bpf: more trivial fdget() conversions

All failure exits prior to fdget() leave the scope, all matching fdput()
are immediately followed by leaving the scope.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index d75e4e68801e15f3b35c9b5fcbeb6ca073ccc134..65dcd92d0b2c5d80cb42029fbc883c9a1543d4e6 100644 (file)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4901,33 +4901,25 @@ static int bpf_link_get_info_by_fd(struct file *file,
 static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
                                  union bpf_attr __user *uattr)
 {
-       int ufd = attr->info.bpf_fd;
-       struct fd f;
-       int err;
-
        if (CHECK_ATTR(BPF_OBJ_GET_INFO_BY_FD))
                return -EINVAL;
 
-       f = fdget(ufd);
-       if (!fd_file(f))
+       CLASS(fd, f)(attr->info.bpf_fd);
+       if (fd_empty(f))
                return -EBADFD;
 
        if (fd_file(f)->f_op == &bpf_prog_fops)
-               err = bpf_prog_get_info_by_fd(fd_file(f), fd_file(f)->private_data, attr,
+               return bpf_prog_get_info_by_fd(fd_file(f), fd_file(f)->private_data, attr,
                                              uattr);
        else if (fd_file(f)->f_op == &bpf_map_fops)
-               err = bpf_map_get_info_by_fd(fd_file(f), fd_file(f)->private_data, attr,
+               return bpf_map_get_info_by_fd(fd_file(f), fd_file(f)->private_data, attr,
                                             uattr);
        else if (fd_file(f)->f_op == &btf_fops)
-               err = bpf_btf_get_info_by_fd(fd_file(f), fd_file(f)->private_data, attr, uattr);
+               return bpf_btf_get_info_by_fd(fd_file(f), fd_file(f)->private_data, attr, uattr);
        else if (fd_file(f)->f_op == &bpf_link_fops || fd_file(f)->f_op == &bpf_link_fops_poll)
-               err = bpf_link_get_info_by_fd(fd_file(f), fd_file(f)->private_data,
+               return bpf_link_get_info_by_fd(fd_file(f), fd_file(f)->private_data,
                                              attr, uattr);
-       else
-               err = -EINVAL;
-
-       fdput(f);
-       return err;
+       return -EINVAL;
 }
 
 #define BPF_BTF_LOAD_LAST_FIELD btf_token_fd