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87 lines
1.7 KiB
C
87 lines
1.7 KiB
C
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/*
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* Copyright 2014 IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/rcupdate.h>
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#include <asm/errno.h>
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#include <misc/cxl.h>
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#include "cxl.h"
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/* protected by rcu */
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static struct cxl_calls *cxl_calls;
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atomic_t cxl_use_count = ATOMIC_INIT(0);
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EXPORT_SYMBOL(cxl_use_count);
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#ifdef CONFIG_CXL_MODULE
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static inline struct cxl_calls *cxl_calls_get(void)
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{
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struct cxl_calls *calls = NULL;
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rcu_read_lock();
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calls = rcu_dereference(cxl_calls);
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if (calls && !try_module_get(calls->owner))
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calls = NULL;
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rcu_read_unlock();
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return calls;
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}
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static inline void cxl_calls_put(struct cxl_calls *calls)
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{
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BUG_ON(calls != cxl_calls);
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/* we don't need to rcu this, as we hold a reference to the module */
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module_put(cxl_calls->owner);
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}
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#else /* !defined CONFIG_CXL_MODULE */
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static inline struct cxl_calls *cxl_calls_get(void)
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{
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return cxl_calls;
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}
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static inline void cxl_calls_put(struct cxl_calls *calls) { }
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#endif /* CONFIG_CXL_MODULE */
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void cxl_slbia(struct mm_struct *mm)
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{
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struct cxl_calls *calls;
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calls = cxl_calls_get();
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if (!calls)
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return;
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if (cxl_ctx_in_use())
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calls->cxl_slbia(mm);
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cxl_calls_put(calls);
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}
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int register_cxl_calls(struct cxl_calls *calls)
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{
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if (cxl_calls)
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return -EBUSY;
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rcu_assign_pointer(cxl_calls, calls);
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return 0;
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}
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EXPORT_SYMBOL_GPL(register_cxl_calls);
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void unregister_cxl_calls(struct cxl_calls *calls)
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{
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BUG_ON(cxl_calls->owner != calls->owner);
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RCU_INIT_POINTER(cxl_calls, NULL);
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synchronize_rcu();
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}
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EXPORT_SYMBOL_GPL(unregister_cxl_calls);
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