driver.owner = THIS_MODULE,
                .id_table =     id_table,
                .probe =        virtio_dummy_probe,
                .remove =       virtio_dummy_remove,

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 045f666b4f12a2a6416c93dafc2189af03662668..8995730ce0bfc82d193bd7128e51817fba43de76 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2515,7 +2515,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
                vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
 
                if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
-                       vq_err(vq, "Guest moved used index from %u to %u",
+                       vq_err(vq, "Guest moved avail index from %u to %u",
                                last_avail_idx, vq->avail_idx);
                        return -EFAULT;
                }
@@ -2799,9 +2799,19 @@ bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
        r = vhost_get_avail_idx(vq, &avail_idx);
        if (unlikely(r))
                return false;
+
        vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
+       if (vq->avail_idx != vq->last_avail_idx) {
+               /* Since we have updated avail_idx, the following
+                * call to vhost_get_vq_desc() will read available
+                * ring entries. Make sure that read happens after
+                * the avail_idx read.
+                */
+               smp_rmb();
+               return false;
+       }
 
-       return vq->avail_idx == vq->last_avail_idx;
+       return true;
 }
 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
 
@@ -2838,9 +2848,19 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
                       &vq->avail->idx, r);
                return false;
        }
+
        vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
+       if (vq->avail_idx != vq->last_avail_idx) {
+               /* Since we have updated avail_idx, the following
+                * call to vhost_get_vq_desc() will read available
+                * ring entries. Make sure that read happens after
+                * the avail_idx read.
+                */
+               smp_rmb();
+               return true;
+       }
 
-       return vq->avail_idx != vq->last_avail_idx;
+       return false;
 }
 EXPORT_SYMBOL_GPL(vhost_enable_notify);
 

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index f173587893cb34cadbfb4c6e548c158522c7749d..9510c551dce864d1e7df97f47a0c24fbcb8b8478 100644 (file)
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -362,14 +362,16 @@ static const struct bus_type virtio_bus = {
        .remove = virtio_dev_remove,
 };
 
-int register_virtio_driver(struct virtio_driver *driver)
+int __register_virtio_driver(struct virtio_driver *driver, struct module *owner)
 {
        /* Catch this early. */
        BUG_ON(driver->feature_table_size && !driver->feature_table);
        driver->driver.bus = &virtio_bus;
+       driver->driver.owner = owner;
+
        return driver_register(&driver->driver);
 }
-EXPORT_SYMBOL_GPL(register_virtio_driver);
+EXPORT_SYMBOL_GPL(__register_virtio_driver);
 
 void unregister_virtio_driver(struct virtio_driver *driver)
 {

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index b0201747a263a9526c5d60c2c2644a8e064a8439..26c4325aa3734eaa32ffbbdd862b151b93e7fdf8 100644 (file)
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -170,7 +170,7 @@ size_t virtio_max_dma_size(const struct virtio_device *vdev);
 
 /**
  * struct virtio_driver - operations for a virtio I/O driver
- * @driver: underlying device driver (populate name and owner).
+ * @driver: underlying device driver (populate name).
  * @id_table: the ids serviced by this driver.
  * @feature_table: an array of feature numbers supported by this driver.
  * @feature_table_size: number of entries in the feature table array.
@@ -208,7 +208,10 @@ static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
        return container_of(drv, struct virtio_driver, driver);
 }
 
-int register_virtio_driver(struct virtio_driver *drv);
+/* use a macro to avoid include chaining to get THIS_MODULE */
+#define register_virtio_driver(drv) \
+       __register_virtio_driver(drv, THIS_MODULE)
+int __register_virtio_driver(struct virtio_driver *drv, struct module *owner);
 void unregister_virtio_driver(struct virtio_driver *drv);
 
 /* module_virtio_driver() - Helper macro for drivers that don't do

diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index bea6973906134656d84299958258205932c23e04..b95dd84eef2db2311f985921064e65d96e3e2f4c 100644 (file)
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -179,12 +179,6 @@
 /* Get the config size */
 #define VHOST_VDPA_GET_CONFIG_SIZE     _IOR(VHOST_VIRTIO, 0x79, __u32)
 
-/* Get the count of all virtqueues */
-#define VHOST_VDPA_GET_VQS_COUNT       _IOR(VHOST_VIRTIO, 0x80, __u32)
-
-/* Get the number of virtqueue groups. */
-#define VHOST_VDPA_GET_GROUP_NUM       _IOR(VHOST_VIRTIO, 0x81, __u32)
-
 /* Get the number of address spaces. */
 #define VHOST_VDPA_GET_AS_NUM          _IOR(VHOST_VIRTIO, 0x7A, unsigned int)
 
@@ -228,10 +222,17 @@
 #define VHOST_VDPA_GET_VRING_DESC_GROUP        _IOWR(VHOST_VIRTIO, 0x7F,       \
                                              struct vhost_vring_state)
 
+
+/* Get the count of all virtqueues */
+#define VHOST_VDPA_GET_VQS_COUNT       _IOR(VHOST_VIRTIO, 0x80, __u32)
+
+/* Get the number of virtqueue groups. */
+#define VHOST_VDPA_GET_GROUP_NUM       _IOR(VHOST_VIRTIO, 0x81, __u32)
+
 /* Get the queue size of a specific virtqueue.
  * userspace set the vring index in vhost_vring_state.index
  * kernel set the queue size in vhost_vring_state.num
  */
-#define VHOST_VDPA_GET_VRING_SIZE      _IOWR(VHOST_VIRTIO, 0x80,       \
+#define VHOST_VDPA_GET_VRING_SIZE      _IOWR(VHOST_VIRTIO, 0x82,       \
                                              struct vhost_vring_state)
 #endif