[RFC PATCH v2 10/19] mm/gup: Pass a NULL vaddr_pin through GUP fast

From: ira . weiny
Date: Fri Aug 09 2019 - 18:59:04 EST

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From: Ira Weiny <ira.weiny@xxxxxxxxx>

Internally GUP fast needs to know that fast users will not support file
pins. Pass NULL for vaddr_pin through the fast call stack so that the
pin code can return an error if it encounters file backed memory within
the address range.

Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
mm/gup.c | 65 ++++++++++++++++++++++++++++++++++----------------------
1 file changed, 40 insertions(+), 25 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 7a449500f0a6..504af3e9a942 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1813,7 +1813,8 @@ static inline struct page *try_get_compound_head(struct page *page, int refs)

#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
+ unsigned int flags, struct page **pages, int *nr,
+ struct vaddr_pin *vaddr_pin)
{
struct dev_pagemap *pgmap = NULL;
int nr_start = *nr, ret = 0;
@@ -1894,7 +1895,8 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
* useful to have gup_huge_pmd even if we can't operate on ptes.
*/
static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
+ unsigned int flags, struct page **pages, int *nr,
+ struct vaddr_pin *vaddr_pin)
{
return 0;
}
@@ -1903,7 +1905,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
#if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
static int __gup_device_huge(unsigned long pfn, unsigned long addr,
unsigned long end, struct page **pages, int *nr,
- unsigned int flags)
+ unsigned int flags, struct vaddr_pin *vaddr_pin)
{
int nr_start = *nr;
struct dev_pagemap *pgmap = NULL;
@@ -1938,13 +1940,14 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr,

static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
unsigned long end, struct page **pages, int *nr,
- unsigned int flags)
+ unsigned int flags, struct vaddr_pin *vaddr_pin)
{
unsigned long fault_pfn;
int nr_start = *nr;

fault_pfn = pmd_pfn(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
- if (!__gup_device_huge(fault_pfn, addr, end, pages, nr, flags))
+ if (!__gup_device_huge(fault_pfn, addr, end, pages, nr, flags,
+ vaddr_pin))
return 0;

if (unlikely(pmd_val(orig) != pmd_val(*pmdp))) {
@@ -1957,13 +1960,14 @@ static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,

static int __gup_device_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
unsigned long end, struct page **pages, int *nr,
- unsigned int flags)
+ unsigned int flags, struct vaddr_pin *vaddr_pin)
{
unsigned long fault_pfn;
int nr_start = *nr;

fault_pfn = pud_pfn(orig) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
- if (!__gup_device_huge(fault_pfn, addr, end, pages, nr, flags))
+ if (!__gup_device_huge(fault_pfn, addr, end, pages, nr, flags,
+ vaddr_pin))
return 0;

if (unlikely(pud_val(orig) != pud_val(*pudp))) {
@@ -1975,7 +1979,7 @@ static int __gup_device_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
#else
static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
unsigned long end, struct page **pages, int *nr,
- unsigned int flags)
+ unsigned int flags, struct vaddr_pin *vaddr_pin)
{
BUILD_BUG();
return 0;
@@ -1983,7 +1987,7 @@ static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,

static int __gup_device_huge_pud(pud_t pud, pud_t *pudp, unsigned long addr,
unsigned long end, struct page **pages, int *nr,
- unsigned int flags)
+ unsigned int flags, struct vaddr_pin *vaddr_pin)
{
BUILD_BUG();
return 0;
@@ -2075,7 +2079,8 @@ static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
#endif /* CONFIG_ARCH_HAS_HUGEPD */

static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
- unsigned long end, unsigned int flags, struct page **pages, int *nr)
+ unsigned long end, unsigned int flags, struct page **pages,
+ int *nr, struct vaddr_pin *vaddr_pin)
{
struct page *head, *page;
int refs;
@@ -2087,7 +2092,7 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
if (unlikely(flags & FOLL_LONGTERM))
return 0;
return __gup_device_huge_pmd(orig, pmdp, addr, end, pages, nr,
- flags);
+ flags, vaddr_pin);
}

refs = 0;
@@ -2117,7 +2122,8 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
}

