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+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2012 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * version: DPDK.L.1.2.3-3
+ */
+
+#ifndef _RTE_SPINLOCK_H_
+#define _RTE_SPINLOCK_H_
+
+/**
+ * @file
+ *
+ * RTE Spinlocks
+ *
+ * This file defines an API for read-write locks, which are implemented
+ * in an architecture-specific way. This kind of lock simply waits in
+ * a loop repeatedly checking until the lock becomes available.
+ *
+ * All locks must be initialised before use, and only initialised once.
+ *
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <rte_lcore.h>
+
+/**
+ * The rte_spinlock_t type.
+ */
+typedef struct {
+ volatile int locked; /**< lock status 0 = unlocked, 1 = locked */
+} rte_spinlock_t;
+
+/**
+ * A static spinlock initializer.
+ */
+#define RTE_SPINLOCK_INITIALIZER { 0 }
+
+/**
+ * Initialize the spinlock to an unlocked state.
+ *
+ * @param sl
+ * A pointer to the spinlock.
+ */
+static inline void
+rte_spinlock_init(rte_spinlock_t *sl)
+{
+ sl->locked = 0;
+}
+
+/**
+ * Take the spinlock.
+ *
+ * @param sl
+ * A pointer to the spinlock.
+ */
+static inline void
+rte_spinlock_lock(rte_spinlock_t *sl)
+{
+ int lock_val = 1;
+ asm volatile (
+ "1:\n"
+ "xchg %[locked], %[lv]\n"
+ "test %[lv], %[lv]\n"
+ "jz 3f\n"
+ "2:\n"
+ "pause\n"
+ "cmp $0, %[locked]\n"
+ "jnz 2b\n"
+ "jmp 1b\n"
+ "3:\n"
+ : [locked] "=m" (sl->locked), [lv] "=q" (lock_val)
+ : "[lv]" (lock_val)
+ : "memory");
+}
+
+/**
+ * Release the spinlock.
+ *
+ * @param sl
+ * A pointer to the spinlock.
+ */
+static inline void
+rte_spinlock_unlock (rte_spinlock_t *sl)
+{
+ int unlock_val = 0;
+ asm volatile (
+ "xchg %[locked], %[ulv]\n"
+ : [locked] "=m" (sl->locked), [ulv] "=q" (unlock_val)
+ : "[ulv]" (unlock_val)
+ : "memory");
+}
+
+/**
+ * Try to take the lock.
+ *
+ * @param sl
+ * A pointer to the spinlock.
+ * @return
+ * 1 if the lock is successfully taken; 0 otherwise.
+ */
+static inline int
+rte_spinlock_trylock (rte_spinlock_t *sl)
+{
+ int lockval = 1;
+
+ asm volatile (
+ "xchg %[locked], %[lockval]"
+ : [locked] "=m" (sl->locked), [lockval] "=q" (lockval)
+ : "[lockval]" (lockval)
+ : "memory");
+
+ return (lockval == 0);
+}
+
+/**
+ * Test if the lock is taken.
+ *
+ * @param sl
+ * A pointer to the spinlock.
+ * @return
+ * 1 if the lock is currently taken; 0 otherwise.
+ */
+static inline int rte_spinlock_is_locked (rte_spinlock_t *sl)
+{
+ return sl->locked;
+}
+
+/**
+ * The rte_spinlock_recursive_t type.
+ */
+typedef struct {
+ rte_spinlock_t sl; /**< the actual spinlock */
+ volatile int user; /**< core id using lock, -1 for unused */
+ volatile int count; /**< count of time this lock has been called */
+} rte_spinlock_recursive_t;
+
+/**
+ * A static recursive spinlock initializer.
+ */
+#define RTE_SPINLOCK_RECURSIVE_INITIALIZER {RTE_SPINLOCK_INITIALIZER, -1, 0}
+
+/**
+ * Initialize the recursive spinlock to an unlocked state.
+ *
+ * @param slr
+ * A pointer to the recursive spinlock.
+ */
+static inline void rte_spinlock_recursive_init(rte_spinlock_recursive_t *slr)
+{
+ rte_spinlock_init(&slr->sl);
+ slr->user = -1;
+ slr->count = 0;
+}
+
+/**
+ * Take the recursive spinlock.
+ *
+ * @param slr
+ * A pointer to the recursive spinlock.
+ */
+static inline void rte_spinlock_recursive_lock(rte_spinlock_recursive_t *slr)
+{
+ int id = rte_lcore_id();
+
+ if (slr->user != id) {
+ rte_spinlock_lock(&slr->sl);
+ slr->user = id;
+ }
+ slr->count++;
+}
+/**
+ * Release the recursive spinlock.
+ *
+ * @param slr
+ * A pointer to the recursive spinlock.
+ */
+static inline void rte_spinlock_recursive_unlock(rte_spinlock_recursive_t *slr)
+{
+ if (--(slr->count) == 0) {
+ slr->user = -1;
+ rte_spinlock_unlock(&slr->sl);
+ }
+
+}
+
+/**
+ * Try to take the recursive lock.
+ *
+ * @param slr
+ * A pointer to the recursive spinlock.
+ * @return
+ * 1 if the lock is successfully taken; 0 otherwise.
+ */
+static inline int rte_spinlock_recursive_trylock(rte_spinlock_recursive_t *slr)
+{
+ int id = rte_lcore_id();
+
+ if (slr->user != id) {
+ if (rte_spinlock_trylock(&slr->sl) == 0)
+ return 0;
+ slr->user = id;
+ }
+ slr->count++;
+ return 1;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_SPINLOCK_H_ */