[RFC v2 5/6] eal: add atomic bit operations

[Mattias Rönnblom]

Add atomic bit test/set/clear/assign and test-and-set/clear functions.

All atomic bit functions allow (and indeed, require) the caller to
specify a memory order.

RFC v2:
 o Add rte_bit_atomic_test_and_assign() (for consistency).
 o Fix bugs in rte_bit_atomic_test_and_[set|clear]().
 o Use <rte_stdatomics.h> to support MSVC.

Signed-off-by: Mattias Rönnblom <mattias.ronnblom at ericsson.com>
---
 lib/eal/include/rte_bitops.h | 297 +++++++++++++++++++++++++++++++++++
 1 file changed, 297 insertions(+)

diff --git a/lib/eal/include/rte_bitops.h b/lib/eal/include/rte_bitops.h
index a2746e657f..8c38a1ac03 100644
--- a/lib/eal/include/rte_bitops.h
+++ b/lib/eal/include/rte_bitops.h
@@ -21,6 +21,7 @@
 
 #include <rte_compat.h>
 #include <rte_debug.h>
+#include <rte_stdatomic.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -342,6 +343,177 @@ extern "C" {
 		 uint32_t *: __rte_bit_once_assign32,			\
 		 uint64_t *: __rte_bit_once_assign64)(addr, nr, value)
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Test if a particular bit in a word is set with a particular memory
+ * order.
+ *
+ * Test a bit with the resulting memory load ordered as per the
+ * specified memory order.
+ *
+ * @param addr
+ *   A pointer to the word to query.
+ * @param nr
+ *   The index of the bit.
+ * @param memory_order
+ *   The memory order to use. See <rte_stdatomics.h> for details.
+ * @return
+ *   Returns true if the bit is set, and false otherwise.
+ */
+#define rte_bit_atomic_test(addr, nr, memory_order)			\
+	_Generic((addr),						\
+		 uint32_t *: __rte_bit_atomic_test32,			\
+		 uint64_t *: __rte_bit_atomic_test64)(addr, nr, memory_order)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Atomically set bit in word.
+ *
+ * Atomically set bit specified by @c nr in the word pointed to by @c
+ * addr to '1', with the memory ordering as specified by @c
+ * memory_order.
+ *
+ * @param addr
+ *   A pointer to the word to modify.
+ * @param nr
+ *   The index of the bit.
+ * @param memory_order
+ *   The memory order to use. See <rte_stdatomics.h> for details.
+ */
+#define rte_bit_atomic_set(addr, nr, memory_order)			\
+	_Generic((addr),						\
+		 uint32_t *: __rte_bit_atomic_set32,			\
+		 uint64_t *: __rte_bit_atomic_set64)(addr, nr, memory_order)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Atomically clear bit in word.
+ *
+ * Atomically set bit specified by @c nr in the word pointed to by @c
+ * addr to '0', with the memory ordering as specified by @c
+ * memory_order.
+ *
+ * @param addr
+ *   A pointer to the word to modify.
+ * @param nr
+ *   The index of the bit.
+ * @param memory_order
+ *   The memory order to use. See <rte_stdatomics.h> for details.
+ */
+#define rte_bit_atomic_clear(addr, nr, memory_order)			\
+	_Generic((addr),						\
+		 uint32_t *: __rte_bit_atomic_clear32,			\
+		 uint64_t *: __rte_bit_atomic_clear64)(addr, nr, memory_order)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Atomically assign a value to bit in word.
+ *
+ * Atomically set bit specified by @c nr in the word pointed to by @c
+ * addr to the value indicated by @c value, with the memory ordering
