Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking and atomic updates from Ingo Molnar:
 "Main changes in this cycle are:

   - Extend atomic primitives with coherent logic op primitives
     (atomic_{or,and,xor}()) and deprecate the old partial APIs
     (atomic_{set,clear}_mask())

     The old ops were incoherent with incompatible signatures across
     architectures and with incomplete support.  Now every architecture
     supports the primitives consistently (by Peter Zijlstra)

   - Generic support for 'relaxed atomics':

       - _acquire/release/relaxed() flavours of xchg(), cmpxchg() and {add,sub}_return()
       - atomic_read_acquire()
       - atomic_set_release()

     This came out of porting qwrlock code to arm64 (by Will Deacon)

   - Clean up the fragile static_key APIs that were causing repeat bugs,
     by introducing a new one:

       DEFINE_STATIC_KEY_TRUE(name);
       DEFINE_STATIC_KEY_FALSE(name);

     which define a key of different types with an initial true/false
     value.

     Then allow:

       static_branch_likely()
       static_branch_unlikely()

     to take a key of either type and emit the right instruction for the
     case.  To be able to know the 'type' of the static key we encode it
     in the jump entry (by Peter Zijlstra)

   - Static key self-tests (by Jason Baron)

   - qrwlock optimizations (by Waiman Long)

   - small futex enhancements (by Davidlohr Bueso)

   - ... and misc other changes"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (63 commits)
  jump_label/x86: Work around asm build bug on older/backported GCCs
  locking, ARM, atomics: Define our SMP atomics in terms of _relaxed() operations
  locking, include/llist: Use linux/atomic.h instead of asm/cmpxchg.h
  locking/qrwlock: Make use of _{acquire|release|relaxed}() atomics
  locking/qrwlock: Implement queue_write_unlock() using smp_store_release()
  locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition
  locking, asm-generic: Add _{relaxed|acquire|release}() variants for 'atomic_long_t'
  locking, asm-generic: Rework atomic-long.h to avoid bulk code duplication
  locking/atomics: Add _{acquire|release|relaxed}() variants of some atomic operations
  locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic
  locking/static_keys: Make verify_keys() static
  jump label, locking/static_keys: Update docs
  locking/static_keys: Provide a selftest
  jump_label: Provide a self-test
  s390/uaccess, locking/static_keys: employ static_branch_likely()
  x86, tsc, locking/static_keys: Employ static_branch_likely()
  locking/static_keys: Add selftest
  locking/static_keys: Add a new static_key interface
  locking/static_keys: Rework update logic
  locking/static_keys: Add static_key_{en,dis}able() helpers
  ...

