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Commit e85a4710 authored by Alexander Graf's avatar Alexander Graf Committed by Benjamin Herrenschmidt
Browse files

Split init_new_context and destroy_context 



For KVM we need to allocate a new context id, but don't really care about
all the mm context around it.

So let's split the alloc and destroy functions for the context id, so we can
grab one without allocating an mm context.

Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 4ab79aa8

arch/powerpc/include/asm/mmu_context.h

+2 −0
Original line number Diff line number Diff line
@@ -23,6 +23,8 @@ extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm); 
extern void set_context(unsigned long id, pgd_t *pgd);



#ifdef CONFIG_PPC_BOOK3S_64

extern int __init_new_context(void);

extern void __destroy_context(int context_id);

static inline void mmu_context_init(void) { }

#else

extern void mmu_context_init(void);

arch/powerpc/mm/mmu_context_hash64.c

+21 −3
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/mm.h>

#include <linux/spinlock.h>

#include <linux/idr.h>

#include <linux/module.h>



#include <asm/mmu_context.h>
@@ -32,7 +33,7 @@ static DEFINE_IDR(mmu_context_idr); 
#define NO_CONTEXT	0

#define MAX_CONTEXT	((1UL << 19) - 1)



int init_new_context(struct task_struct *tsk, struct mm_struct *mm)

int __init_new_context(void)

{

	int index;

	int err;
@@ -57,6 +58,18 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm) 
		return -ENOMEM;

	}



	return index;

}

EXPORT_SYMBOL_GPL(__init_new_context);



int init_new_context(struct task_struct *tsk, struct mm_struct *mm)

{

	int index;



	index = __init_new_context();

	if (index < 0)

		return index;



	/* The old code would re-promote on fork, we don't do that

	 * when using slices as it could cause problem promoting slices

	 * that have been forced down to 4K
@@ -68,11 +81,16 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm) 
	return 0;

}



void destroy_context(struct mm_struct *mm)

void __destroy_context(int context_id)

{

	spin_lock(&mmu_context_lock);

	idr_remove(&mmu_context_idr, mm->context.id);

	idr_remove(&mmu_context_idr, context_id);

	spin_unlock(&mmu_context_lock);

}

EXPORT_SYMBOL_GPL(__destroy_context);



void destroy_context(struct mm_struct *mm)

{

	__destroy_context(mm->context.id);

	mm->context.id = NO_CONTEXT;

}