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)
  ...

1 files changed, 5 insertions, 23 deletions

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 4f75bc876454..13a10f3294a8 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -965,10 +965,11 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd)
 	struct privcmd_kernel_irqfd *kirqfd, *tmp;
 	unsigned long flags;
 	__poll_t events;
-	struct fd f;
 	void *dm_op;
 	int ret, idx;
 
+	CLASS(fd, f)(irqfd->fd);
+
 	kirqfd = kzalloc(sizeof(*kirqfd) + irqfd->size, GFP_KERNEL);
 	if (!kirqfd)
 		return -ENOMEM;
@@ -984,8 +985,7 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd)
 	kirqfd->dom = irqfd->dom;
 	INIT_WORK(&kirqfd->shutdown, irqfd_shutdown);
 
-	f = fdget(irqfd->fd);
-	if (!fd_file(f)) {
+	if (fd_empty(f)) {
 		ret = -EBADF;
 		goto error_kfree;
 	}
@@ -993,7 +993,7 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd)
 	kirqfd->eventfd = eventfd_ctx_fileget(fd_file(f));
 	if (IS_ERR(kirqfd->eventfd)) {
 		ret = PTR_ERR(kirqfd->eventfd);
-		goto error_fd_put;
+		goto error_kfree;
 	}
 
 	/*
@@ -1026,20 +1026,11 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd)
 		irqfd_inject(kirqfd);
 
 	srcu_read_unlock(&irqfds_srcu, idx);
-
-	/*
-	 * Do not drop the file until the kirqfd is fully initialized, otherwise
-	 * we might race against the EPOLLHUP.
-	 */
-	fdput(f);
 	return 0;
 
 error_eventfd:
 	eventfd_ctx_put(kirqfd->eventfd);
 
-error_fd_put:
-	fdput(f);
-
 error_kfree:
 	kfree(kirqfd);
 	return ret;
@@ -1350,7 +1341,6 @@ static int privcmd_ioeventfd_assign(struct privcmd_ioeventfd *ioeventfd)
 	struct privcmd_kernel_ioeventfd *kioeventfd;
 	struct privcmd_kernel_ioreq *kioreq;
 	unsigned long flags;
-	struct fd f;
 	int ret;
 
 	/* Check for range overflow */
@@ -1370,15 +1360,7 @@ static int privcmd_ioeventfd_assign(struct privcmd_ioeventfd *ioeventfd)
 	if (!kioeventfd)
 		return -ENOMEM;
 
-	f = fdget(ioeventfd->event_fd);
-	if (!fd_file(f)) {
-		ret = -EBADF;
-		goto error_kfree;
-	}
-
-	kioeventfd->eventfd = eventfd_ctx_fileget(fd_file(f));
-	fdput(f);
-
+	kioeventfd->eventfd = eventfd_ctx_fdget(ioeventfd->event_fd);
 	if (IS_ERR(kioeventfd->eventfd)) {
 		ret = PTR_ERR(kioeventfd->eventfd);
 		goto error_kfree;