mm: merge parameters for change_protection()

change_protection() was used by either the NUMA or mprotect() code, there's one parameter for each of the callers (dirty_accountable and prot_numa). Further, these parameters are passed along the calls: - change_protection_range() - change_p4d_range() - change_pud_range() - change_pmd_range() - ... Now we introduce a flag for change_protect() and all these helpers to replace these parameters. Then we can avoid passing multiple parameters multiple times along the way. More importantly, it'll greatly simplify the work if we want to introduce any new parameters to change_protection(). In the follow up patches, a new parameter for userfaultfd write protection will be introduced. No functional change at all.

Peter Xu committed 6 years ago

Commit 58705441 parent 72981e05 files · +33 −17Browse files

Unified · Split

5 files

include/linux/huge_mm.h +1 −1
include/linux/mm.h +13 −1
mm/huge_memory.c +2 −1
mm/mempolicy.c +1 −1
mm/mprotect.c +16 −13

include/linux/huge_mm.h+1−1

@@ -46,7 +46,7 @@ extern bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, · 45 unmodified lines
46	46	pmd_t old_pmd, pmd_t new_pmd);
47	47	extern int change_huge_pmd(struct vm_area_struct vma, pmd_t pmd,
48	48	unsigned long addr, pgprot_t newprot,
49		− int prot_numa);
	49	+ unsigned long cp_flags);
50	50	vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn,
51	51	pgprot_t pgprot, bool write);
52	52

include/linux/mm.h+13−1

@@ -1771,9 +1771,21 @@ extern unsigned long move_page_tables(struct vm_area_struct *vma, · 1770 unmodified lines
1771	1771	unsigned long old_addr, struct vm_area_struct *new_vma,
1772	1772	unsigned long new_addr, unsigned long len,
1773	1773	bool need_rmap_locks);
	1774	+
	1775	+/*
	1776	+ * Flags used by change_protection(). For now we make it a bitmap so
	1777	+ * that we can pass in multiple flags just like parameters. However
	1778	+ * for now all the callers are only use one of the flags at the same
	1779	+ * time.
	1780	+ */
	1781	+/* Whether we should allow dirty bit accounting */
	1782	+#define MM_CP_DIRTY_ACCT (1UL << 0)
	1783	+/* Whether this protection change is for NUMA hints */
	1784	+#define MM_CP_PROT_NUMA (1UL << 1)
	1785	+
1774	1786	extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
1775	1787	unsigned long end, pgprot_t newprot,
1776		− int dirty_accountable, int prot_numa);
	1788	+ unsigned long cp_flags);
1777	1789	extern int mprotect_fixup(struct vm_area_struct *vma,
1778	1790	struct vm_area_struct **pprev, unsigned long start,
1779	1791	unsigned long end, unsigned long newflags);

mm/huge_memory.c+2−1

@@ -1979,13 +1979,14 @@ bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, · 1978 unmodified lines
1979	1979	* - HPAGE_PMD_NR is protections changed and TLB flush necessary
1980	1980	*/
1981	1981	int change_huge_pmd(struct vm_area_struct vma, pmd_t pmd,
1982		− unsigned long addr, pgprot_t newprot, int prot_numa)
	1982	+ unsigned long addr, pgprot_t newprot, unsigned long cp_flags)
1983	1983	{
1984	1984	struct mm_struct *mm = vma->vm_mm;
1985	1985	spinlock_t *ptl;
1986	1986	pmd_t entry;
1987	1987	bool preserve_write;
1988	1988	int ret;
	1989	+ bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
1989	1990
1990	1991	ptl = __pmd_trans_huge_lock(pmd, vma);
1991	1992	if (!ptl)

mm/mempolicy.c+1−1

@@ -627,7 +627,7 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, · 626 unmodified lines
627	627	{
628	628	int nr_updated;
629	629
630		− nr_updated = change_protection(vma, addr, end, PAGE_NONE, 0, 1);
	630	+ nr_updated = change_protection(vma, addr, end, PAGE_NONE, MM_CP_PROT_NUMA);
631	631	if (nr_updated)
632	632	count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
633	633