static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
- unsigned long end, unsigned int flags, struct page **pages, int *nr)
+ unsigned long end, unsigned int flags, struct page **pages, int *nr,
+ struct vaddr_pin *vaddr_pin)
{
struct page *head, *page;
int refs;
@@ -2129,7 +2135,7 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
if (unlikely(flags & FOLL_LONGTERM))
return 0;
return __gup_device_huge_pud(orig, pudp, addr, end, pages, nr,
- flags);
+ flags, vaddr_pin);
}

refs = 0;
@@ -2196,7 +2202,8 @@ static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr,
}

static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
+ unsigned int flags, struct page **pages, int *nr,
+ struct vaddr_pin *vaddr_pin)
{
unsigned long next;
pmd_t *pmdp;
@@ -2220,7 +2227,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
return 0;

if (!gup_huge_pmd(pmd, pmdp, addr, next, flags,
- pages, nr))
+ pages, nr, vaddr_pin))
return 0;

} else if (unlikely(is_hugepd(__hugepd(pmd_val(pmd))))) {
@@ -2231,7 +2238,8 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
if (!gup_huge_pd(__hugepd(pmd_val(pmd)), addr,
PMD_SHIFT, next, flags, pages, nr))
return 0;
- } else if (!gup_pte_range(pmd, addr, next, flags, pages, nr))
+ } else if (!gup_pte_range(pmd, addr, next, flags, pages, nr,
+ vaddr_pin))
return 0;
} while (pmdp++, addr = next, addr != end);

@@ -2239,7 +2247,8 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
}

static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
+ unsigned int flags, struct page **pages, int *nr,
+ struct vaddr_pin *vaddr_pin)
{
unsigned long next;
pud_t *pudp;
@@ -2253,13 +2262,14 @@ static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
return 0;
if (unlikely(pud_huge(pud))) {
if (!gup_huge_pud(pud, pudp, addr, next, flags,
- pages, nr))
+ pages, nr, vaddr_pin))
return 0;
} else if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) {
if (!gup_huge_pd(__hugepd(pud_val(pud)), addr,
PUD_SHIFT, next, flags, pages, nr))
return 0;
- } else if (!gup_pmd_range(pud, addr, next, flags, pages, nr))
+ } else if (!gup_pmd_range(pud, addr, next, flags, pages, nr,
+ vaddr_pin))
return 0;
} while (pudp++, addr = next, addr != end);

@@ -2267,7 +2277,8 @@ static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
}

static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
+ unsigned int flags, struct page **pages, int *nr,
+ struct vaddr_pin *vaddr_pin)
{
unsigned long next;
p4d_t *p4dp;
@@ -2284,7 +2295,8 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end,
if (!gup_huge_pd(__hugepd(p4d_val(p4d)), addr,
P4D_SHIFT, next, flags, pages, nr))
return 0;
- } else if (!gup_pud_range(p4d, addr, next, flags, pages, nr))
+ } else if (!gup_pud_range(p4d, addr, next, flags, pages, nr,
+ vaddr_pin))
return 0;
} while (p4dp++, addr = next, addr != end);

@@ -2292,7 +2304,8 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end,
}

static void gup_pgd_range(unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
+ unsigned int flags, struct page **pages, int *nr,
+ struct vaddr_pin *vaddr_pin)
{
unsigned long next;
pgd_t *pgdp;
@@ -2312,7 +2325,8 @@ static void gup_pgd_range(unsigned long addr, unsigned long end,
if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr,
PGDIR_SHIFT, next, flags, pages, nr))
return;
- } else if (!gup_p4d_range(pgd, addr, next, flags, pages, nr))
+ } else if (!gup_p4d_range(pgd, addr, next, flags, pages, nr,
+ vaddr_pin))
return;
} while (pgdp++, addr = next, addr != end);
}
@@ -2374,7 +2388,8 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
if (IS_ENABLED(CONFIG_HAVE_FAST_GUP) &&
gup_fast_permitted(start, end)) {
local_irq_save(flags);
- gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr);
+ gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr,
+ NULL);
local_irq_restore(flags);
}

@@ -2445,7 +2460,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages,
if (IS_ENABLED(CONFIG_HAVE_FAST_GUP) &&
gup_fast_permitted(start, end)) {
local_irq_disable();
- gup_pgd_range(addr, end, gup_flags, pages, &nr);
+ gup_pgd_range(addr, end, gup_flags, pages, &nr, NULL);
local_irq_enable();
ret = nr;
}
--
2.20.1

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