rte_rwlock.h

       Generated automatically by Doxygen for DPDK from the source code.

DPDK                                             Version 24.11.2                                 rte_rwlock.h(3)

       RTE Read-Write Locks

       This file defines an API for read-write locks. The lock is used to protect data that allows multiple
       readers in parallel, but only one writer. All readers are blocked until the writer is finished writing.

       This version does not give preference to readers or writers and does not starve either readers or
       writers.

       See also: https://locklessinc.com/articles/locks/

       Definition in file rte_rwlock.h.

staticvoidrte_rwlock_init(rte_rwlock_t*rwl)[inline],[static]
       Initialize the rwlock to an unlocked state.

       Parametersrwl A pointer to the rwlock structure.

       Definition at line 76 of file rte_rwlock.h.

   staticvoidrte_rwlock_read_lock(rte_rwlock_t*rwl)[inline],[static]
       Take a read lock. Loop until the lock is held.

       Note
           The RW lock isn't recursive, so calling this function on the same lock twice without releasing it
           could potentially result in a deadlock scenario when a write lock is involved.

       Parametersrwl A pointer to a rwlock structure.

       Definition at line 92 of file rte_rwlock.h.

   staticintrte_rwlock_read_trylock(rte_rwlock_t*rwl)[inline],[static]
       Try to take a read lock.

       Parametersrwl A pointer to a rwlock structure.

       Returns

           • zero if the lock is successfully taken

           • -EBUSY if lock could not be acquired for reading because a writer holds the lock

       Definition at line 129 of file rte_rwlock.h.

   staticvoidrte_rwlock_read_unlock(rte_rwlock_t*rwl)[inline],[static]
       Release a read lock.

       Parametersrwl A pointer to the rwlock structure.

       Definition at line 162 of file rte_rwlock.h.

   staticintrte_rwlock_write_trylock(rte_rwlock_t*rwl)[inline],[static]
       Try to take a write lock.

       Parametersrwl A pointer to a rwlock structure.

       Returns

           • zero if the lock is successfully taken

           • -EBUSY  if  lock  could  not  be  acquired for writing because it was already locked for reading or
             writing

       Definition at line 180 of file rte_rwlock.h.

   staticvoidrte_rwlock_write_lock(rte_rwlock_t*rwl)[inline],[static]
       Take a write lock. Loop until the lock is held.

       Parametersrwl A pointer to a rwlock structure.

       Definition at line 202 of file rte_rwlock.h.

   staticvoidrte_rwlock_write_unlock(rte_rwlock_t*rwl)[inline],[static]
       Release a write lock.

       Parametersrwl A pointer to a rwlock structure.

       Definition at line 240 of file rte_rwlock.h.

   staticintrte_rwlock_write_is_locked(rte_rwlock_t*rwl)[inline],[static]
       Test if the write lock is taken.

       Parametersrwl A pointer to a rwlock structure.

       Returns
           1 if the write lock is currently taken; 0 otherwise.

       Definition at line 256 of file rte_rwlock.h.

   staticvoidrte_rwlock_read_lock_tm(rte_rwlock_t*rwl)[inline],[static]
       Try to execute critical section in a hardware memory transaction, if it fails or  not  available  take  a
       read lock

       NOTE:  An  attempt  to  perform a HW I/O operation inside a hardware memory transaction always aborts the
       transaction since the CPU is not able to roll-back  should  the  transaction  fail.  Therefore,  hardware
       transactional locks are not advised to be used around rte_eth_rx_burst() and rte_eth_tx_burst() calls.

       Parametersrwl A pointer to a rwlock structure.

   staticvoidrte_rwlock_read_unlock_tm(rte_rwlock_t*rwl)[inline],[static]
       Commit hardware memory transaction or release the read lock if the lock is used as a fall-back

       Parametersrwl A pointer to the rwlock structure.

   staticvoidrte_rwlock_write_lock_tm(rte_rwlock_t*rwl)[inline],[static]
       Try  to  execute  critical  section in a hardware memory transaction, if it fails or not available take a
       write lock

       NOTE: An attempt to perform a HW I/O operation inside a hardware memory  transaction  always  aborts  the
       transaction  since  the  CPU  is  not  able to roll-back should the transaction fail. Therefore, hardware
       transactional locks are not advised to be used around rte_eth_rx_burst() and rte_eth_tx_burst() calls.

       Parametersrwl A pointer to a rwlock structure.

   staticvoidrte_rwlock_write_unlock_tm(rte_rwlock_t*rwl)[inline],[static]
       Commit hardware memory transaction or release the write lock if the lock is used as a fall-back

       Parametersrwl A pointer to a rwlock structure.

#defineRTE_RWLOCK_WAIT0x1/*Writeriswaiting*/
       The rte_rwlock_t type.

       Readers increment the counter by RTE_RWLOCK_READ (4) Writers set the RTE_RWLOCK_WRITE bit when lock is
       held and set the RTE_RWLOCK_WAIT bit while waiting.

       31 2 1 0 +-------------------+-+-+ | readers | | | +-------------------+-+-+ ^ ^ | | WRITE: lock held
       ----/ | WAIT: writer pending --/

       Definition at line 54 of file rte_rwlock.h.

   #defineRTE_RWLOCK_INITIALIZER{0}
       A static rwlock initializer.

       Definition at line 67 of file rte_rwlock.h.

       rte_rwlock.h

       #include <errno.h>
       #include <rte_branch_prediction.h>
       #include <rte_common.h>
       #include <rte_lock_annotations.h>
       #include <rte_pause.h>
       #include <rte_stdatomic.h>

   Macros
       #define RTE_RWLOCK_WAIT   0x1 /* Writer is waiting */
       #define RTE_RWLOCK_INITIALIZER   { 0 }

   Functions
       static void rte_rwlock_init (rte_rwlock_t *rwl)
       static void rte_rwlock_read_lock (rte_rwlock_t *rwl) __rte_no_thread_safety_analysis
       static int rte_rwlock_read_trylock (rte_rwlock_t *rwl) rwl) __rte_no_thread_safety_analysis
       static void rte_rwlock_read_unlock (rte_rwlock_t *rwl) __rte_no_thread_safety_analysis
       static int rte_rwlock_write_trylock (rte_rwlock_t *rwl) rwl) __rte_no_thread_safety_analysis
       static void rte_rwlock_write_lock (rte_rwlock_t *rwl) __rte_no_thread_safety_analysis
       static void rte_rwlock_write_unlock (rte_rwlock_t *rwl) __rte_no_thread_safety_analysis
       static int rte_rwlock_write_is_locked (rte_rwlock_t *rwl)
       static void rte_rwlock_read_lock_tm (rte_rwlock_t *rwl)
       static void rte_rwlock_read_unlock_tm (rte_rwlock_t *rwl)
       static void rte_rwlock_write_lock_tm (rte_rwlock_t *rwl)
       static void rte_rwlock_write_unlock_tm (rte_rwlock_t *rwl)