fom_long_lock.h

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/* -*- C -*- */
/*
 * Copyright (c) 2012-2020 Seagate Technology LLC and/or its Affiliates
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For any questions about this software or licensing,
 * please email opensource@seagate.com or cortx-questions@seagate.com.
 *
 */


#pragma once

#ifndef __MOTR_LONG_LOCK_H__
#define __MOTR_LONG_LOCK_H__

#include "fop/fop.h"
#include "lib/list.h"
#include "lib/chan.h"
#include "lib/mutex.h"
#include "lib/bob.h"

enum m0_long_lock_state {
        M0_LONG_LOCK_UNLOCKED,
        M0_LONG_LOCK_RD_LOCKED,
        M0_LONG_LOCK_WR_LOCKED
};

enum m0_long_lock_type {
        M0_LONG_LOCK_READER,
        M0_LONG_LOCK_WRITER
};

struct m0_long_lock_addb2 {
        m0_time_t la_taken;
        bool      la_waiting;
        m0_time_t la_wait;
};

struct m0_long_lock_link {
        struct m0_fom             *lll_fom;
        struct m0_tlink            lll_lock_linkage;
        uint64_t                   lll_magix;
        enum m0_long_lock_type     lll_lock_type;
        struct m0_long_lock_addb2 *lll_addb2;
};

struct m0_long_lock {
        struct m0_tl            l_owners;
        struct m0_tl            l_waiters;
        struct m0_mutex         l_lock;
        enum m0_long_lock_state l_state;
        uint64_t                l_magix;
};

//#ifdef __KERNEL__
#if 1 /* XXX */
#define M0_BE_LONG_LOCK_PAD (264 + 88)
#else
#define M0_BE_LONG_LOCK_PAD (136 + 40)
#endif

struct m0_be_long_lock {
        union {
                struct m0_long_lock llock;
                char                pad[M0_BE_LONG_LOCK_PAD];
        } bll_u;
} M0_XCA_BLOB M0_XCA_DOMAIN(be);
M0_BASSERT(sizeof(struct m0_long_lock) <=
           sizeof(M0_FIELD_VALUE(struct m0_be_long_lock, bll_u.pad)));

#define M0_FOM_LONG_LOCK_RETURN(rc) ((rc) ? M0_FSO_AGAIN : M0_FSO_WAIT)

M0_INTERNAL void m0_long_lock_init(struct m0_long_lock *lock);

M0_INTERNAL void m0_long_lock_fini(struct m0_long_lock *lock);

M0_INTERNAL bool m0_long_read_lock(struct m0_long_lock *lock,
                                   struct m0_long_lock_link *link,
                                   int next_phase);

M0_INTERNAL bool m0_long_write_lock(struct m0_long_lock *lock,
                                    struct m0_long_lock_link *link,
                                    int next_phase);

M0_INTERNAL bool m0_long_lock(struct m0_long_lock *lock, bool write,
                              struct m0_long_lock_link *link,
                              int next_phase);

M0_INTERNAL void m0_long_read_unlock(struct m0_long_lock *lock,
                                     struct m0_long_lock_link *link);

M0_INTERNAL void m0_long_write_unlock(struct m0_long_lock *lock,
                                      struct m0_long_lock_link *link);

M0_INTERNAL void m0_long_unlock(struct m0_long_lock *lock,
                                struct m0_long_lock_link *link);

M0_INTERNAL bool m0_long_is_read_locked(struct m0_long_lock *lock,
                                        const struct m0_fom *fom);

M0_INTERNAL bool m0_long_is_write_locked(struct m0_long_lock *lock,
                                         const struct m0_fom *fom);

M0_INTERNAL void m0_long_lock_link_init(struct m0_long_lock_link *link,
                                        struct m0_fom *fom,
                                        struct m0_long_lock_addb2 *addb2);

M0_INTERNAL void m0_long_lock_link_fini(struct m0_long_lock_link *link);

M0_BOB_DECLARE(M0_EXTERN, m0_long_lock);
M0_BOB_DECLARE(M0_EXTERN, m0_long_lock_link);

M0_INTERNAL void m0_fom_ll_global_init(void);


#endif /* __MOTR_LONG_LOCK_H__ */

/*
 *  Local variables:
 *  c-indentation-style: "K&R"
 *  c-basic-offset: 8
 *  tab-width: 8
 *  fill-column: 80
 *  scroll-step: 1
 *  End:
 */