vhost: don't hold onto file pointer for VHOST_SET_LOG_FD

We already hold a reference to the eventfd_ctx, which is sufficient;
there's no need to hold a reference to the struct file as well.  So get
rid of vhost_dev->log_file.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>

2 files changed, 5 insertions, 20 deletions

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 40a72d15361f..66775446248a 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -419,7 +419,6 @@ void vhost_dev_init(struct vhost_dev *dev,
         dev->nvqs = nvqs;
         mutex_init(&dev->mutex);
         dev->log_ctx = NULL;
-        dev->log_file = NULL;
         dev->umem = NULL;
         dev->iotlb = NULL;
         dev->mm = NULL;
@@ -625,9 +624,6 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
         if (dev->log_ctx)
                 eventfd_ctx_put(dev->log_ctx);
         dev->log_ctx = NULL;
-        if (dev->log_file)
-                fput(dev->log_file);
-        dev->log_file = NULL;
         /* No one will access memory at this point */
         vhost_umem_clean(dev->umem);
         dev->umem = NULL;
@@ -1572,8 +1568,7 @@ EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
 /* Caller must have device mutex */
 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
 {
-        struct file *eventfp, *filep = NULL;
-        struct eventfd_ctx *ctx = NULL;
+        struct eventfd_ctx *ctx;
         u64 p;
         long r;
         int i, fd;
@@ -1619,19 +1614,12 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
                 r = get_user(fd, (int __user *)argp);
                 if (r < 0)
                         break;
-                eventfp = fd == -1 ? NULL : eventfd_fget(fd);
-                if (IS_ERR(eventfp)) {
-                        r = PTR_ERR(eventfp);
+                ctx = fd == -1 ? NULL : eventfd_ctx_fdget(fd);
+                if (IS_ERR(ctx)) {
+                        r = PTR_ERR(ctx);
                         break;
                 }
-                if (eventfp != d->log_file) {
-                        filep = d->log_file;
-                        d->log_file = eventfp;
-                        ctx = d->log_ctx;
-                        d->log_ctx = eventfp ?
-                                eventfd_ctx_fileget(eventfp) : NULL;
-                } else
-                        filep = eventfp;
+                swap(ctx, d->log_ctx);
                 for (i = 0; i < d->nvqs; ++i) {
                         mutex_lock(&d->vqs[i]->mutex);
                         d->vqs[i]->log_ctx = d->log_ctx;
@@ -1639,8 +1627,6 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
                 }
                 if (ctx)
                         eventfd_ctx_put(ctx);
-                if (filep)
-                        fput(filep);
                 break;
         default:
                 r = -ENOIOCTLCMD;
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index e3c463ce3d48..45d12b01cfe4 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -157,7 +157,6 @@ struct vhost_dev {
         struct mutex mutex;
         struct vhost_virtqueue **vqs;
         int nvqs;
-        struct file *log_file;
         struct eventfd_ctx *log_ctx;
         struct llist_head work_list;
         struct task_struct *worker;