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Commit 8affb067 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge branch 'rcu/urgent' of... 

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

 into rcu/urgent

Pull RCU fix from Paul E. McKenney:

" This series enables srcu_read_lock() and srcu_read_unlock() to be used from
  interrupt handlers, which fixes a bug in KVM's use of SRCU in delivery
  of interrupts to guest OSes. "

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents b29794ec 1123a604

include/linux/srcu.h

+0 −2
Original line number Diff line number Diff line
@@ -172,9 +172,7 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp) 
{

	int retval;



	preempt_disable();

	retval = __srcu_read_lock(sp);

	preempt_enable();

	rcu_lock_acquire(&(sp)->dep_map);

	return retval;

}

kernel/rcu/srcu.c

+2 −3
Original line number Diff line number Diff line
@@ -263,7 +263,7 @@ EXPORT_SYMBOL_GPL(cleanup_srcu_struct); 


/*

 * Counts the new reader in the appropriate per-CPU element of the

 * srcu_struct.  Must be called from process context.

 * srcu_struct.

 * Returns an index that must be passed to the matching srcu_read_unlock().

 */

int __srcu_read_lock(struct srcu_struct *sp)
@@ -271,7 +271,7 @@ int __srcu_read_lock(struct srcu_struct *sp) 
	int idx;



	idx = READ_ONCE(sp->completed) & 0x1;

	__this_cpu_inc(sp->per_cpu_ref->lock_count[idx]);

	this_cpu_inc(sp->per_cpu_ref->lock_count[idx]);

	smp_mb(); /* B */  /* Avoid leaking the critical section. */

	return idx;

}
@@ -281,7 +281,6 @@ EXPORT_SYMBOL_GPL(__srcu_read_lock); 
 * Removes the count for the old reader from the appropriate per-CPU

 * element of the srcu_struct.  Note that this may well be a different

 * CPU than that which was incremented by the corresponding srcu_read_lock().

 * Must be called from process context.

 */

void __srcu_read_unlock(struct srcu_struct *sp, int idx)

{

kernel/rcu/srcutiny.c

+4 −3
Original line number Diff line number Diff line
@@ -97,8 +97,9 @@ EXPORT_SYMBOL_GPL(cleanup_srcu_struct); 


/*

 * Counts the new reader in the appropriate per-CPU element of the

 * srcu_struct.  Must be called from process context.

 * Returns an index that must be passed to the matching srcu_read_unlock().

 * srcu_struct.  Can be invoked from irq/bh handlers, but the matching

 * __srcu_read_unlock() must be in the same handler instance.  Returns an

 * index that must be passed to the matching srcu_read_unlock().

 */

int __srcu_read_lock(struct srcu_struct *sp)

{
@@ -112,7 +113,7 @@ EXPORT_SYMBOL_GPL(__srcu_read_lock); 


/*

 * Removes the count for the old reader from the appropriate element of

 * the srcu_struct.  Must be called from process context.

 * the srcu_struct.

 */

void __srcu_read_unlock(struct srcu_struct *sp, int idx)

{

kernel/rcu/srcutree.c

+2 −3
Original line number Diff line number Diff line
@@ -357,7 +357,7 @@ EXPORT_SYMBOL_GPL(cleanup_srcu_struct); 


/*

 * Counts the new reader in the appropriate per-CPU element of the

 * srcu_struct.  Must be called from process context.

 * srcu_struct.

 * Returns an index that must be passed to the matching srcu_read_unlock().

 */

int __srcu_read_lock(struct srcu_struct *sp)
@@ -365,7 +365,7 @@ int __srcu_read_lock(struct srcu_struct *sp) 
	int idx;



	idx = READ_ONCE(sp->srcu_idx) & 0x1;

	__this_cpu_inc(sp->sda->srcu_lock_count[idx]);

	this_cpu_inc(sp->sda->srcu_lock_count[idx]);

	smp_mb(); /* B */  /* Avoid leaking the critical section. */

	return idx;

}
@@ -375,7 +375,6 @@ EXPORT_SYMBOL_GPL(__srcu_read_lock); 
 * Removes the count for the old reader from the appropriate per-CPU

 * element of the srcu_struct.  Note that this may well be a different

 * CPU than that which was incremented by the corresponding srcu_read_lock().

 * Must be called from process context.

 */

void __srcu_read_unlock(struct srcu_struct *sp, int idx)

{