mm/mprotect.c+16−13

@@ -37,12 +37,14 @@ · 36 unmodified lines
37	37
38	38	static unsigned long change_pte_range(struct vm_area_struct vma, pmd_t pmd,
39	39	unsigned long addr, unsigned long end, pgprot_t newprot,
40		− int dirty_accountable, int prot_numa)
	40	+ unsigned long cp_flags)
41	41	{
42	42	pte_t *pte, oldpte;
43	43	spinlock_t *ptl;
44	44	unsigned long pages = 0;
45	45	int target_node = NUMA_NO_NODE;
	46	+ bool dirty_accountable = cp_flags & MM_CP_DIRTY_ACCT;
	47	+ bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
46	48
47	49	/*
48	50	* Can be called with only the mmap_sem for reading by
@@ -188,7 +190,7 @@ static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd) · 139 unmodified lines
188	190
189	191	static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
190	192	pud_t *pud, unsigned long addr, unsigned long end,
191		− pgprot_t newprot, int dirty_accountable, int prot_numa)
	193	+ pgprot_t newprot, unsigned long cp_flags)
192	194	{
193	195	pmd_t *pmd;
194	196	unsigned long next;
@@ -229,7 +231,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, · 34 unmodified lines
229	231	__split_huge_pmd(vma, pmd, addr, false, NULL);
230	232	} else {
231	233	int nr_ptes = change_huge_pmd(vma, pmd, addr,
232		− newprot, prot_numa);
	234	+ newprot, cp_flags);
233	235
234	236	if (nr_ptes) {
235	237	if (nr_ptes == HPAGE_PMD_NR) {
@@ -244,7 +246,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, · 8 unmodified lines
244	246	/* fall through, the trans huge pmd just split */
245	247	}
246	248	this_pages = change_pte_range(vma, pmd, addr, next, newprot,
247		− dirty_accountable, prot_numa);
	249	+ cp_flags);
248	250	pages += this_pages;
249	251	next:
250	252	cond_resched();
@@ -260,7 +262,7 @@ next: · 9 unmodified lines
260	262
261	263	static inline unsigned long change_pud_range(struct vm_area_struct *vma,
262	264	p4d_t *p4d, unsigned long addr, unsigned long end,
263		− pgprot_t newprot, int dirty_accountable, int prot_numa)
	265	+ pgprot_t newprot, unsigned long cp_flags)
264	266	{
265	267	pud_t *pud;
266	268	unsigned long next;
@@ -272,7 +274,7 @@ static inline unsigned long change_pud_range(struct vm_area_struct *vma, · 5 unmodified lines
272	274	if (pud_none_or_clear_bad(pud))
273	275	continue;
274	276	pages += change_pmd_range(vma, pud, addr, next, newprot,
275		− dirty_accountable, prot_numa);
	277	+ cp_flags);
276	278	} while (pud++, addr = next, addr != end);
277	279
278	280	return pages;
@@ -280,7 +282,7 @@ static inline unsigned long change_pud_range(struct vm_area_struct *vma, · 1 unmodified line
280	282
281	283	static inline unsigned long change_p4d_range(struct vm_area_struct *vma,
282	284	pgd_t *pgd, unsigned long addr, unsigned long end,
283		− pgprot_t newprot, int dirty_accountable, int prot_numa)
	285	+ pgprot_t newprot, unsigned long cp_flags)
284	286	{
285	287	p4d_t *p4d;
286	288	unsigned long next;
@@ -292,7 +294,7 @@ static inline unsigned long change_p4d_range(struct vm_area_struct *vma, · 5 unmodified lines
292	294	if (p4d_none_or_clear_bad(p4d))
293	295	continue;
294	296	pages += change_pud_range(vma, p4d, addr, next, newprot,
295		− dirty_accountable, prot_numa);
	297	+ cp_flags);
296	298	} while (p4d++, addr = next, addr != end);
297	299
298	300	return pages;
@@ -300,7 +302,7 @@ static inline unsigned long change_p4d_range(struct vm_area_struct *vma, · 1 unmodified line
300	302
301	303	static unsigned long change_protection_range(struct vm_area_struct *vma,
302	304	unsigned long addr, unsigned long end, pgprot_t newprot,
303		− int dirty_accountable, int prot_numa)
	305	+ unsigned long cp_flags)
304	306	{
305	307	struct mm_struct *mm = vma->vm_mm;
306	308	pgd_t *pgd;
@@ -317,7 +319,7 @@ static unsigned long change_protection_range(struct vm_area_struct *vma, · 10 unmodified lines
317	319	if (pgd_none_or_clear_bad(pgd))
318	320	continue;
319	321	pages += change_p4d_range(vma, pgd, addr, next, newprot,
320		− dirty_accountable, prot_numa);
	322	+ cp_flags);
321	323	} while (pgd++, addr = next, addr != end);
322	324
323	325	/* Only flush the TLB if we actually modified any entries: */
@@ -330,14 +332,15 @@ static unsigned long change_protection_range(struct vm_area_struct *vma, · 6 unmodified lines
330	332
331	333	unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
332	334	unsigned long end, pgprot_t newprot,
333		− int dirty_accountable, int prot_numa)
	335	+ unsigned long cp_flags)
334	336	{
335	337	unsigned long pages;
336	338
337	339	if (is_vm_hugetlb_page(vma))
338	340	pages = hugetlb_change_protection(vma, start, end, newprot);
339	341	else
340		− pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa);
	342	+ pages = change_protection_range(vma, start, end, newprot,
	343	+ cp_flags);
341	344
342	345	return pages;
343	346	}
@@ -459,7 +462,7 @@ success: · 115 unmodified lines
459	462	vma_set_page_prot(vma);
460	463
461	464	change_protection(vma, start, end, vma->vm_page_prot,
462		− dirty_accountable, 0);
	465	+ dirty_accountable ? MM_CP_DIRTY_ACCT : 0);
463	466
464	467	/*
465	468	* Private VM_LOCKED VMA becoming writable: trigger COW to avoid major