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/*
* Copyright 2014 IBM Corp.
*
* 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.
*/
#include <linux/module.h>
#include <linux/rcupdate.h>
#include <asm/errno.h>
#include <misc/cxl.h>
#include "cxl.h"
/* protected by rcu */
static struct cxl_calls *cxl_calls;
atomic_t cxl_use_count = ATOMIC_INIT(0);
EXPORT_SYMBOL(cxl_use_count);
#ifdef CONFIG_CXL_MODULE
static inline struct cxl_calls *cxl_calls_get(void)
{
struct cxl_calls *calls = NULL;
rcu_read_lock();
calls = rcu_dereference(cxl_calls);
if (calls && !try_module_get(calls->owner))
calls = NULL;
rcu_read_unlock();
return calls;
}
static inline void cxl_calls_put(struct cxl_calls *calls)
{
BUG_ON(calls != cxl_calls);
/* we don't need to rcu this, as we hold a reference to the module */
module_put(cxl_calls->owner);
}
#else /* !defined CONFIG_CXL_MODULE */
static inline struct cxl_calls *cxl_calls_get(void)
{
return cxl_calls;
}
static inline void cxl_calls_put(struct cxl_calls *calls) { }
#endif /* CONFIG_CXL_MODULE */
void cxl_slbia(struct mm_struct *mm)
{
struct cxl_calls *calls;
calls = cxl_calls_get();
if (!calls)
return;
if (cxl_ctx_in_use())
calls->cxl_slbia(mm);
cxl_calls_put(calls);
}
int register_cxl_calls(struct cxl_calls *calls)
{
if (cxl_calls)
return -EBUSY;
rcu_assign_pointer(cxl_calls, calls);
return 0;
}
EXPORT_SYMBOL_GPL(register_cxl_calls);
void unregister_cxl_calls(struct cxl_calls *calls)
{
BUG_ON(cxl_calls->owner != calls->owner);
RCU_INIT_POINTER(cxl_calls, NULL);
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(unregister_cxl_calls);
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