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.

Will Deacon committed 6 years ago

Commit fb041bb1 parent 65b008511 files · +59 −308Browse files

Showing the changes to include/linux (1 of 11 files). Show all

Unified · Split

include/linux/refcount.h+58−100

@@ -1,64 +1,4 @@
1	1	/* SPDX-License-Identifier: GPL-2.0 */
2		−#ifndef _LINUX_REFCOUNT_H
3		−#define _LINUX_REFCOUNT_H
4		−
5		−#include <linux/atomic.h>
6		−#include <linux/compiler.h>
7		−#include <linux/limits.h>
8		−#include <linux/spinlock_types.h>
9		−
10		−struct mutex;
11		−
12		−/**
13		− * struct refcount_t - variant of atomic_t specialized for reference counts
14		− * @refs: atomic_t counter field
15		− *
16		− * The counter saturates at REFCOUNT_SATURATED and will not move once
17		− * there. This avoids wrapping the counter and causing 'spurious'
18		− * use-after-free bugs.
19		− */
20		−typedef struct refcount_struct {
21		− atomic_t refs;
22		−} refcount_t;
23		−
24		−#define REFCOUNT_INIT(n) { .refs = ATOMIC_INIT(n), }
25		−#define REFCOUNT_MAX INT_MAX
26		−#define REFCOUNT_SATURATED (INT_MIN / 2)
27		−
28		−enum refcount_saturation_type {
29		− REFCOUNT_ADD_NOT_ZERO_OVF,
30		− REFCOUNT_ADD_OVF,
31		− REFCOUNT_ADD_UAF,
32		− REFCOUNT_SUB_UAF,
33		− REFCOUNT_DEC_LEAK,
34		−};
35		−
36		−void refcount_warn_saturate(refcount_t *r, enum refcount_saturation_type t);
37		−
38		−/**
39		− * refcount_set - set a refcount's value
40		− * @r: the refcount
41		− * @n: value to which the refcount will be set
42		− */
43		−static inline void refcount_set(refcount_t *r, int n)
44		−{
45		− atomic_set(&r->refs, n);
46		−}
47		−
48		−/**
49		− * refcount_read - get a refcount's value
50		− * @r: the refcount
51		− *
52		− * Return: the refcount's value
53		− */
54		−static inline unsigned int refcount_read(const refcount_t *r)
55		−{
56		− return atomic_read(&r->refs);
57		−}
58		−
59		−#ifdef CONFIG_REFCOUNT_FULL
60		−#include <linux/bug.h>
61		−
62	2	/*
63	3	* Variant of atomic_t specialized for reference counts.
64	4	*
@@ -136,6 +76,64 @@ static inline unsigned int refcount_read(const refcount_t *r) · 71 unmodified lines
136	76	*
137	77	*/
138	78
	79	+#ifndef _LINUX_REFCOUNT_H
	80	+#define _LINUX_REFCOUNT_H
	81	+
	82	+#include <linux/atomic.h>
	83	+#include <linux/bug.h>
	84	+#include <linux/compiler.h>
	85	+#include <linux/limits.h>
	86	+#include <linux/spinlock_types.h>
	87	+
	88	+struct mutex;
	89	+
	90	+/**
	91	+ * struct refcount_t - variant of atomic_t specialized for reference counts
	92	+ * @refs: atomic_t counter field
	93	+ *
	94	+ * The counter saturates at REFCOUNT_SATURATED and will not move once
	95	+ * there. This avoids wrapping the counter and causing 'spurious'
	96	+ * use-after-free bugs.
	97	+ */
	98	+typedef struct refcount_struct {
	99	+ atomic_t refs;
	100	+} refcount_t;
	101	+
	102	+#define REFCOUNT_INIT(n) { .refs = ATOMIC_INIT(n), }
	103	+#define REFCOUNT_MAX INT_MAX
	104	+#define REFCOUNT_SATURATED (INT_MIN / 2)
	105	+
	106	+enum refcount_saturation_type {
	107	+ REFCOUNT_ADD_NOT_ZERO_OVF,
	108	+ REFCOUNT_ADD_OVF,
	109	+ REFCOUNT_ADD_UAF,
	110	+ REFCOUNT_SUB_UAF,
	111	+ REFCOUNT_DEC_LEAK,
	112	+};
	113	+
	114	+void refcount_warn_saturate(refcount_t *r, enum refcount_saturation_type t);
	115	+
	116	+/**
	117	+ * refcount_set - set a refcount's value
	118	+ * @r: the refcount
	119	+ * @n: value to which the refcount will be set
	120	+ */
	121	+static inline void refcount_set(refcount_t *r, int n)
	122	+{
	123	+ atomic_set(&r->refs, n);
	124	+}
	125	+
	126	+/**
	127	+ * refcount_read - get a refcount's value
	128	+ * @r: the refcount
	129	+ *
	130	+ * Return: the refcount's value
	131	+ */
	132	+static inline unsigned int refcount_read(const refcount_t *r)
	133	+{
	134	+ return atomic_read(&r->refs);
	135	+}
	136	+
139	137	/**
140	138	* refcount_add_not_zero - add a value to a refcount unless it is 0
141	139	* @i: the value to add to the refcount
@@ -298,46 +296,6 @@ static inline void refcount_dec(refcount_t *r) · 156 unmodified lines
298	296	if (unlikely(atomic_fetch_sub_release(1, &r->refs) <= 1))
299	297	refcount_warn_saturate(r, REFCOUNT_DEC_LEAK);
300	298	}
301		−#else /* CONFIG_REFCOUNT_FULL */
302		−# ifdef CONFIG_ARCH_HAS_REFCOUNT
303		−# include <asm/refcount.h>
304		−# else
305		−static inline __must_check bool refcount_add_not_zero(int i, refcount_t *r)
306		−{
307		− return atomic_add_unless(&r->refs, i, 0);
308		−}
309		−
310		−static inline void refcount_add(int i, refcount_t *r)
311		−{
312		− atomic_add(i, &r->refs);
313		−}
314		−
315		−static inline __must_check bool refcount_inc_not_zero(refcount_t *r)
316		−{
317		− return atomic_add_unless(&r->refs, 1, 0);
318		−}
319		−
320		−static inline void refcount_inc(refcount_t *r)
321		−{
322		− atomic_inc(&r->refs);
323		−}
324		−
325		−static inline __must_check bool refcount_sub_and_test(int i, refcount_t *r)
326		−{
327		− return atomic_sub_and_test(i, &r->refs);
328		−}
329		−
330		−static inline __must_check bool refcount_dec_and_test(refcount_t *r)
331		−{
332		− return atomic_dec_and_test(&r->refs);
333		−}
334		−
335		−static inline void refcount_dec(refcount_t *r)
336		−{
337		− atomic_dec(&r->refs);
338		−}
339		−# endif /* !CONFIG_ARCH_HAS_REFCOUNT */
340		−#endif /* !CONFIG_REFCOUNT_FULL */
341	299
342	300	extern __must_check bool refcount_dec_if_one(refcount_t *r);
343	301	extern __must_check bool refcount_dec_not_one(refcount_t *r);

locking/refcount: Consolidate implementations of refcount_t

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