The branch stable/13 has been updated by wulf: URL: https://cgit.FreeBSD.org/src/commit/?id=801a4bcab69f15a40a86c330aa12986f43287967
commit 801a4bcab69f15a40a86c330aa12986f43287967 Author: Vladimir Kondratyev <[email protected]> AuthorDate: 2021-07-05 00:20:55 +0000 Commit: Vladimir Kondratyev <[email protected]> CommitDate: 2021-07-20 22:43:52 +0000 LinuxKPI: Implement sequence counters and sequential locks as a thin wrapper around native version found in sys/seqc.h. This replaces out-of-base GPLv2-licensed code used by drm-kmod. Reviewed by: hselasky Differential revision: https://reviews.freebsd.org/D31006 (cherry picked from commit 8b33cb8303d3d7ff12e34327a872ef9fdb29eab9) --- sys/compat/linuxkpi/common/include/linux/seqlock.h | 137 +++++++++++++++++++++ 1 file changed, 137 insertions(+) diff --git a/sys/compat/linuxkpi/common/include/linux/seqlock.h b/sys/compat/linuxkpi/common/include/linux/seqlock.h new file mode 100644 index 000000000000..b7ae6e32ae69 --- /dev/null +++ b/sys/compat/linuxkpi/common/include/linux/seqlock.h @@ -0,0 +1,137 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2021 Vladimir Kondratyev <[email protected]> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. 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. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. + */ + +#ifndef _LINUX_SEQLOCK_H__ +#define _LINUX_SEQLOCK_H__ + +#include <sys/param.h> +#include <sys/lock.h> +#include <sys/mutex.h> +#include <sys/seqc.h> + +struct lock_class_key; + +struct seqcount { + seqc_t seqc; +}; +typedef struct seqcount seqcount_t; + +struct seqlock { + struct mtx seql_lock; + struct seqcount seql_count; +}; +typedef struct seqlock seqlock_t; + +static inline void +__seqcount_init(struct seqcount *seqcount, const char *name __unused, + struct lock_class_key *key __unused) +{ + seqcount->seqc = 0; +} +#define seqcount_init(seqcount) __seqcount_init(seqcount, NULL, NULL) + +static inline void +write_seqcount_begin(struct seqcount *seqcount) +{ + seqc_sleepable_write_begin(&seqcount->seqc); +} + +static inline void +write_seqcount_end(struct seqcount *seqcount) +{ + seqc_sleepable_write_end(&seqcount->seqc); +} + +/* + * XXX: Are predicts from inline functions still not honored by clang? + */ +#define __read_seqcount_retry(seqcount, gen) \ + (!seqc_consistent_nomb(&(seqcount)->seqc, gen)) +#define read_seqcount_retry(seqcount, gen) \ + (!seqc_consistent(&(seqcount)->seqc, gen)) + +static inline unsigned +read_seqcount_begin(const struct seqcount *seqcount) +{ + return (seqc_read(&seqcount->seqc)); +} + +static inline unsigned +raw_read_seqcount(const struct seqcount *seqcount) +{ + return (seqc_read_any(&seqcount->seqc)); +} + +static inline void +seqlock_init(struct seqlock *seqlock) +{ + /* + * Don't enroll to witness(4) to avoid orphaned references after struct + * seqlock has been freed. There is no seqlock destructor exists so we + * can't expect automatic mtx_destroy() execution before free(). + */ + mtx_init(&seqlock->seql_lock, "seqlock", NULL, MTX_DEF|MTX_NOWITNESS); + seqcount_init(&seqlock->seql_count); +} + +static inline void +write_seqlock(struct seqlock *seqlock) +{ + mtx_lock(&seqlock->seql_lock); + write_seqcount_begin(&seqlock->seql_count); +} + +static inline void +write_sequnlock(struct seqlock *seqlock) +{ + write_seqcount_end(&seqlock->seql_count); + mtx_unlock(&seqlock->seql_lock); +} + +#define write_seqlock_irqsave(seqlock, flags) do { \ + (flags) = 0; \ + write_seqlock(seqlock); \ +} while (0) + +static inline void +write_sequnlock_irqrestore(struct seqlock *seqlock, + unsigned long flags __unused) +{ + write_sequnlock(seqlock); +} + +static inline unsigned +read_seqbegin(const struct seqlock *seqlock) +{ + return (read_seqcount_begin(&seqlock->seql_count)); +} + +#define read_seqretry(seqlock, gen) \ + read_seqcount_retry(&(seqlock)->seql_count, gen) + +#endif /* _LINUX_SEQLOCK_H__ */ _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all To unsubscribe, send any mail to "[email protected]"
