From 33b3ab6631ded858f811d6f5f6d7af4ac15dbc65 Mon Sep 17 00:00:00 2001
From: Michal Marek <mmarek@suse.cz>
Date: Fri, 16 Sep 2011 11:56:20 +0200
Subject: [PATCH 3/3] kabi: Add placeholders to a couple of important
 structures
Patch-mainline: Never, kabi
References: fate#312013

Add a void* suse_kabi_padding placeholder to the following structures:
struct smp_ops
struct vm_area_struct
struct mm_struct
struct zone
  - adding an explicit padding here is not strictly required, but can
    serve as documentation that there is some space
struct pglist_data
struct vfsmount
struct module
struct signal_struct
struct sched_entity
struct sock
struct task_struct

The idea is that when a fix appears that requires a new member in any of
these structures, we use this padding:

  #ifdef __GENKSYMS__
          void *suse_kabi_padding;
  #else
          long foo;
  #endif

And we don't have to worry about changing size of the structure, as long
as the new member is a pointer or a long.

Signed-off-by: Michal Marek <mmarek@suse.cz>

---
 arch/x86/include/asm/mmu.h   |    1 +
 arch/x86/include/asm/smp.h   |    1 +
 include/linux/device.h       |    7 +++++++
 include/linux/mm_types.h     |    1 +
 include/linux/mmzone.h       |    1 +
 include/linux/module.h       |    1 +
 include/linux/mount.h        |    1 +
 include/linux/sched.h        |    2 ++
 include/linux/sched/signal.h |    1 +
 include/net/sock.h           |    1 +
 10 files changed, 17 insertions(+)

--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -54,6 +54,7 @@ typedef struct {
 	/* address of the bounds directory */
 	void __user *bd_addr;
 #endif
+	void *suse_kabi_padding;
 } mm_context_t;
 
 #define INIT_MM_CONTEXT(mm)						\
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -59,6 +59,7 @@ struct smp_ops {
 
 	void (*send_call_func_ipi)(const struct cpumask *mask);
 	void (*send_call_func_single_ipi)(int cpu);
+	void *suse_kabi_padding;
 };
 
 /* Globals due to paravirt */
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -144,6 +144,8 @@ struct bus_type {
 	struct lock_class_key lock_key;
 
 	bool need_parent_lock;
+
+	void *suse_kabi_padding;
 };
 
 extern int __must_check bus_register(struct bus_type *bus);
@@ -301,6 +303,8 @@ struct device_driver {
 	void (*coredump) (struct device *dev);
 
 	struct driver_private *p;
+
+	void *suse_kabi_padding;
 };
 
 
@@ -428,6 +432,8 @@ struct class {
 	const struct dev_pm_ops *pm;
 
 	struct subsys_private *p;
+
+	void *suse_kabi_padding;
 };
 
 struct class_dev_iter {
@@ -1074,6 +1080,7 @@ struct device {
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
 	bool			dma_coherent:1;
 #endif
+	void			*suse_kabi_padding;
 };
 
 static inline struct device *kobj_to_dev(struct kobject *kobj)
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -348,6 +348,7 @@ struct vm_area_struct {
 	struct mempolicy *vm_policy;	/* NUMA policy for the VMA */
 #endif
 	struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
+	void *suse_kabi_padding;
 } __randomize_layout;
 
 struct core_thread {
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -559,6 +559,7 @@ struct zone {
 	/* Zone statistics */
 	atomic_long_t		vm_stat[NR_VM_ZONE_STAT_ITEMS];
 	atomic_long_t		vm_numa_stat[NR_VM_NUMA_STAT_ITEMS];
+	void *suse_kabi_padding;
 } ____cacheline_internodealigned_in_smp;
 
 enum pgdat_flags {
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -508,6 +508,7 @@ struct module {
 	struct error_injection_entry *ei_funcs;
 	unsigned int num_ei_funcs;
 #endif
+	void *suse_kabi_padding;
 } ____cacheline_aligned __randomize_layout;
 #ifndef MODULE_ARCH_INIT
 #define MODULE_ARCH_INIT {}
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -69,6 +69,7 @@ struct vfsmount {
 	struct dentry *mnt_root;	/* root of the mounted tree */
 	struct super_block *mnt_sb;	/* pointer to superblock */
 	int mnt_flags;
+	void *suse_kabi_padding;
 } __randomize_layout;
 
 struct file; /* forward dec */
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -507,6 +507,7 @@ struct sched_rt_entity {
 	/* rq "owned" by this entity/group: */
 	struct rt_rq			*my_q;
 #endif
+	void *suse_kabi_padding;
 } __randomize_layout;
 
 struct sched_dl_entity {
@@ -1273,6 +1274,7 @@ struct task_struct {
 	unsigned long			lowest_stack;
 	unsigned long			prev_lowest_stack;
 #endif
+	void				*suse_kabi_padding;
 
 	/*
 	 * New fields for task_struct should be added above here, so that
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -233,6 +233,7 @@ struct signal_struct {
 	struct mutex cred_guard_mutex;	/* guard against foreign influences on
 					 * credential calculations
 					 * (notably. ptrace) */
+	void *suse_kabi_padding;
 } __randomize_layout;
 
 /*
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -506,6 +506,7 @@ struct sock {
 							struct sk_buff *skb);
 #endif
 	void                    (*sk_destruct)(struct sock *sk);
+	void			*suse_kabi_padding;
 	struct sock_reuseport __rcu	*sk_reuseport_cb;
 #ifdef CONFIG_BPF_SYSCALL
 	struct bpf_sk_storage __rcu	*sk_bpf_storage;