file: add fput() cleanup helper

Add a simple helper to put a file reference.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Josef Bacik <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

Author: brauner

include/linux/file.h

@@ -11,6 +11,7 @@
 #include <linux/posix_types.h>
 #include <linux/errno.h>
 #include <linux/cleanup.h>
+#include <linux/err.h>
 
 struct file;
 
@@ -96,6 +97,7 @@ extern void put_unused_fd(unsigned int fd);
 
 DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T),
 	     get_unused_fd_flags(flags), unsigned flags)
+DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T))
 
 /*
  * take_fd() will take care to set @fd to -EBADF ensuring that