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34 #ifndef _RTE_RWLOCK_H_
35 #define _RTE_RWLOCK_H_
40 * RTE Read-Write Locks
42 * This file defines an API for read-write locks. The lock is used to
43 * protect data that allows multiple readers in parallel, but only
44 * one writer. All readers are blocked until the writer is finished
53 #include <rte_common.h>
54 #include <rte_atomic.h>
57 * The rte_rwlock_t type.
59 * cnt is -1 when write lock is held, and > 0 when read locks are held.
62 volatile int32_t cnt; /**< -1 when W lock held, > 0 when R locks held. */
66 * A static rwlock initializer.
68 #define RTE_RWLOCK_INITIALIZER { 0 }
71 * Initialize the rwlock to an unlocked state.
74 * A pointer to the rwlock structure.
77 rte_rwlock_init(rte_rwlock_t *rwl)
83 * Take a read lock. Loop until the lock is held.
86 * A pointer to a rwlock structure.
89 rte_rwlock_read_lock(rte_rwlock_t *rwl)
94 while (success == 0) {
96 /* write lock is held */
101 success = rte_atomic32_cmpset((volatile uint32_t *)&rwl->cnt,
107 * Release a read lock.
110 * A pointer to the rwlock structure.
113 rte_rwlock_read_unlock(rte_rwlock_t *rwl)
115 rte_atomic32_dec((rte_atomic32_t *)(intptr_t)&rwl->cnt);
119 * Take a write lock. Loop until the lock is held.
122 * A pointer to a rwlock structure.
125 rte_rwlock_write_lock(rte_rwlock_t *rwl)
130 while (success == 0) {
137 success = rte_atomic32_cmpset((volatile uint32_t *)&rwl->cnt,
143 * Release a write lock.
146 * A pointer to a rwlock structure.
149 rte_rwlock_write_unlock(rte_rwlock_t *rwl)
151 rte_atomic32_inc((rte_atomic32_t *)(intptr_t)&rwl->cnt);
155 * Try to execute critical section in a hardware memory transaction, if it
156 * fails or not available take a read lock
158 * NOTE: An attempt to perform a HW I/O operation inside a hardware memory
159 * transaction always aborts the transaction since the CPU is not able to
160 * roll-back should the transaction fail. Therefore, hardware transactional
161 * locks are not advised to be used around rte_eth_rx_burst() and
162 * rte_eth_tx_burst() calls.
165 * A pointer to a rwlock structure.
168 rte_rwlock_read_lock_tm(rte_rwlock_t *rwl);
171 * Commit hardware memory transaction or release the read lock if the lock is used as a fall-back
174 * A pointer to the rwlock structure.
177 rte_rwlock_read_unlock_tm(rte_rwlock_t *rwl);
180 * Try to execute critical section in a hardware memory transaction, if it
181 * fails or not available take a write lock
183 * NOTE: An attempt to perform a HW I/O operation inside a hardware memory
184 * transaction always aborts the transaction since the CPU is not able to
185 * roll-back should the transaction fail. Therefore, hardware transactional
186 * locks are not advised to be used around rte_eth_rx_burst() and
187 * rte_eth_tx_burst() calls.
190 * A pointer to a rwlock structure.
193 rte_rwlock_write_lock_tm(rte_rwlock_t *rwl);
196 * Commit hardware memory transaction or release the write lock if the lock is used as a fall-back
199 * A pointer to a rwlock structure.
202 rte_rwlock_write_unlock_tm(rte_rwlock_t *rwl);
208 #endif /* _RTE_RWLOCK_H_ */