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Revision e700898fa075c69b3ae02b702ab57fb75e1a82ec authored by Mike Kravetz on 12 December 2022, 23:50:41 UTC, committed by Andrew Morton on 21 December 2022, 22:31:52 UTC 
hugetlb: really allocate vma lock for all sharable vmas
 
Commit bbff39cc6cbc ("hugetlb: allocate vma lock for all sharable vmas")
removed the pmd sharable checks in the vma lock helper routines.  However,
it left the functional version of helper routines behind #ifdef
CONFIG_ARCH_WANT_HUGE_PMD_SHARE.  Therefore, the vma lock is not being
used for sharable vmas on architectures that do not support pmd sharing. 
On these architectures, a potential fault/truncation race is exposed that
could leave pages in a hugetlb file past i_size until the file is removed.

Move the functional vma lock helpers outside the ifdef, and remove the
non-functional stubs.  Since the vma lock is not just for pmd sharing,
rename the routine __vma_shareable_flags_pmd.

Link: https://lkml.kernel.org/r/20221212235042.178355-1-mike.kravetz@oracle.com
Fixes: bbff39cc6cbc ("hugetlb: allocate vma lock for all sharable vmas")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
1 parent 7ba594d
Raw File
page_reporting.h 
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _MM_PAGE_REPORTING_H
#define _MM_PAGE_REPORTING_H

#include <linux/mmzone.h>
#include <linux/pageblock-flags.h>
#include <linux/page-isolation.h>
#include <linux/jump_label.h>
#include <linux/slab.h>
#include <linux/pgtable.h>
#include <linux/scatterlist.h>

#ifdef CONFIG_PAGE_REPORTING
DECLARE_STATIC_KEY_FALSE(page_reporting_enabled);
extern unsigned int page_reporting_order;
void __page_reporting_notify(void);

static inline bool page_reported(struct page *page)
{
	return static_branch_unlikely(&page_reporting_enabled) &&
	       PageReported(page);
}

/**
 * page_reporting_notify_free - Free page notification to start page processing
 *
 * This function is meant to act as a screener for __page_reporting_notify
 * which will determine if a give zone has crossed over the high-water mark
 * that will justify us beginning page treatment. If we have crossed that
 * threshold then it will start the process of pulling some pages and
 * placing them in the batch list for treatment.
 */
static inline void page_reporting_notify_free(unsigned int order)
{
	/* Called from hot path in __free_one_page() */
	if (!static_branch_unlikely(&page_reporting_enabled))
		return;

	/* Determine if we have crossed reporting threshold */
	if (order < page_reporting_order)
		return;

	/* This will add a few cycles, but should be called infrequently */
	__page_reporting_notify();
}
#else /* CONFIG_PAGE_REPORTING */
#define page_reported(_page)	false

static inline void page_reporting_notify_free(unsigned int order)
{
}
#endif /* CONFIG_PAGE_REPORTING */
#endif /*_MM_PAGE_REPORTING_H */
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