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, 12 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index e7fe07f7963d..196779e8e396 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -4423,31 +4423,25 @@ SYSCALL_DEFINE4(cachestat, unsigned int, fd,
 		struct cachestat_range __user *, cstat_range,
 		struct cachestat __user *, cstat, unsigned int, flags)
 {
-	struct fd f = fdget(fd);
+	CLASS(fd, f)(fd);
 	struct address_space *mapping;
 	struct cachestat_range csr;
 	struct cachestat cs;
 	pgoff_t first_index, last_index;
 
-	if (!fd_file(f))
+	if (fd_empty(f))
 		return -EBADF;
 
 	if (copy_from_user(&csr, cstat_range,
-			sizeof(struct cachestat_range))) {
-		fdput(f);
+			sizeof(struct cachestat_range)))
 		return -EFAULT;
-	}
 
 	/* hugetlbfs is not supported */
-	if (is_file_hugepages(fd_file(f))) {
-		fdput(f);
+	if (is_file_hugepages(fd_file(f)))
 		return -EOPNOTSUPP;
-	}
 
-	if (flags != 0) {
-		fdput(f);
+	if (flags != 0)
 		return -EINVAL;
-	}
 
 	first_index = csr.off >> PAGE_SHIFT;
 	last_index =
@@ -4455,7 +4449,6 @@ SYSCALL_DEFINE4(cachestat, unsigned int, fd,
 	memset(&cs, 0, sizeof(struct cachestat));
 	mapping = fd_file(f)->f_mapping;
 	filemap_cachestat(mapping, first_index, last_index, &cs);
-	fdput(f);
 
 	if (copy_to_user(cstat, &cs, sizeof(struct cachestat)))
 		return -EFAULT;