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Commit 13a55319 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge branch 'for-mingo' of... 

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

 into core/rcu

 - Updates to the handling of expedited grace periods, perhaps most
   notably parallelizing their initialization.  Other changes
   include fixes from Boqun Feng.

 - Miscellaneous fixes.  These include an nvme fix from Nitzan Carmi
   that I am carrying because it depends on a new SRCU function
   cleanup_srcu_struct_quiesced().  This branch also includes fixes
   from Byungchul Park and Yury Norov.

 - Updates to reduce lock contention in the rcu_node combining tree.
   These are in preparation for the consolidation of RCU-bh,
   RCU-preempt, and RCU-sched into a single flavor, which was
   requested by Linus Torvalds in response to a security flaw
   whose root cause included confusion between the multiple flavors
   of RCU.

 - Torture-test updates that save their users some time and effort.

Conflicts:
	drivers/nvme/host/core.c

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents 67b8d5c7 22df7316

Documentation/RCU/whatisRCU.txt

+2 −0
Original line number Diff line number Diff line 
What is RCU?  --  "Read, Copy, Update"



Please note that the "What is RCU?" LWN series is an excellent place

to start learning about RCU:

drivers/nvme/host/core.c

+1 −1
Original line number Diff line number Diff line
@@ -351,7 +351,7 @@ static void nvme_free_ns_head(struct kref *ref) 
	nvme_mpath_remove_disk(head);

	ida_simple_remove(&head->subsys->ns_ida, head->instance);

	list_del_init(&head->entry);

	cleanup_srcu_struct(&head->srcu);

	cleanup_srcu_struct_quiesced(&head->srcu);

	nvme_put_subsystem(head->subsys);

	kfree(head);

}

include/linux/rcupdate.h

+2 −2
Original line number Diff line number Diff line
@@ -188,13 +188,13 @@ static inline void exit_tasks_rcu_finish(void) { } 
#endif /* #else #ifdef CONFIG_TASKS_RCU */



/**

 * cond_resched_rcu_qs - Report potential quiescent states to RCU

 * cond_resched_tasks_rcu_qs - Report potential quiescent states to RCU

 *

 * This macro resembles cond_resched(), except that it is defined to

 * report potential quiescent states to RCU-tasks even if the cond_resched()

 * machinery were to be shut off, as some advocate for PREEMPT kernels.

 */

#define cond_resched_rcu_qs() \

#define cond_resched_tasks_rcu_qs() \

do { \

	if (!cond_resched()) \

		rcu_note_voluntary_context_switch_lite(current); \

include/linux/rcutree.h

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ static inline void synchronize_rcu_bh_expedited(void) 
void rcu_barrier(void);

void rcu_barrier_bh(void);

void rcu_barrier_sched(void);

bool rcu_eqs_special_set(int cpu);

unsigned long get_state_synchronize_rcu(void);

void cond_synchronize_rcu(unsigned long oldstate);

unsigned long get_state_synchronize_sched(void);

include/linux/sched.h

+0 −8
Original line number Diff line number Diff line
@@ -1653,7 +1653,6 @@ static inline int test_tsk_need_resched(struct task_struct *tsk) 
 * explicit rescheduling in places that are safe. The return

 * value indicates whether a reschedule was done in fact.

 * cond_resched_lock() will drop the spinlock before scheduling,

 * cond_resched_softirq() will enable bhs before scheduling.

 */

#ifndef CONFIG_PREEMPT

extern int _cond_resched(void);
@@ -1673,13 +1672,6 @@ extern int __cond_resched_lock(spinlock_t *lock); 
	__cond_resched_lock(lock);				\

})



extern int __cond_resched_softirq(void);



#define cond_resched_softirq() ({					\

	___might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET);	\

	__cond_resched_softirq();					\

})



static inline void cond_resched_rcu(void)

{

#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)