2019-06-06 01:46:56

by Ira Weiny

Subject: [PATCH RFC 03/10] mm/gup: Pass flags down to __gup_device_huge* calls

From: Ira Weiny <[email protected]>

In order to support checking for a layout lease on a FS DAX inode these
calls need to know if FOLL_LONGTERM was specified.

Prepare for this with this patch.

Signed-off-by: Ira Weiny <[email protected]>
---
mm/gup.c | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index a3fb48605836..26a7a3a3a657 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1939,7 +1939,8 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,

#if defined(__HAVE_ARCH_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 long end, struct page **pages, int *nr,
+ unsigned int flags)
{
int nr_start = *nr;
struct dev_pagemap *pgmap = NULL;
@@ -1969,30 +1970,33 @@ 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 long end, struct page **pages, int *nr,
+ unsigned int flags)
{
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))
+ if (!__gup_device_huge(fault_pfn, addr, end, pages, nr, flags))
return 0;

if (unlikely(pmd_val(orig) != pmd_val(*pmdp))) {
undo_dev_pagemap(nr, nr_start, pages);
return 0;
}
+
return 1;
}

static int __gup_device_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
- unsigned long end, struct page **pages, int *nr)
+ unsigned long end, struct page **pages, int *nr,
+ unsigned int flags)
{
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))
+ if (!__gup_device_huge(fault_pfn, addr, end, pages, nr, flags))
return 0;

if (unlikely(pud_val(orig) != pud_val(*pudp))) {
@@ -2003,14 +2007,16 @@ 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 long end, struct page **pages, int *nr,
+ unsigned int flags)
{
BUILD_BUG();
return 0;
}

static int __gup_device_huge_pud(pud_t pud, pud_t *pudp, unsigned long addr,
- unsigned long end, struct page **pages, int *nr)
+ unsigned long end, struct page **pages, int *nr,
+ unsigned int flags)
{
BUILD_BUG();
return 0;
@@ -2029,7 +2035,8 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
if (pmd_devmap(orig)) {
if (unlikely(flags & FOLL_LONGTERM))
return 0;
- return __gup_device_huge_pmd(orig, pmdp, addr, end, pages, nr);
+ return __gup_device_huge_pmd(orig, pmdp, addr, end, pages, nr,
+ flags);
}

refs = 0;
@@ -2072,7 +2079,8 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
if (pud_devmap(orig)) {
if (unlikely(flags & FOLL_LONGTERM))
return 0;
- return __gup_device_huge_pud(orig, pudp, addr, end, pages, nr);
+ return __gup_device_huge_pud(orig, pudp, addr, end, pages, nr,
+ flags);
}

refs = 0;
--
2.20.1

2019-06-06 06:19:32

by Christoph Hellwig

Subject: Re: [PATCH RFC 03/10] mm/gup: Pass flags down to __gup_device_huge* calls

On Wed, Jun 05, 2019 at 06:45:36PM -0700, [email protected] wrote:
> From: Ira Weiny <[email protected]>
>
> In order to support checking for a layout lease on a FS DAX inode these
> calls need to know if FOLL_LONGTERM was specified.
>
> Prepare for this with this patch.

The GUP fast argument passing is a mess. That is why I've come up
with this as part of the (not ready) get_user_pages_fast_bvec
implementation:

http://git.infradead.org/users/hch/misc.git/commitdiff/c3d019802dbde5a4cc4160e7ec8ccba479b19f97