+ * as specified with @c memory_order.
+ *
+ * @param addr
+ *   A pointer to the word to modify.
+ * @param nr
+ *   The index of the bit.
+ * @param value
+ *   The new value of the bit - true for '1', or false for '0'.
+ * @param memory_order
+ *   The memory order to use. See <rte_stdatomics.h> for details.
+ */
+#define rte_bit_atomic_assign(addr, nr, value, memory_order)		\
+	_Generic((addr),						\
+		 uint32_t *: __rte_bit_atomic_assign32,			\
+		 uint64_t *: __rte_bit_atomic_assign64)(addr, nr, value, \
+							memory_order)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Atomically test and set a bit in word.
+ *
+ * Atomically test and set bit specified by @c nr in the word pointed
+ * to by @c addr to '1', with the memory ordering as specified with @c
+ * memory_order.
+ *
+ * @param addr
+ *   A pointer to the word to modify.
+ * @param nr
+ *   The index of the bit.
+ * @param memory_order
+ *   The memory order to use. See <rte_stdatomics.h> for details.
+ * @return
+ *   Returns true if the bit was set, and false otherwise.
+ */
+#define rte_bit_atomic_test_and_set(addr, nr, memory_order)		\
+	_Generic((addr),						\
+		 uint32_t *: __rte_bit_atomic_test_and_set32,		\
+		 uint64_t *: __rte_bit_atomic_test_and_set64)(addr, nr,	\
+							      memory_order)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Atomically test and clear a bit in word.
+ *
+ * Atomically test and clear bit specified by @c nr in the word
+ * pointed to by @c addr to '0', with the memory ordering as specified
+ * with @c memory_order.
+ *
+ * @param addr
+ *   A pointer to the word to modify.
+ * @param nr
+ *   The index of the bit.
+ * @param memory_order
+ *   The memory order to use. See <rte_stdatomics.h> for details.
+ * @return
+ *   Returns true if the bit was set, and false otherwise.
+ */
+#define rte_bit_atomic_test_and_clear(addr, nr, memory_order)		\
+	_Generic((addr),						\
+		 uint32_t *: __rte_bit_atomic_test_and_clear32,		\
+		 uint64_t *: __rte_bit_atomic_test_and_clear64)(addr, nr, \
+								memory_order)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Atomically test and assign a bit in word.
+ *
+ * Atomically test and assign bit specified by @c nr in the word
+ * pointed to by @c addr the value specified by @c value, with the
+ * memory ordering as specified with @c memory_order.
+ *
+ * @param addr
+ *   A pointer to the word to modify.
+ * @param nr
+ *   The index of the bit.
+ * @param value
+ *   The new value of the bit - true for '1', or false for '0'.
+ * @param memory_order
+ *   The memory order to use. See <rte_stdatomics.h> for details.
+ * @return
+ *   Returns true if the bit was set, and false otherwise.
+ */
+#define rte_bit_atomic_test_and_assign(addr, nr, value, memory_order)	\
+	_Generic((addr),						\
+		 uint32_t *: __rte_bit_atomic_test_and_assign32,	\
+		 uint64_t *: __rte_bit_atomic_test_and_assign64)(addr, nr, \
+								 value, \
+								 memory_order)
+
 #define __RTE_GEN_BIT_TEST(name, size, qualifier)			\
 	static inline bool						\
 	name(const qualifier uint ## size ## _t *addr, unsigned int nr)	\
@@ -429,6 +601,131 @@ __rte_bit_once_assign64(volatile uint64_t *addr, unsigned int nr, bool value)
 		__rte_bit_once_clear64(addr, nr);
 }
 
