On 19.10.2017 22:11, Christian Brauner wrote:
> - Add a struct containing two pointer to extents and wrap both the static
> extent
> array and the struct into a union. This is done in preparation for bumping
> the
> {g,u}idmap limits for user namespaces.
> - Add brackets around anonymous union when using designated initializers to
> initialize members in order to please gcc <= 4.4.
>
> Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
> ---
> Changelog 2017-10-19:
> * kernel/user.c: Use brackets around anonymous union when using designated
> initializers to initialize members. This is done to please gcc <= 4.4.
> ---
> include/linux/user_namespace.h | 18 +++++++++++++-----
> kernel/user.c | 30 ++++++++++++++++++------------
> 2 files changed, 31 insertions(+), 17 deletions(-)
>
> diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
> index c18e01252346..7c83d7f6289b 100644
> --- a/include/linux/user_namespace.h
> +++ b/include/linux/user_namespace.h
> @@ -12,13 +12,21 @@
>
> #define UID_GID_MAP_MAX_EXTENTS 5
>
> +struct uid_gid_extent {
> + u32 first;
> + u32 lower_first;
> + u32 count;
> +};
> +
> struct uid_gid_map { /* 64 bytes -- 1 cache line */
> u32 nr_extents;
> - struct uid_gid_extent {
> - u32 first;
> - u32 lower_first;
> - u32 count;
> - } extent[UID_GID_MAP_MAX_EXTENTS];
> + union {
> + struct uid_gid_extent extent[UID_GID_MAP_MAX_EXTENTS];
> + struct {
> + struct uid_gid_extent *forward;
> + struct uid_gid_extent *reverse;
> + };
> + };
> };
>
> #define USERNS_SETGROUPS_ALLOWED 1UL
> diff --git a/kernel/user.c b/kernel/user.c
> index 00281add65b2..9a20acce460d 100644
> --- a/kernel/user.c
> +++ b/kernel/user.c
> @@ -26,26 +26,32 @@
> struct user_namespace init_user_ns = {
> .uid_map = {
> .nr_extents = 1,
> - .extent[0] = {
> - .first = 0,
> - .lower_first = 0,
> - .count = 4294967295U,
> + {
> + .extent[0] = {
> + .first = 0,
> + .lower_first = 0,
> + .count = 4294967295U,
nit: ULONG_MAX ?
> + },
> },
> },
> .gid_map = {
> .nr_extents = 1,
> - .extent[0] = {
> - .first = 0,
> - .lower_first = 0,
> - .count = 4294967295U,
> + {
> + .extent[0] = {
> + .first = 0,
> + .lower_first = 0,
> + .count = 4294967295U,
> + },
> },
> },
> .projid_map = {
> .nr_extents = 1,
> - .extent[0] = {
> - .first = 0,
> - .lower_first = 0,
> - .count = 4294967295U,
> + {
> + .extent[0] = {
> + .first = 0,
> + .lower_first = 0,
> + .count = 4294967295U,
> + },
> },
> },
> .count = ATOMIC_INIT(3),
>
