Merge tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull 'struct fd' class updates from Al Viro:
 "The bulk of struct fd memory safety stuff

  Making sure that struct fd instances are destroyed in the same scope
  where they'd been created, getting rid of reassignments and passing
  them by reference, converting to CLASS(fd{,_pos,_raw}).

  We are getting very close to having the memory safety of that stuff
  trivial to verify"

* tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
  deal with the last remaing boolean uses of fd_file()
  css_set_fork(): switch to CLASS(fd_raw, ...)
  memcg_write_event_control(): switch to CLASS(fd)
  assorted variants of irqfd setup: convert to CLASS(fd)
  do_pollfd(): convert to CLASS(fd)
  convert do_select()
  convert vfs_dedupe_file_range().
  convert cifs_ioctl_copychunk()
  convert media_request_get_by_fd()
  convert spu_run(2)
  switch spufs_calls_{get,put}() to CLASS() use
  convert cachestat(2)
  convert do_preadv()/do_pwritev()
  fdget(), more trivial conversions
  fdget(), trivial conversions
  privcmd_ioeventfd_assign(): don't open-code eventfd_ctx_fdget()
  o2hb_region_dev_store(): avoid goto around fdget()/fdput()
  introduce "fd_pos" class, convert fdget_pos() users to it.
  fdget_raw() users: switch to CLASS(fd_raw)
  convert vmsplice() to CLASS(fd)
  ...

2 files changed, 7 insertions, 22 deletions

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 6b390b622b72..249ba5b72e9b 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -304,7 +304,6 @@ static int
 kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 {
 	struct kvm_kernel_irqfd *irqfd, *tmp;
-	struct fd f;
 	struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
 	int ret;
 	__poll_t events;
@@ -327,8 +326,8 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 	INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
 	seqcount_spinlock_init(&irqfd->irq_entry_sc, &kvm->irqfds.lock);
 
-	f = fdget(args->fd);
-	if (!fd_file(f)) {
+	CLASS(fd, f)(args->fd);
+	if (fd_empty(f)) {
 		ret = -EBADF;
 		goto out;
 	}
@@ -336,7 +335,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 	eventfd = eventfd_ctx_fileget(fd_file(f));
 	if (IS_ERR(eventfd)) {
 		ret = PTR_ERR(eventfd);
-		goto fail;
+		goto out;
 	}
 
 	irqfd->eventfd = eventfd;
@@ -440,12 +439,6 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 #endif
 
 	srcu_read_unlock(&kvm->irq_srcu, idx);
-
-	/*
-	 * do not drop the file until the irqfd is fully initialized, otherwise
-	 * we might race against the EPOLLHUP
-	 */
-	fdput(f);
 	return 0;
 
 fail:
@@ -458,8 +451,6 @@ fail:
 	if (eventfd && !IS_ERR(eventfd))
 		eventfd_ctx_put(eventfd);
 
-	fdput(f);
-
 out:
 	kfree(irqfd);
 	return ret;
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 388ae471d258..72aa1fdeb699 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -190,11 +190,10 @@ static int kvm_vfio_file_del(struct kvm_device *dev, unsigned int fd)
 {
 	struct kvm_vfio *kv = dev->private;
 	struct kvm_vfio_file *kvf;
-	struct fd f;
+	CLASS(fd, f)(fd);
 	int ret;
 
-	f = fdget(fd);
-	if (!fd_file(f))
+	if (fd_empty(f))
 		return -EBADF;
 
 	ret = -ENOENT;
@@ -220,9 +219,6 @@ static int kvm_vfio_file_del(struct kvm_device *dev, unsigned int fd)
 	kvm_vfio_update_coherency(dev);
 
 	mutex_unlock(&kv->lock);
-
-	fdput(f);
-
 	return ret;
 }
 
@@ -233,14 +229,13 @@ static int kvm_vfio_file_set_spapr_tce(struct kvm_device *dev,
 	struct kvm_vfio_spapr_tce param;
 	struct kvm_vfio *kv = dev->private;
 	struct kvm_vfio_file *kvf;
-	struct fd f;
 	int ret;
 
 	if (copy_from_user(&param, arg, sizeof(struct kvm_vfio_spapr_tce)))
 		return -EFAULT;
 
-	f = fdget(param.groupfd);
-	if (!fd_file(f))
+	CLASS(fd, f)(param.groupfd);
+	if (fd_empty(f))
 		return -EBADF;
 
 	ret = -ENOENT;
@@ -266,7 +261,6 @@ static int kvm_vfio_file_set_spapr_tce(struct kvm_device *dev,
 
 err_fdput:
 	mutex_unlock(&kv->lock);
-	fdput(f);
 	return ret;
 }
 #endif