+#define __RTE_GEN_BIT_ATOMIC_TEST(size)					\
+	static inline bool						\
+	__rte_bit_atomic_test ## size(const uint ## size ## _t *addr,	\
+				      unsigned int nr, int memory_order) \
+	{								\
+		RTE_ASSERT(nr < size);					\
+									\
+		const RTE_ATOMIC(uint ## size ## _t) *a_addr =		\
+			(const RTE_ATOMIC(uint ## size ## _t) *)addr;	\
+		uint ## size ## _t mask = (uint ## size ## _t)1 << nr;	\
+		return rte_atomic_load_explicit(a_addr, memory_order) & mask; \
+	}
+
+#define __RTE_GEN_BIT_ATOMIC_SET(size)					\
+	static inline void						\
+	__rte_bit_atomic_set ## size(uint ## size ## _t *addr,		\
+				     unsigned int nr, int memory_order)	\
+	{								\
+		RTE_ASSERT(nr < size);					\
+									\
+		RTE_ATOMIC(uint ## size ## _t) *a_addr =		\
+			(RTE_ATOMIC(uint ## size ## _t) *)addr;		\
+		uint ## size ## _t mask = (uint ## size ## _t)1 << nr;	\
+		rte_atomic_fetch_or_explicit(a_addr, mask, memory_order); \
+	}
+
+#define __RTE_GEN_BIT_ATOMIC_CLEAR(size)				\
+	static inline void						\
+	__rte_bit_atomic_clear ## size(uint ## size ## _t *addr,	\
+				       unsigned int nr, int memory_order) \
+	{								\
+		RTE_ASSERT(nr < size);					\
+									\
+		RTE_ATOMIC(uint ## size ## _t) *a_addr =		\
+			(RTE_ATOMIC(uint ## size ## _t) *)addr;		\
+		uint ## size ## _t mask = (uint ## size ## _t)1 << nr;	\
+		rte_atomic_fetch_and_explicit(a_addr, ~mask, memory_order); \
+	}
+
+#define __RTE_GEN_BIT_ATOMIC_ASSIGN(size)				\
+	static inline void						\
+	__rte_bit_atomic_assign ## size(uint ## size ## _t *addr,	\
+					unsigned int nr, bool value,	\
+					int memory_order)		\
+	{								\
+		if (value)						\
+			__rte_bit_atomic_set ## size(addr, nr, memory_order); \
+		else							\
+			__rte_bit_atomic_clear ## size(addr, nr,	\
+						       memory_order);	\
+	}
+
+#define __RTE_GEN_BIT_ATOMIC_TEST_AND_ASSIGN(size)			\
+	static inline bool						\
+	__rte_bit_atomic_test_and_assign ## size(uint ## size ## _t *addr, \
+						 unsigned int nr,	\
+						 bool value,		\
+						 int memory_order)	\
+	{								\
+		RTE_ASSERT(nr < size);					\
+									\
+		RTE_ATOMIC(uint ## size ## _t) *a_addr =		\
+			(RTE_ATOMIC(uint ## size ## _t) *)addr;		\
+		uint ## size ## _t before;				\
+		uint ## size ## _t target;				\
+									\
+		before = rte_atomic_load_explicit(a_addr,		\
+						  rte_memory_order_relaxed); \
+									\
+		do {							\
+			target = before;				\
+			__rte_bit_assign ## size(&target, nr, value);	\
+		} while (!rte_atomic_compare_exchange_weak_explicit(	\
+				a_addr, &before, target,		\
+				rte_memory_order_relaxed,		\
+				memory_order));				\
+		return __rte_bit_test ## size(&before, nr);		\
+	}
+
+#define __RTE_GEN_BIT_ATOMIC_OPS(size)			\
+	__RTE_GEN_BIT_ATOMIC_TEST(size)			\
+	__RTE_GEN_BIT_ATOMIC_SET(size)			\
+	__RTE_GEN_BIT_ATOMIC_CLEAR(size)		\
+	__RTE_GEN_BIT_ATOMIC_ASSIGN(size)		\
+	__RTE_GEN_BIT_ATOMIC_TEST_AND_ASSIGN(size)
+
+__RTE_GEN_BIT_ATOMIC_OPS(32)
+__RTE_GEN_BIT_ATOMIC_OPS(64)
+
+__rte_experimental
+static inline bool
+__rte_bit_atomic_test_and_set32(uint32_t *addr, unsigned int nr,
+			      int memory_order)
+{
+	return __rte_bit_atomic_test_and_assign32(addr, nr, true,
+						  memory_order);
+}
+
+__rte_experimental
+static inline bool
+__rte_bit_atomic_test_and_clear32(uint32_t *addr, unsigned int nr,
+				int memory_order)
+{
+	return __rte_bit_atomic_test_and_assign32(addr, nr, false,
+						  memory_order);
+}
+
+__rte_experimental
+static inline bool
+__rte_bit_atomic_test_and_set64(uint64_t *addr, unsigned int nr,
+			      int memory_order)
+{
+	return __rte_bit_atomic_test_and_assign64(addr, nr, true,
+						  memory_order);
+}
+
+__rte_experimental
+static inline bool
+__rte_bit_atomic_test_and_clear64(uint64_t *addr, unsigned int nr,
+			      int memory_order)
+{
+	return __rte_bit_atomic_test_and_assign64(addr, nr, false,
+						  memory_order);
+}
+
 /*------------------------ 32-bit relaxed operations ------------------------*/
 
 /**
-- 
2.34.1