[patch V2 2/4] atomics: Provide atomic_add_and_negative() variants

From: Thomas Gleixner
Date: Tue Mar 07 2023 - 07:58:08 EST

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atomic_add_and_negative() does not provide the relaxed/acquire/release
variants.

Provide them in preparation for a new scalable reference count algorithm.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
V2: New patch
---
include/linux/atomic/atomic-arch-fallback.h | 200 +++++++++++++++++++++++++++-
include/linux/atomic/atomic-instrumented.h | 68 +++++++++
include/linux/atomic/atomic-long.h | 38 +++++
scripts/atomic/atomics.tbl | 2
scripts/atomic/fallbacks/add_negative | 4
5 files changed, 306 insertions(+), 6 deletions(-)

--- a/include/linux/atomic/atomic-arch-fallback.h
+++ b/include/linux/atomic/atomic-arch-fallback.h
@@ -1208,6 +1208,13 @@ arch_atomic_inc_and_test(atomic_t *v)
#define arch_atomic_inc_and_test arch_atomic_inc_and_test
#endif

+#ifndef arch_atomic_add_negative_relaxed
+#ifdef arch_atomic_add_negative
+#define arch_atomic_add_negative_acquire arch_atomic_add_negative
+#define arch_atomic_add_negative_release arch_atomic_add_negative
+#define arch_atomic_add_negative_relaxed arch_atomic_add_negative
+#endif /* arch_atomic_add_negative */
+
#ifndef arch_atomic_add_negative
/**
* arch_atomic_add_negative - add and test if negative
@@ -1226,6 +1233,98 @@ arch_atomic_add_negative(int i, atomic_t
#define arch_atomic_add_negative arch_atomic_add_negative
#endif

+#ifndef arch_atomic_add_negative_acquire
+/**
+ * arch_atomic_add_negative - add and test if negative
+ * @i: integer value to add
+ * @v: pointer of type atomic_t
+ *
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static __always_inline bool
+arch_atomic_add_negative_acquire(int i, atomic_t *v)
+{
+ return arch_atomic_add_return_acquire(i, v) < 0;
+}
+#define arch_atomic_add_negative_acquire arch_atomic_add_negative_acquire
+#endif
+
+#ifndef arch_atomic_add_negative_release
+/**
+ * arch_atomic_add_negative - add and test if negative
+ * @i: integer value to add
+ * @v: pointer of type atomic_t
+ *
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static __always_inline bool
+arch_atomic_add_negative_release(int i, atomic_t *v)
+{
+ return arch_atomic_add_return_release(i, v) < 0;
+}
+#define arch_atomic_add_negative_release arch_atomic_add_negative_release
+#endif
+
+#ifndef arch_atomic_add_negative_relaxed
+/**
+ * arch_atomic_add_negative - add and test if negative
+ * @i: integer value to add
+ * @v: pointer of type atomic_t
+ *
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static __always_inline bool
+arch_atomic_add_negative_relaxed(int i, atomic_t *v)
+{
+ return arch_atomic_add_return_relaxed(i, v) < 0;
+}
+#define arch_atomic_add_negative_relaxed arch_atomic_add_negative_relaxed
+#endif
+
+#else /* arch_atomic_add_negative_relaxed */
+
+#ifndef arch_atomic_add_negative_acquire
+static __always_inline bool
+arch_atomic_add_negative_acquire(int i, atomic_t *v)
+{
+ bool ret = arch_atomic_add_negative_relaxed(i, v);
+ __atomic_acquire_fence();
+ return ret;
+}
+#define arch_atomic_add_negative_acquire arch_atomic_add_negative_acquire
+#endif
+
+#ifndef arch_atomic_add_negative_release
+static __always_inline bool
+arch_atomic_add_negative_release(int i, atomic_t *v)
+{
+ __atomic_release_fence();
+ return arch_atomic_add_negative_relaxed(i, v);
+}
+#define arch_atomic_add_negative_release arch_atomic_add_negative_release
+#endif
+
+#ifndef arch_atomic_add_negative
+static __always_inline bool
+arch_atomic_add_negative(int i, atomic_t *v)
+{
+ bool ret;
+ __atomic_pre_full_fence();
+ ret = arch_atomic_add_negative_relaxed(i, v);
+ __atomic_post_full_fence();
+ return ret;
+}
+#define arch_atomic_add_negative arch_atomic_add_negative
+#endif
+
+#endif /* arch_atomic_add_negative_relaxed */
+
#ifndef arch_atomic_fetch_add_unless
/**
* arch_atomic_fetch_add_unless - add unless the number is already a given value
@@ -2329,6 +2428,13 @@ arch_atomic64_inc_and_test(atomic64_t *v
#define arch_atomic64_inc_and_test arch_atomic64_inc_and_test
#endif

