[RFC PATCH v2 11/19] mm/gup: Pass follow_page_context further down the call stack

ira.weiny
2019-08-09T23:01:40Z

From: Ira Weiny <ira.weiny@intel.com>

In preparation for passing more information (vaddr_pin) into
follow_page_pte(), follow_devmap_pud(), and follow_devmap_pmd().

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
include/linux/huge_mm.h | 17 -----------------
mm/gup.c | 31 +++++++++++++++----------------
mm/huge_memory.c | 6 ++++--
mm/internal.h | 28 ++++++++++++++++++++++++++++
4 files changed, 47 insertions(+), 35 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 45ede62aa85b..b01a20ce0bb9 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -233,11 +233,6 @@ static inline int hpage_nr_pages(struct page *page)
return 1;
}

-struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
- pmd_t *pmd, int flags, struct dev_pagemap **pgmap);
-struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
- pud_t *pud, int flags, struct dev_pagemap **pgmap);
-
extern vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd);

extern struct page *huge_zero_page;
@@ -375,18 +370,6 @@ static inline void mm_put_huge_zero_page(struct mm_struct *mm)
return;
}

-static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma,
- unsigned long addr, pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
-{
- return NULL;
-}
-
-static inline struct page *follow_devmap_pud(struct vm_area_struct *vma,
- unsigned long addr, pud_t *pud, int flags, struct dev_pagemap **pgmap)
-{
- return NULL;
-}
-
static inline bool thp_migration_supported(void)
{
return false;
diff --git a/mm/gup.c b/mm/gup.c
index 504af3e9a942..a7a9d2f5278c 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -24,11 +24,6 @@

#include "internal.h"

-struct follow_page_context {
- struct dev_pagemap *pgmap;
- unsigned int page_mask;
-};
-
/**
* put_user_pages_dirty_lock() - release and optionally dirty gup-pinned pages
* @pages: array of pages to be maybe marked dirty, and definitely released.
@@ -172,8 +167,9 @@ static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)

static struct page *follow_page_pte(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd, unsigned int flags,
- struct dev_pagemap **pgmap)
+ struct follow_page_context *ctx)
{
+ struct dev_pagemap **pgmap = &ctx->pgmap;
struct mm_struct *mm = vma->vm_mm;
struct page *page;
spinlock_t *ptl;
@@ -363,13 +359,13 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
}
if (pmd_devmap(pmdval)) {
ptl = pmd_lock(mm, pmd);
- page = follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap);
+ page = follow_devmap_pmd(vma, address, pmd, flags, ctx);
spin_unlock(ptl);
if (page)
return page;
}
if (likely(!pmd_trans_huge(pmdval)))
- return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
+ return follow_page_pte(vma, address, pmd, flags, ctx);

if ((flags & FOLL_NUMA) && pmd_protnone(pmdval))
return no_page_table(vma, flags);
@@ -389,7 +385,7 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
}
if (unlikely(!pmd_trans_huge(*pmd))) {
spin_unlock(ptl);
- return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
+ return follow_page_pte(vma, address, pmd, flags, ctx);
}
if (flags & (FOLL_SPLIT | FOLL_SPLIT_PMD)) {
int ret;
@@ -419,7 +415,7 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
}

return ret ? ERR_PTR(ret) :
- follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
+ follow_page_pte(vma, address, pmd, flags, ctx);
}
page = follow_trans_huge_pmd(vma, address, pmd, flags);
spin_unlock(ptl);
@@ -456,7 +452,7 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma,
}
if (pud_devmap(*pud)) {
ptl = pud_lock(mm, pud);
- page = follow_devmap_pud(vma, address, pud, flags, &ctx->pgmap);
+ page = follow_devmap_pud(vma, address, pud, flags, ctx);
spin_unlock(ptl);
if (page)
return page;
@@ -786,7 +782,8 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *nonblocking)
+ struct vm_area_struct **vmas, int *nonblocking,
+ struct vaddr_pin *vaddr_pin)
{
long ret = 0, i = 0;
struct vm_area_struct *vma = NULL;
@@ -797,6 +794,8 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,

VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));

+ ctx.vaddr_pin = vaddr_pin;
+
/*
* If FOLL_FORCE is set then do not force a full fault as the hinting
* fault information is unrelated to the reference behaviour of a task
@@ -1025,7 +1024,7 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
lock_dropped = false;
for (;;) {
ret = __get_user_pages(tsk, mm, start, nr_pages, flags, pages,
- vmas, locked);
+ vmas, locked, vaddr_pin);
if (!locked)
/* VM_FAULT_RETRY couldn't trigger, bypass */
return ret;
@@ -1068,7 +1067,7 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
lock_dropped = true;
down_read(&mm->mmap_sem);
ret = __get_user_pages(tsk, mm, start, 1, flags | FOLL_TRIED,
- pages, NULL, NULL);
+ pages, NULL, NULL, vaddr_pin);
if (ret != 1) {
BUG_ON(ret > 1);
if (!pages_done)
@@ -1226,7 +1225,7 @@ long populate_vma_page_range(struct vm_area_struct *vma,
* not result in a stack expansion that recurses back here.
*/
return __get_user_pages(current, mm, start, nr_pages, gup_flags,
- NULL, NULL, nonblocking);
+ NULL, NULL, nonblocking, NULL);
}

/*
@@ -1311,7 +1310,7 @@ struct page *get_dump_page(unsigned long addr)

if (__get_user_pages(current, current->mm, addr, 1,
FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
- NULL) < 1)
+ NULL, NULL) < 1)
return NULL;
flush_cache_page(vma, addr, page_to_pfn(page));
return page;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index bc1a07a55be1..7e09f2f17ed8 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -916,8 +916,9 @@ static void touch_pmd(struct vm_area_struct *vma, unsigned long addr,
}

struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
- pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
+ pmd_t *pmd, int flags, struct follow_page_context *ctx)
{
+ struct dev_pagemap **pgmap = &ctx->pgmap;
unsigned long pfn = pmd_pfn(*pmd);
struct mm_struct *mm = vma->vm_mm;
struct page *page;
@@ -1068,8 +1069,9 @@ static void touch_pud(struct vm_area_struct *vma, unsigned long addr,
}

struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
- pud_t *pud, int flags, struct dev_pagemap **pgmap)
+ pud_t *pud, int flags, struct follow_page_context *ctx)
{
+ struct dev_pagemap **pgmap = &ctx->pgmap;
unsigned long pfn = pud_pfn(*pud);
struct mm_struct *mm = vma->vm_mm;
struct page *page;
diff --git a/mm/internal.h b/mm/internal.h
index 0d5f720c75ab..46ada5279856 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -12,6 +12,34 @@
#include <linux/pagemap.h>
#include <linux/tracepoint-defs.h>

+struct follow_page_context {
+ struct dev_pagemap *pgmap;
+ unsigned int page_mask;
+ struct vaddr_pin *vaddr_pin;
+};
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
+ pmd_t *pmd, int flags, struct follow_page_context *ctx);
+struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
+ pud_t *pud, int flags, struct follow_page_context *ctx);
+#else
+static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma,
+ unsigned long addr, pmd_t *pmd, int flags,
+ struct follow_page_context *ctx)
+{
+ return NULL;
+}
+
+static inline struct page *follow_devmap_pud(struct vm_area_struct *vma,
+ unsigned long addr, pud_t *pud, int flags,
+ struct follow_page_context *ctx)
+{
+ return NULL;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+
/*
* The set of flags that only affect watermark checking and reclaim
* behaviour. This is used by the MM to obey the caller constraints
--
2.20.1