030c98aff1
Remove glib.h includes, as it is provided by osdep.h. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
145 lines
4.1 KiB
C
145 lines
4.1 KiB
C
#ifndef QEMU_RCU_H
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#define QEMU_RCU_H
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/*
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* urcu-mb.h
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*
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* Userspace RCU header with explicit memory barrier.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* IBM's contributions to this file may be relicensed under LGPLv2 or later.
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*/
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#include "qemu/thread.h"
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#include "qemu/queue.h"
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#include "qemu/atomic.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* Important !
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*
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* Each thread containing read-side critical sections must be registered
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* with rcu_register_thread() before calling rcu_read_lock().
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* rcu_unregister_thread() should be called before the thread exits.
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*/
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#ifdef DEBUG_RCU
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#define rcu_assert(args...) assert(args)
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#else
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#define rcu_assert(args...)
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#endif
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/*
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* Global quiescent period counter with low-order bits unused.
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* Using a int rather than a char to eliminate false register dependencies
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* causing stalls on some architectures.
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*/
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extern unsigned long rcu_gp_ctr;
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extern QemuEvent rcu_gp_event;
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struct rcu_reader_data {
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/* Data used by both reader and synchronize_rcu() */
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unsigned long ctr;
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bool waiting;
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/* Data used by reader only */
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unsigned depth;
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/* Data used for registry, protected by rcu_registry_lock */
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QLIST_ENTRY(rcu_reader_data) node;
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};
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extern __thread struct rcu_reader_data rcu_reader;
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static inline void rcu_read_lock(void)
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{
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struct rcu_reader_data *p_rcu_reader = &rcu_reader;
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unsigned ctr;
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if (p_rcu_reader->depth++ > 0) {
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return;
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}
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ctr = atomic_read(&rcu_gp_ctr);
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atomic_xchg(&p_rcu_reader->ctr, ctr);
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}
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static inline void rcu_read_unlock(void)
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{
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struct rcu_reader_data *p_rcu_reader = &rcu_reader;
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assert(p_rcu_reader->depth != 0);
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if (--p_rcu_reader->depth > 0) {
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return;
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}
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atomic_xchg(&p_rcu_reader->ctr, 0);
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if (unlikely(atomic_read(&p_rcu_reader->waiting))) {
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atomic_set(&p_rcu_reader->waiting, false);
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qemu_event_set(&rcu_gp_event);
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}
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}
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extern void synchronize_rcu(void);
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/*
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* Reader thread registration.
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*/
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extern void rcu_register_thread(void);
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extern void rcu_unregister_thread(void);
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extern void rcu_after_fork(void);
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struct rcu_head;
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typedef void RCUCBFunc(struct rcu_head *head);
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struct rcu_head {
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struct rcu_head *next;
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RCUCBFunc *func;
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};
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extern void call_rcu1(struct rcu_head *head, RCUCBFunc *func);
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/* The operands of the minus operator must have the same type,
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* which must be the one that we specify in the cast.
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*/
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#define call_rcu(head, func, field) \
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call_rcu1(({ \
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char __attribute__((unused)) \
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offset_must_be_zero[-offsetof(typeof(*(head)), field)], \
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func_type_invalid = (func) - (void (*)(typeof(head)))(func); \
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&(head)->field; \
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}), \
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(RCUCBFunc *)(func))
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#define g_free_rcu(obj, field) \
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call_rcu1(({ \
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char __attribute__((unused)) \
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offset_must_be_zero[-offsetof(typeof(*(obj)), field)]; \
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&(obj)->field; \
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}), \
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(RCUCBFunc *)g_free);
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#ifdef __cplusplus
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}
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#endif
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#endif /* QEMU_RCU_H */
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