+#ifndef arch_atomic64_add_negative_relaxed
+#ifdef arch_atomic64_add_negative
+#define arch_atomic64_add_negative_acquire arch_atomic64_add_negative
+#define arch_atomic64_add_negative_release arch_atomic64_add_negative
+#define arch_atomic64_add_negative_relaxed arch_atomic64_add_negative
+#endif /* arch_atomic64_add_negative */
+
#ifndef arch_atomic64_add_negative
/**
* arch_atomic64_add_negative - add and test if negative
@@ -2347,6 +2453,98 @@ arch_atomic64_add_negative(s64 i, atomic
#define arch_atomic64_add_negative arch_atomic64_add_negative
#endif

+#ifndef arch_atomic64_add_negative_acquire
+/**
+ * arch_atomic64_add_negative - add and test if negative
+ * @i: integer value to add
+ * @v: pointer of type atomic64_t
+ *
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static __always_inline bool
+arch_atomic64_add_negative_acquire(s64 i, atomic64_t *v)
+{
+ return arch_atomic64_add_return_acquire(i, v) < 0;
+}
+#define arch_atomic64_add_negative_acquire arch_atomic64_add_negative_acquire
+#endif
+
+#ifndef arch_atomic64_add_negative_release
+/**
+ * arch_atomic64_add_negative - add and test if negative
+ * @i: integer value to add
+ * @v: pointer of type atomic64_t
+ *
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static __always_inline bool
+arch_atomic64_add_negative_release(s64 i, atomic64_t *v)
+{
+ return arch_atomic64_add_return_release(i, v) < 0;
+}
+#define arch_atomic64_add_negative_release arch_atomic64_add_negative_release
+#endif
+
+#ifndef arch_atomic64_add_negative_relaxed
+/**
+ * arch_atomic64_add_negative - add and test if negative
+ * @i: integer value to add
+ * @v: pointer of type atomic64_t
+ *
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static __always_inline bool
+arch_atomic64_add_negative_relaxed(s64 i, atomic64_t *v)
+{
+ return arch_atomic64_add_return_relaxed(i, v) < 0;
+}
+#define arch_atomic64_add_negative_relaxed arch_atomic64_add_negative_relaxed
+#endif
+
+#else /* arch_atomic64_add_negative_relaxed */
+
+#ifndef arch_atomic64_add_negative_acquire
+static __always_inline bool
+arch_atomic64_add_negative_acquire(s64 i, atomic64_t *v)
+{
+ bool ret = arch_atomic64_add_negative_relaxed(i, v);
+ __atomic_acquire_fence();
+ return ret;
+}
+#define arch_atomic64_add_negative_acquire arch_atomic64_add_negative_acquire
+#endif
+
+#ifndef arch_atomic64_add_negative_release
+static __always_inline bool
+arch_atomic64_add_negative_release(s64 i, atomic64_t *v)
+{
+ __atomic_release_fence();
+ return arch_atomic64_add_negative_relaxed(i, v);
+}
+#define arch_atomic64_add_negative_release arch_atomic64_add_negative_release
+#endif
+
+#ifndef arch_atomic64_add_negative
+static __always_inline bool
+arch_atomic64_add_negative(s64 i, atomic64_t *v)
+{
+ bool ret;
+ __atomic_pre_full_fence();
+ ret = arch_atomic64_add_negative_relaxed(i, v);
+ __atomic_post_full_fence();
+ return ret;
+}
+#define arch_atomic64_add_negative arch_atomic64_add_negative
+#endif
+
+#endif /* arch_atomic64_add_negative_relaxed */
+
#ifndef arch_atomic64_fetch_add_unless
/**
* arch_atomic64_fetch_add_unless - add unless the number is already a given value
@@ -2456,4 +2654,4 @@ arch_atomic64_dec_if_positive(atomic64_t
#endif

#endif /* _LINUX_ATOMIC_FALLBACK_H */
-// b5e87bdd5ede61470c29f7a7e4de781af3770f09
+// 63bcc1a53125d4eca5e659892e10615f00f9abf8
--- a/include/linux/atomic/atomic-instrumented.h
+++ b/include/linux/atomic/atomic-instrumented.h
@@ -592,6 +592,28 @@ atomic_add_negative(int i, atomic_t *v)
return arch_atomic_add_negative(i, v);
}

+static __always_inline bool
+atomic_add_negative_acquire(int i, atomic_t *v)
+{
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic_add_negative_acquire(i, v);
+}
+
+static __always_inline bool
+atomic_add_negative_release(int i, atomic_t *v)
+{
+ kcsan_release();
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic_add_negative_release(i, v);
+}
+
+static __always_inline bool
+atomic_add_negative_relaxed(int i, atomic_t *v)
+{
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic_add_negative_relaxed(i, v);
+}
+
static __always_inline int
atomic_fetch_add_unless(atomic_t *v, int a, int u)
{
@@ -1211,6 +1233,28 @@ atomic64_add_negative(s64 i, atomic64_t
return arch_atomic64_add_negative(i, v);
}

