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jump_label: remove bug.h, atomic.h dependencies for HAVE_JUMP_LABEL 

The current jump_label.h includes bug.h for things such as WARN_ON().
This makes the header problematic for inclusion by kernel.h or any
headers that kernel.h includes, since bug.h includes kernel.h (circular
dependency).  The inclusion of atomic.h is similarly problematic.  Thus,
this should make jump_label.h 'includable' from most places.

Link: http://lkml.kernel.org/r/7060ce35ddd0d20b33bf170685e6b0fab816bdf2.1467837322.git.jbaron@akamai.com
Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
steinar/wifi_calib_4_9_kernel
Jason Baron 2016-08-03 13:46:36 -07:00 committed by Linus Torvalds
parent ddb4530601
commit 1f69bf9c61
2 changed files with 76 additions and 23 deletions
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46
include/linux/jump_label.h
View File

@ -76,7 +76,6 @@
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/bug.h>
extern bool static_key_initialized;
@ -115,20 +114,8 @@ enum jump_label_type {
struct module;
#include <linux/atomic.h>
#ifdef HAVE_JUMP_LABEL
static inline int static_key_count(struct static_key *key)
{
/*
* -1 means the first static_key_slow_inc() is in progress.
* static_key_enabled() must return true, so return 1 here.
*/
int n = atomic_read(&key->enabled);
return n >= 0 ? n : 1;
}
#define JUMP_TYPE_FALSE 0UL
#define JUMP_TYPE_TRUE 1UL
#define JUMP_TYPE_MASK 1UL
@ -157,16 +144,29 @@ extern int jump_label_text_reserved(void *start, void *end);
extern void static_key_slow_inc(struct static_key *key);
extern void static_key_slow_dec(struct static_key *key);
extern void jump_label_apply_nops(struct module *mod);
extern int static_key_count(struct static_key *key);
extern void static_key_enable(struct static_key *key);
extern void static_key_disable(struct static_key *key);
/*
* We should be using ATOMIC_INIT() for initializing .enabled, but
* the inclusion of atomic.h is problematic for inclusion of jump_label.h
* in 'low-level' headers. Thus, we are initializing .enabled with a
* raw value, but have added a BUILD_BUG_ON() to catch any issues in
* jump_label_init() see: kernel/jump_label.c.
*/
#define STATIC_KEY_INIT_TRUE \
{ .enabled = ATOMIC_INIT(1), \
{ .enabled = { 1 }, \
.entries = (void *)JUMP_TYPE_TRUE }
#define STATIC_KEY_INIT_FALSE \
{ .enabled = ATOMIC_INIT(0), \
{ .enabled = { 0 }, \
.entries = (void *)JUMP_TYPE_FALSE }
#else /* !HAVE_JUMP_LABEL */
#include <linux/atomic.h>
#include <linux/bug.h>
static inline int static_key_count(struct static_key *key)
{
return atomic_read(&key->enabled);
@ -216,14 +216,6 @@ static inline int jump_label_apply_nops(struct module *mod)
return 0;
}
#define STATIC_KEY_INIT_TRUE { .enabled = ATOMIC_INIT(1) }
#define STATIC_KEY_INIT_FALSE { .enabled = ATOMIC_INIT(0) }
#endif /* HAVE_JUMP_LABEL */
#define STATIC_KEY_INIT STATIC_KEY_INIT_FALSE
#define jump_label_enabled static_key_enabled
static inline void static_key_enable(struct static_key *key)
{
int count = static_key_count(key);
@ -244,6 +236,14 @@ static inline void static_key_disable(struct static_key *key)
static_key_slow_dec(key);
}
#define STATIC_KEY_INIT_TRUE { .enabled = ATOMIC_INIT(1) }
#define STATIC_KEY_INIT_FALSE { .enabled = ATOMIC_INIT(0) }
#endif /* HAVE_JUMP_LABEL */
#define STATIC_KEY_INIT STATIC_KEY_INIT_FALSE
#define jump_label_enabled static_key_enabled
/* -------------------------------------------------------------------------- */
/*

53
kernel/jump_label.c
View File

@ -14,6 +14,7 @@
#include <linux/err.h>
#include <linux/static_key.h>
#include <linux/jump_label_ratelimit.h>
#include <linux/bug.h>
#ifdef HAVE_JUMP_LABEL
@ -56,6 +57,49 @@ jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
static void jump_label_update(struct static_key *key);
/*
* There are similar definitions for the !HAVE_JUMP_LABEL case in jump_label.h.
* The use of 'atomic_read()' requires atomic.h and its problematic for some
* kernel headers such as kernel.h and others. Since static_key_count() is not
* used in the branch statements as it is for the !HAVE_JUMP_LABEL case its ok
* to have it be a function here. Similarly, for 'static_key_enable()' and
* 'static_key_disable()', which require bug.h. This should allow jump_label.h
* to be included from most/all places for HAVE_JUMP_LABEL.
*/
int static_key_count(struct static_key *key)
{
/*
* -1 means the first static_key_slow_inc() is in progress.
* static_key_enabled() must return true, so return 1 here.
*/
int n = atomic_read(&key->enabled);
return n >= 0 ? n : 1;
}
EXPORT_SYMBOL_GPL(static_key_count);
void static_key_enable(struct static_key *key)
{
int count = static_key_count(key);
WARN_ON_ONCE(count < 0 || count > 1);
if (!count)
static_key_slow_inc(key);
}
EXPORT_SYMBOL_GPL(static_key_enable);
void static_key_disable(struct static_key *key)
{
int count = static_key_count(key);
WARN_ON_ONCE(count < 0 || count > 1);
if (count)
static_key_slow_dec(key);
}
EXPORT_SYMBOL_GPL(static_key_disable);
void static_key_slow_inc(struct static_key *key)
{
int v, v1;
@ -235,6 +279,15 @@ void __init jump_label_init(void)
struct static_key *key = NULL;
struct jump_entry *iter;
/*
* Since we are initializing the static_key.enabled field with
* with the 'raw' int values (to avoid pulling in atomic.h) in
* jump_label.h, let's make sure that is safe. There are only two
* cases to check since we initialize to 0 or 1.
*/
BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0);
BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1);
jump_label_lock();
jump_label_sort_entries(iter_start, iter_stop);