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authorWill Deacon <will@kernel.org>2019-11-21 14:59:00 +0300
committerIngo Molnar <mingo@kernel.org>2019-11-25 11:15:32 +0300
commitfb041bb7c0a918b95c6889fc965cdc4a75b4c0ca (patch)
tree5aa81da7df6a7a1374a7d3c42f0a9bde3a3f4722 /include/linux/refcount.h
parent65b008552469f1c37f5e06e0016924502e40b4f5 (diff)
downloadlinux-fb041bb7c0a918b95c6889fc965cdc4a75b4c0ca.tar.xz
locking/refcount: Consolidate implementations of refcount_t
The generic implementation of refcount_t should be good enough for everybody, so remove ARCH_HAS_REFCOUNT and REFCOUNT_FULL entirely, leaving the generic implementation enabled unconditionally. Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> Tested-by: Hanjun Guo <guohanjun@huawei.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191121115902.2551-9-will@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/refcount.h')
-rw-r--r--include/linux/refcount.h158
1 files changed, 58 insertions, 100 deletions
diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index 757d4630115c..0ac50cf62d06 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -1,64 +1,4 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LINUX_REFCOUNT_H
-#define _LINUX_REFCOUNT_H
-
-#include <linux/atomic.h>
-#include <linux/compiler.h>
-#include <linux/limits.h>
-#include <linux/spinlock_types.h>
-
-struct mutex;
-
-/**
- * struct refcount_t - variant of atomic_t specialized for reference counts
- * @refs: atomic_t counter field
- *
- * The counter saturates at REFCOUNT_SATURATED and will not move once
- * there. This avoids wrapping the counter and causing 'spurious'
- * use-after-free bugs.
- */
-typedef struct refcount_struct {
- atomic_t refs;
-} refcount_t;
-
-#define REFCOUNT_INIT(n) { .refs = ATOMIC_INIT(n), }
-#define REFCOUNT_MAX INT_MAX
-#define REFCOUNT_SATURATED (INT_MIN / 2)
-
-enum refcount_saturation_type {
- REFCOUNT_ADD_NOT_ZERO_OVF,
- REFCOUNT_ADD_OVF,
- REFCOUNT_ADD_UAF,
- REFCOUNT_SUB_UAF,
- REFCOUNT_DEC_LEAK,
-};
-
-void refcount_warn_saturate(refcount_t *r, enum refcount_saturation_type t);
-
-/**
- * refcount_set - set a refcount's value
- * @r: the refcount
- * @n: value to which the refcount will be set
- */
-static inline void refcount_set(refcount_t *r, int n)
-{
- atomic_set(&r->refs, n);
-}
-
-/**
- * refcount_read - get a refcount's value
- * @r: the refcount
- *
- * Return: the refcount's value
- */
-static inline unsigned int refcount_read(const refcount_t *r)
-{
- return atomic_read(&r->refs);
-}
-
-#ifdef CONFIG_REFCOUNT_FULL
-#include <linux/bug.h>
-
/*
* Variant of atomic_t specialized for reference counts.
*
@@ -136,6 +76,64 @@ static inline unsigned int refcount_read(const refcount_t *r)
*
*/
+#ifndef _LINUX_REFCOUNT_H
+#define _LINUX_REFCOUNT_H
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/compiler.h>
+#include <linux/limits.h>
+#include <linux/spinlock_types.h>
+
+struct mutex;
+
+/**
+ * struct refcount_t - variant of atomic_t specialized for reference counts
+ * @refs: atomic_t counter field
+ *
+ * The counter saturates at REFCOUNT_SATURATED and will not move once
+ * there. This avoids wrapping the counter and causing 'spurious'
+ * use-after-free bugs.
+ */
+typedef struct refcount_struct {
+ atomic_t refs;
+} refcount_t;
+
+#define REFCOUNT_INIT(n) { .refs = ATOMIC_INIT(n), }
+#define REFCOUNT_MAX INT_MAX
+#define REFCOUNT_SATURATED (INT_MIN / 2)
+
+enum refcount_saturation_type {
+ REFCOUNT_ADD_NOT_ZERO_OVF,
+ REFCOUNT_ADD_OVF,
+ REFCOUNT_ADD_UAF,
+ REFCOUNT_SUB_UAF,
+ REFCOUNT_DEC_LEAK,
+};
+
+void refcount_warn_saturate(refcount_t *r, enum refcount_saturation_type t);
+
+/**
+ * refcount_set - set a refcount's value
+ * @r: the refcount
+ * @n: value to which the refcount will be set
+ */
+static inline void refcount_set(refcount_t *r, int n)
+{
+ atomic_set(&r->refs, n);
+}
+
+/**
+ * refcount_read - get a refcount's value
+ * @r: the refcount
+ *
+ * Return: the refcount's value
+ */
+static inline unsigned int refcount_read(const refcount_t *r)
+{
+ return atomic_read(&r->refs);
+}
+
/**
* refcount_add_not_zero - add a value to a refcount unless it is 0
* @i: the value to add to the refcount
@@ -298,46 +296,6 @@ static inline void refcount_dec(refcount_t *r)
if (unlikely(atomic_fetch_sub_release(1, &r->refs) <= 1))
refcount_warn_saturate(r, REFCOUNT_DEC_LEAK);
}
-#else /* CONFIG_REFCOUNT_FULL */
-# ifdef CONFIG_ARCH_HAS_REFCOUNT
-# include <asm/refcount.h>
-# else
-static inline __must_check bool refcount_add_not_zero(int i, refcount_t *r)
-{
- return atomic_add_unless(&r->refs, i, 0);
-}
-
-static inline void refcount_add(int i, refcount_t *r)
-{
- atomic_add(i, &r->refs);
-}
-
-static inline __must_check bool refcount_inc_not_zero(refcount_t *r)
-{
- return atomic_add_unless(&r->refs, 1, 0);
-}
-
-static inline void refcount_inc(refcount_t *r)
-{
- atomic_inc(&r->refs);
-}
-
-static inline __must_check bool refcount_sub_and_test(int i, refcount_t *r)
-{
- return atomic_sub_and_test(i, &r->refs);
-}
-
-static inline __must_check bool refcount_dec_and_test(refcount_t *r)
-{
- return atomic_dec_and_test(&r->refs);
-}
-
-static inline void refcount_dec(refcount_t *r)
-{
- atomic_dec(&r->refs);
-}
-# endif /* !CONFIG_ARCH_HAS_REFCOUNT */
-#endif /* !CONFIG_REFCOUNT_FULL */
extern __must_check bool refcount_dec_if_one(refcount_t *r);
extern __must_check bool refcount_dec_not_one(refcount_t *r);