diff options
Diffstat (limited to 'include/linux/srcutiny.h')
| -rw-r--r-- | include/linux/srcutiny.h | 94 |
1 files changed, 69 insertions, 25 deletions
diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h index b19216aaaef2..e0698024667a 100644 --- a/include/linux/srcutiny.h +++ b/include/linux/srcutiny.h @@ -1,24 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ /* * Sleepable Read-Copy Update mechanism for mutual exclusion, * tiny variant. * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, you can access it online at - * http://www.gnu.org/licenses/gpl-2.0.html. - * * Copyright (C) IBM Corporation, 2017 * - * Author: Paul McKenney <paulmck@us.ibm.com> + * Author: Paul McKenney <paulmck@linux.ibm.com> */ #ifndef _LINUX_SRCU_TINY_H @@ -28,9 +15,10 @@ struct srcu_struct { short srcu_lock_nesting[2]; /* srcu_read_lock() nesting depth. */ - short srcu_idx; /* Current reader array element. */ u8 srcu_gp_running; /* GP workqueue running? */ u8 srcu_gp_waiting; /* GP waiting for readers? */ + unsigned long srcu_idx; /* Current reader array element in bit 0x2. */ + unsigned long srcu_idx_max; /* Furthest future srcu_idx request. */ struct swait_queue_head srcu_wq; /* Last srcu_read_unlock() wakes GP. */ struct rcu_head *srcu_cb_head; /* Pending callbacks: Head. */ @@ -43,7 +31,7 @@ struct srcu_struct { void srcu_drive_gp(struct work_struct *wp); -#define __SRCU_STRUCT_INIT(name, __ignored) \ +#define __SRCU_STRUCT_INIT(name, __ignored, ___ignored, ____ignored) \ { \ .srcu_wq = __SWAIT_QUEUE_HEAD_INITIALIZER(name.srcu_wq), \ .srcu_cb_tail = &name.srcu_cb_head, \ @@ -56,9 +44,25 @@ void srcu_drive_gp(struct work_struct *wp); * Tree SRCU, which needs some per-CPU data. */ #define DEFINE_SRCU(name) \ - struct srcu_struct name = __SRCU_STRUCT_INIT(name, name) + struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name, name) #define DEFINE_STATIC_SRCU(name) \ - static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name) + static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name, name) +#define DEFINE_SRCU_FAST(name) DEFINE_SRCU(name) +#define DEFINE_STATIC_SRCU_FAST(name) \ + static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name, name) +#define DEFINE_SRCU_FAST_UPDOWN(name) DEFINE_SRCU(name) +#define DEFINE_STATIC_SRCU_FAST_UPDOWN(name) \ + static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name, name, name) + +// Dummy structure for srcu_notifier_head. +struct srcu_usage { }; +#define __SRCU_USAGE_INIT(name) { } +#define __init_srcu_struct_fast __init_srcu_struct +#define __init_srcu_struct_fast_updown __init_srcu_struct +#ifndef CONFIG_DEBUG_LOCK_ALLOC +#define init_srcu_struct_fast init_srcu_struct +#define init_srcu_struct_fast_updown init_srcu_struct +#endif // #ifndef CONFIG_DEBUG_LOCK_ALLOC void synchronize_srcu(struct srcu_struct *ssp); @@ -72,11 +76,46 @@ static inline int __srcu_read_lock(struct srcu_struct *ssp) { int idx; - idx = READ_ONCE(ssp->srcu_idx); - WRITE_ONCE(ssp->srcu_lock_nesting[idx], ssp->srcu_lock_nesting[idx] + 1); + preempt_disable(); // Needed for PREEMPT_LAZY + idx = ((READ_ONCE(ssp->srcu_idx) + 1) & 0x2) >> 1; + WRITE_ONCE(ssp->srcu_lock_nesting[idx], READ_ONCE(ssp->srcu_lock_nesting[idx]) + 1); + preempt_enable(); return idx; } +struct srcu_ctr; + +static inline bool __srcu_ptr_to_ctr(struct srcu_struct *ssp, struct srcu_ctr __percpu *scpp) +{ + return (int)(intptr_t)(struct srcu_ctr __force __kernel *)scpp; +} + +static inline struct srcu_ctr __percpu *__srcu_ctr_to_ptr(struct srcu_struct *ssp, int idx) +{ + return (struct srcu_ctr __percpu *)(intptr_t)idx; +} + +static inline struct srcu_ctr __percpu *__srcu_read_lock_fast(struct srcu_struct *ssp) +{ + return __srcu_ctr_to_ptr(ssp, __srcu_read_lock(ssp)); +} + +static inline void __srcu_read_unlock_fast(struct srcu_struct *ssp, struct srcu_ctr __percpu *scp) +{ + __srcu_read_unlock(ssp, __srcu_ptr_to_ctr(ssp, scp)); +} + +static inline struct srcu_ctr __percpu *__srcu_read_lock_fast_updown(struct srcu_struct *ssp) +{ + return __srcu_ctr_to_ptr(ssp, __srcu_read_lock(ssp)); +} + +static inline +void __srcu_read_unlock_fast_updown(struct srcu_struct *ssp, struct srcu_ctr __percpu *scp) +{ + __srcu_read_unlock(ssp, __srcu_ptr_to_ctr(ssp, scp)); +} + static inline void synchronize_srcu_expedited(struct srcu_struct *ssp) { synchronize_srcu(ssp); @@ -87,17 +126,22 @@ static inline void srcu_barrier(struct srcu_struct *ssp) synchronize_srcu(ssp); } +static inline void srcu_expedite_current(struct srcu_struct *ssp) { } +#define srcu_check_read_flavor(ssp, read_flavor) do { } while (0) + /* Defined here to avoid size increase for non-torture kernels. */ static inline void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf) { int idx; - idx = READ_ONCE(ssp->srcu_idx) & 0x1; - pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n", + idx = ((data_race(READ_ONCE(ssp->srcu_idx)) + 1) & 0x2) >> 1; + pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd) gp: %lu->%lu\n", tt, tf, idx, - READ_ONCE(ssp->srcu_lock_nesting[!idx]), - READ_ONCE(ssp->srcu_lock_nesting[idx])); + data_race(READ_ONCE(ssp->srcu_lock_nesting[!idx])), + data_race(READ_ONCE(ssp->srcu_lock_nesting[idx])), + data_race(READ_ONCE(ssp->srcu_idx)), + data_race(READ_ONCE(ssp->srcu_idx_max))); } #endif |