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[PATCHv3,07/18] atomics: prepare for atomic64_fetch_add_unless()

Message ID 20180618101919.51973-8-mark.rutland@arm.com
State Superseded
Headers show
Series atomics: API cleanups | expand

Commit Message

Mark Rutland June 18, 2018, 10:19 a.m. UTC 
Currently architecture must implement atomic_fetch_add_unless(), with
common code providing atomic_add_unless(). Architectures must also
implement atmic64_add_unless() directly, with no corresponding
atomic64_fetch_add_unless().

This divergenece is unfortunate, and means that the APIs for atomic_t,
atomic64_t, and atomic_long_t differ.

In preparation for unifying things, with architectures providing
atomic64_fetch_add_unless, this patch adds a generic
atomic64_add_unless() which will use atomic64_fetch_add_unless(). The
instrumented atomics are updated to take this case into account.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Albert Ou <albert@sifive.com>
---
 include/asm-generic/atomic-instrumented.h |  9 +++++++++
 include/linux/atomic.h                    | 16 ++++++++++++++++
 2 files changed, 25 insertions(+)

-- 
2.11.0

Comments

Mark Rutland June 18, 2018, 4:10 p.m. UTC | #1 
On Mon, Jun 18, 2018 at 11:19:08AM +0100, Mark Rutland wrote:
> Currently architecture must implement atomic_fetch_add_unless(), with

> common code providing atomic_add_unless(). Architectures must also

> implement atmic64_add_unless() directly, with no corresponding

> atomic64_fetch_add_unless().

> 

> This divergenece is unfortunate, and means that the APIs for atomic_t,

> atomic64_t, and atomic_long_t differ.

> 

> In preparation for unifying things, with architectures providing

> atomic64_fetch_add_unless, this patch adds a generic

> atomic64_add_unless() which will use atomic64_fetch_add_unless(). The

> instrumented atomics are updated to take this case into account.


> +#ifdef arch_atomic64_fetch_add_unless

> +#define atomic64_fetch_add_unless atomic64_fetch_add_unless

> +static __always_inline int atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)


Whoops: s/int/s64/ here

I've fixed that up in my branch.

Thanks,
Mark.
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Patch

diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h
index 1f9b2a767d3c..ab011e1a02fc 100644
--- a/include/asm-generic/atomic-instrumented.h
+++ b/include/asm-generic/atomic-instrumented.h
@@ -93,11 +93,20 @@  static __always_inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
 }
 #endif
 
+#ifdef arch_atomic64_fetch_add_unless
+#define atomic64_fetch_add_unless atomic64_fetch_add_unless
+static __always_inline int atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
+{
+	kasan_check_write(v, sizeof(*v));
+	return arch_atomic64_fetch_add_unless(v, a, u);
+}
+#else
 static __always_inline bool atomic64_add_unless(atomic64_t *v, s64 a, s64 u)
 {
 	kasan_check_write(v, sizeof(*v));
 	return arch_atomic64_add_unless(v, a, u);
 }
+#endif
 
 static __always_inline void atomic_inc(atomic_t *v)
 {
diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index b89ba36cab94..3c03de648007 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -1043,6 +1043,22 @@  static inline int atomic_dec_if_positive(atomic_t *v)
 #endif /* atomic64_try_cmpxchg */
 
 /**
+ * atomic64_add_unless - add unless the number is already a given value
+ * @v: pointer of type atomic_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, if @v was not already @u.
+ * Returns true if the addition was done.
+ */
+#ifdef atomic64_fetch_add_unless
+static inline bool atomic64_add_unless(atomic64_t *v, long long a, long long u)
+{
+	return atomic64_fetch_add_unless(v, a, u) != u;
+}
+#endif
+
+/**
  * atomic64_inc_not_zero - increment unless the number is zero
  * @v: pointer of type atomic64_t
  *