Commit 45199f71 authored by Dev Jain's avatar Dev Jain Committed by Andrew Morton
Browse files

mm: split can_change_pte_writable() into private and shared parts 

In preparation for patch 6 and modularizing the code in general, split
can_change_pte_writable() into private and shared VMA parts.  No
functional change intended.

Link: https://lkml.kernel.org/r/20250718090244.21092-6-dev.jain@arm.com


Signed-off-by: default avatarDev Jain <dev.jain@arm.com>
Suggested-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: default avatarZi Yan <ziy@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Zhenhua Huang <quic_zhenhuah@quicinc.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 57fae936

mm/mprotect.c

+36 −14
Original line number Diff line number Diff line
@@ -40,11 +40,8 @@ 


#include "internal.h"



bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,

			     pte_t pte)

static bool maybe_change_pte_writable(struct vm_area_struct *vma, pte_t pte)

{

	struct page *page;



	if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE)))

		return false;
@@ -60,7 +57,17 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, 
	if (userfaultfd_pte_wp(vma, pte))

		return false;



	if (!(vma->vm_flags & VM_SHARED)) {

	return true;

}



static bool can_change_private_pte_writable(struct vm_area_struct *vma,

					    unsigned long addr, pte_t pte)

{

	struct page *page;



	if (!maybe_change_pte_writable(vma, pte))

		return false;



	/*

	 * Writable MAP_PRIVATE mapping: We can only special-case on

	 * exclusive anonymous pages, because we know that our
@@ -71,6 +78,12 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, 
	return page && PageAnon(page) && PageAnonExclusive(page);

}



static bool can_change_shared_pte_writable(struct vm_area_struct *vma,

					   pte_t pte)

{

	if (!maybe_change_pte_writable(vma, pte))

		return false;



	VM_WARN_ON_ONCE(is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte));



	/*
@@ -83,6 +96,15 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, 
	return pte_dirty(pte);

}



bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,

			     pte_t pte)

{

	if (!(vma->vm_flags & VM_SHARED))

		return can_change_private_pte_writable(vma, addr, pte);



	return can_change_shared_pte_writable(vma, pte);

}



static int mprotect_folio_pte_batch(struct folio *folio, pte_t *ptep,

				    pte_t pte, int max_nr_ptes)

{