75 lines
1.7 KiB
C
75 lines
1.7 KiB
C
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/*
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* Copyright 2013 Red Hat Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Authors: Jérôme Glisse <jglisse@redhat.com>
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*/
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/*
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* Refer to include/linux/hmm.h for information about heterogeneous memory
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* management or HMM for short.
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*/
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#include <linux/mm.h>
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#include <linux/hmm.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#ifdef CONFIG_HMM
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/*
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* struct hmm - HMM per mm struct
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*
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* @mm: mm struct this HMM struct is bound to
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*/
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struct hmm {
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struct mm_struct *mm;
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};
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/*
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* hmm_register - register HMM against an mm (HMM internal)
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*
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* @mm: mm struct to attach to
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*
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* This is not intended to be used directly by device drivers. It allocates an
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* HMM struct if mm does not have one, and initializes it.
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*/
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static struct hmm *hmm_register(struct mm_struct *mm)
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{
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if (!mm->hmm) {
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struct hmm *hmm = NULL;
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hmm = kmalloc(sizeof(*hmm), GFP_KERNEL);
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if (!hmm)
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return NULL;
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hmm->mm = mm;
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spin_lock(&mm->page_table_lock);
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if (!mm->hmm)
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mm->hmm = hmm;
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else
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kfree(hmm);
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spin_unlock(&mm->page_table_lock);
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}
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/*
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* The hmm struct can only be freed once the mm_struct goes away,
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* hence we should always have pre-allocated an new hmm struct
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* above.
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*/
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return mm->hmm;
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}
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void hmm_mm_destroy(struct mm_struct *mm)
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{
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kfree(mm->hmm);
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}
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#endif /* CONFIG_HMM */
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