1 files changed, 225 insertions, 0 deletions

diff --git a/lib/test_static_keys.c b/lib/test_static_keys.c
new file mode 100644
index 000000000000..c61b299e367f
--- /dev/null
+++ b/lib/test_static_keys.c
@@ -0,0 +1,225 @@
+/*
+ * Kernel module for testing static keys.
+ *
+ * Copyright 2015 Akamai Technologies Inc. All Rights Reserved
+ *
+ * Authors:
+ *      Jason Baron       <jbaron@akamai.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/jump_label.h>
+
+/* old keys */
+struct static_key old_true_key	= STATIC_KEY_INIT_TRUE;
+struct static_key old_false_key	= STATIC_KEY_INIT_FALSE;
+
+/* new api */
+DEFINE_STATIC_KEY_TRUE(true_key);
+DEFINE_STATIC_KEY_FALSE(false_key);
+
+/* external */
+extern struct static_key base_old_true_key;
+extern struct static_key base_inv_old_true_key;
+extern struct static_key base_old_false_key;
+extern struct static_key base_inv_old_false_key;
+
+/* new api */
+extern struct static_key_true base_true_key;
+extern struct static_key_true base_inv_true_key;
+extern struct static_key_false base_false_key;
+extern struct static_key_false base_inv_false_key;
+
+
+struct test_key {
+	bool			init_state;
+	struct static_key	*key;
+	bool			(*test_key)(void);
+};
+
+#define test_key_func(key, branch) \
+	({bool func(void) { return branch(key); } func;	})
+
+static void invert_key(struct static_key *key)
+{
+	if (static_key_enabled(key))
+		static_key_disable(key);
+	else
+		static_key_enable(key);
+}
+
+static void invert_keys(struct test_key *keys, int size)
+{
+	struct static_key *previous = NULL;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		if (previous != keys[i].key) {
+			invert_key(keys[i].key);
+			previous = keys[i].key;
+		}
+	}
+}
+
+static int verify_keys(struct test_key *keys, int size, bool invert)
+{
+	int i;
+	bool ret, init;
+
+	for (i = 0; i < size; i++) {
+		ret = static_key_enabled(keys[i].key);
+		init = keys[i].init_state;
+		if (ret != (invert ? !init : init))
+			return -EINVAL;
+		ret = keys[i].test_key();
+		if (static_key_enabled(keys[i].key)) {
+			if (!ret)
+				return -EINVAL;
+		} else {
+			if (ret)
+				return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+static int __init test_static_key_init(void)
+{
+	int ret;
+	int size;
+
+	struct test_key static_key_tests[] = {
+		/* internal keys - old keys */
+		{
+			.init_state	= true,
+			.key		= &old_true_key,
+			.test_key	= test_key_func(&old_true_key, static_key_true),
+		},
+		{
+			.init_state	= false,
+			.key		= &old_false_key,
+			.test_key	= test_key_func(&old_false_key, static_key_false),
+		},
+		/* internal keys - new keys */
+		{
+			.init_state	= true,
+			.key		= &true_key.key,
+			.test_key	= test_key_func(&true_key, static_branch_likely),
+		},
+		{
+			.init_state	= true,
+			.key		= &true_key.key,
+			.test_key	= test_key_func(&true_key, static_branch_unlikely),
+		},
+		{
+			.init_state	= false,
+			.key		= &false_key.key,
+			.test_key	= test_key_func(&false_key, static_branch_likely),
+		},
+		{
+			.init_state	= false,
+			.key		= &false_key.key,
+			.test_key	= test_key_func(&false_key, static_branch_unlikely),
+		},
+		/* external keys - old keys */
+		{
+			.init_state	= true,
+			.key		= &base_old_true_key,
+			.test_key	= test_key_func(&base_old_true_key, static_key_true),
+		},
+		{
+			.init_state	= false,
+			.key		= &base_inv_old_true_key,
+			.test_key	= test_key_func(&base_inv_old_true_key, static_key_true),
+		},
+		{
+			.init_state	= false,
+			.key		= &base_old_false_key,
+			.test_key	= test_key_func(&base_old_false_key, static_key_false),
+		},
+		{
+			.init_state	= true,
+			.key		= &base_inv_old_false_key,
+			.test_key	= test_key_func(&base_inv_old_false_key, static_key_false),
+		},
+		/* external keys - new keys */
+		{
+			.init_state	= true,
+			.key		= &base_true_key.key,
+			.test_key	= test_key_func(&base_true_key, static_branch_likely),
+		},
+		{
+			.init_state	= true,
+			.key		= &base_true_key.key,
+			.test_key	= test_key_func(&base_true_key, static_branch_unlikely),
+		},
+		{
+			.init_state	= false,
+			.key		= &base_inv_true_key.key,
+			.test_key	= test_key_func(&base_inv_true_key, static_branch_likely),
+		},
+		{
+			.init_state	= false,
+			.key		= &base_inv_true_key.key,
+			.test_key	= test_key_func(&base_inv_true_key, static_branch_unlikely),
+		},
+		{
+			.init_state	= false,
+			.key		= &base_false_key.key,
+			.test_key	= test_key_func(&base_false_key, static_branch_likely),
+		},
+		{
+			.init_state	= false,
+			.key		= &base_false_key.key,
+			.test_key	= test_key_func(&base_false_key, static_branch_unlikely),
+		},
+		{
+			.init_state	= true,
+			.key		= &base_inv_false_key.key,
+			.test_key	= test_key_func(&base_inv_false_key, static_branch_likely),
+		},
+		{
+			.init_state	= true,
+			.key		= &base_inv_false_key.key,
+			.test_key	= test_key_func(&base_inv_false_key, static_branch_unlikely),
+		},
+	};
+
+	size = ARRAY_SIZE(static_key_tests);
+
+	ret = verify_keys(static_key_tests, size, false);
+	if (ret)
+		goto out;
+
+	invert_keys(static_key_tests, size);
+	ret = verify_keys(static_key_tests, size, true);
+	if (ret)
+		goto out;
+
+	invert_keys(static_key_tests, size);
+	ret = verify_keys(static_key_tests, size, false);
+	if (ret)
+		goto out;
+	return 0;
+out:
+	return ret;
+}
+
+static void __exit test_static_key_exit(void)
+{
+}
+
+module_init(test_static_key_init);
+module_exit(test_static_key_exit);
+
+MODULE_AUTHOR("Jason Baron <jbaron@akamai.com>");
+MODULE_LICENSE("GPL");