+static __always_inline bool
+atomic64_add_negative_acquire(s64 i, atomic64_t *v)
+{
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic64_add_negative_acquire(i, v);
+}
+
+static __always_inline bool
+atomic64_add_negative_release(s64 i, atomic64_t *v)
+{
+ kcsan_release();
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic64_add_negative_release(i, v);
+}
+
+static __always_inline bool
+atomic64_add_negative_relaxed(s64 i, atomic64_t *v)
+{
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic64_add_negative_relaxed(i, v);
+}
+
static __always_inline s64
atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
{
@@ -1830,6 +1874,28 @@ atomic_long_add_negative(long i, atomic_
return arch_atomic_long_add_negative(i, v);
}

+static __always_inline bool
+atomic_long_add_negative_acquire(long i, atomic_long_t *v)
+{
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic_long_add_negative_acquire(i, v);
+}
+
+static __always_inline bool
+atomic_long_add_negative_release(long i, atomic_long_t *v)
+{
+ kcsan_release();
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic_long_add_negative_release(i, v);
+}
+
+static __always_inline bool
+atomic_long_add_negative_relaxed(long i, atomic_long_t *v)
+{
+ instrument_atomic_read_write(v, sizeof(*v));
+ return arch_atomic_long_add_negative_relaxed(i, v);
+}
+
static __always_inline long
atomic_long_fetch_add_unless(atomic_long_t *v, long a, long u)
{
@@ -2083,4 +2149,4 @@ atomic_long_dec_if_positive(atomic_long_
})

#endif /* _LINUX_ATOMIC_INSTRUMENTED_H */
-// 764f741eb77a7ad565dc8d99ce2837d5542e8aee
+// 1b485de9cbaa4900de59e14ee2084357eaeb1c3a
--- a/include/linux/atomic/atomic-long.h
+++ b/include/linux/atomic/atomic-long.h
@@ -479,6 +479,24 @@ arch_atomic_long_add_negative(long i, at
return arch_atomic64_add_negative(i, v);
}

+static __always_inline bool
+arch_atomic_long_add_negative_acquire(long i, atomic_long_t *v)
+{
+ return arch_atomic64_add_negative_acquire(i, v);
+}
+
+static __always_inline bool
+arch_atomic_long_add_negative_release(long i, atomic_long_t *v)
+{
+ return arch_atomic64_add_negative_release(i, v);
+}
+
+static __always_inline bool
+arch_atomic_long_add_negative_relaxed(long i, atomic_long_t *v)
+{
+ return arch_atomic64_add_negative_relaxed(i, v);
+}
+
static __always_inline long
arch_atomic_long_fetch_add_unless(atomic_long_t *v, long a, long u)
{
@@ -973,6 +991,24 @@ arch_atomic_long_add_negative(long i, at
return arch_atomic_add_negative(i, v);
}

+static __always_inline bool
+arch_atomic_long_add_negative_acquire(long i, atomic_long_t *v)
+{
+ return arch_atomic_add_negative_acquire(i, v);
+}
+
+static __always_inline bool
+arch_atomic_long_add_negative_release(long i, atomic_long_t *v)
+{
+ return arch_atomic_add_negative_release(i, v);
+}
+
+static __always_inline bool
+arch_atomic_long_add_negative_relaxed(long i, atomic_long_t *v)
+{
+ return arch_atomic_add_negative_relaxed(i, v);
+}
+
static __always_inline long
arch_atomic_long_fetch_add_unless(atomic_long_t *v, long a, long u)
{
@@ -1011,4 +1047,4 @@ arch_atomic_long_dec_if_positive(atomic_

#endif /* CONFIG_64BIT */
#endif /* _LINUX_ATOMIC_LONG_H */
-// e8f0e08ff072b74d180eabe2ad001282b38c2c88
+// a194c07d7d2f4b0e178d3c118c919775d5d65f50
--- a/scripts/atomic/atomics.tbl
+++ b/scripts/atomic/atomics.tbl
@@ -33,7 +33,7 @@ try_cmpxchg B v p:old i:new
sub_and_test b i v
dec_and_test b v
inc_and_test b v
-add_negative b i v
+add_negative B i v
add_unless fb v i:a i:u
inc_not_zero b v
inc_unless_negative b v
--- a/scripts/atomic/fallbacks/add_negative
+++ b/scripts/atomic/fallbacks/add_negative
@@ -9,8 +9,8 @@ cat <<EOF
* result is greater than or equal to zero.
*/
static __always_inline bool
-arch_${atomic}_add_negative(${int} i, ${atomic}_t *v)
+arch_${atomic}_add_negative${order}(${int} i, ${atomic}_t *v)
{
- return arch_${atomic}_add_return(i, v) < 0;
+ return arch_${atomic}_add_return${order}(i, v) < 0;
}
EOF

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