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https://github.com/linux-msm/laptops-kernel.git
synced 2026-08-13 14:19:53 -07:00
Puranjay MohanandPaul E. McKenney
736084507f
The polled grace-period state structure rcu_gp_oldstate holds a snapshot of the normal (and, on SMP, expedited) grace-period sequence numbers. Upcoming changes store this structure in the callback segment list, where the "oldstate" name reads poorly: there it represents the grace period a segment is waiting on and is also compared against the current grace-period state. Rename struct rcu_gp_oldstate to the more neutral struct rcu_gp_seq, and shorten its members rgos_norm and rgos_exp to norm and exp. Local variables and parameters of this type are renamed from rgosp/rgos to gsp/gs accordingly. While at it, provide a single definition of the structure in rcupdate.h rather than separate Tiny-RCU and Tree-RCU definitions, and give it the ->exp field unconditionally. Tiny RCU does not track expedited grace periods and leaves ->exp unused, but a single definition that always has ->exp lets the shared callback code in rcu_segcblist.c reference it without CONFIG_SMP guards, including on !SMP builds. No functional change. Signed-off-by: Puranjay Mohan <puranjay@kernel.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
141 lines
3.6 KiB
C
141 lines
3.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
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*
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* Copyright IBM Corporation, 2008
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*
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* Author: Paul E. McKenney <paulmck@linux.ibm.com>
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*
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* For detailed explanation of Read-Copy Update mechanism see -
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* Documentation/RCU
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*/
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#ifndef __LINUX_TINY_H
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#define __LINUX_TINY_H
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#include <asm/param.h> /* for HZ */
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// Maximum number of rcu_gp_seq values corresponding to
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// not-yet-completed RCU grace periods.
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#define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 2
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/*
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* Are the two oldstate values the same? See the Tree RCU version for
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* docbook header.
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*/
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static inline bool same_state_synchronize_rcu_full(struct rcu_gp_seq *rgosp1,
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struct rcu_gp_seq *rgosp2)
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{
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return rgosp1->norm == rgosp2->norm;
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}
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unsigned long get_state_synchronize_rcu(void);
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static inline void get_state_synchronize_rcu_full(struct rcu_gp_seq *gsp)
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{
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gsp->norm = get_state_synchronize_rcu();
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}
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unsigned long start_poll_synchronize_rcu(void);
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static inline void start_poll_synchronize_rcu_full(struct rcu_gp_seq *gsp)
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{
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gsp->norm = start_poll_synchronize_rcu();
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}
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bool poll_state_synchronize_rcu(unsigned long oldstate);
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static inline bool poll_state_synchronize_rcu_full(struct rcu_gp_seq *gsp)
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{
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return poll_state_synchronize_rcu(gsp->norm);
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}
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static inline void cond_synchronize_rcu(unsigned long oldstate)
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{
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might_sleep();
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}
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static inline void cond_synchronize_rcu_full(struct rcu_gp_seq *gsp)
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{
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cond_synchronize_rcu(gsp->norm);
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}
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static inline unsigned long start_poll_synchronize_rcu_expedited(void)
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{
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return start_poll_synchronize_rcu();
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}
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static inline void start_poll_synchronize_rcu_expedited_full(struct rcu_gp_seq *gsp)
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{
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gsp->norm = start_poll_synchronize_rcu_expedited();
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}
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static inline void cond_synchronize_rcu_expedited(unsigned long oldstate)
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{
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cond_synchronize_rcu(oldstate);
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}
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static inline void cond_synchronize_rcu_expedited_full(struct rcu_gp_seq *gsp)
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{
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cond_synchronize_rcu_expedited(gsp->norm);
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}
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extern void rcu_barrier(void);
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static inline void synchronize_rcu_expedited(void)
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{
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synchronize_rcu();
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}
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void rcu_qs(void);
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static inline void rcu_softirq_qs(void)
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{
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rcu_qs();
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}
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#define rcu_note_context_switch(preempt) \
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do { \
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rcu_qs(); \
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rcu_tasks_qs(current, (preempt)); \
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} while (0)
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static inline int rcu_needs_cpu(void)
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{
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return 0;
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}
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static inline void rcu_request_urgent_qs_task(struct task_struct *t) { }
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/*
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* Take advantage of the fact that there is only one CPU, which
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* allows us to ignore virtualization-based context switches.
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*/
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static inline void rcu_virt_note_context_switch(void) { }
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static inline void rcu_cpu_stall_reset(void) { }
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static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; }
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static inline void rcu_irq_exit_check_preempt(void) { }
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static inline void exit_rcu(void) { }
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static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t)
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{
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return false;
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}
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static inline void rcu_preempt_deferred_qs(struct task_struct *t) { }
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void rcu_scheduler_starting(void);
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static inline void rcu_end_inkernel_boot(void) { }
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static inline bool rcu_inkernel_boot_has_ended(void) { return true; }
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static inline bool rcu_is_watching(void) { return true; }
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static inline void rcu_momentary_eqs(void) { }
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/* Avoid RCU read-side critical sections leaking across. */
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static inline void rcu_all_qs(void) { barrier(); }
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/* RCUtree hotplug events */
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#define rcutree_prepare_cpu NULL
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#define rcutree_online_cpu NULL
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#define rcutree_offline_cpu NULL
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#define rcutree_dead_cpu NULL
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#define rcutree_dying_cpu NULL
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static inline void rcutree_report_cpu_starting(unsigned int cpu) { }
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#endif /* __LINUX_RCUTINY_H */
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