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Subject[PATCH 07/64] mm/hugetlb: teach hugetlb_fault() about range locking
Date
From: Davidlohr Bueso <dave@stgolabs.net>

Such that we can pass the mmrange along to vm_fault for
page in userfault range (handle_userfault()) which gets
funky with mmap_sem - just look at the locking rules.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
include/linux/hugetlb.h | 9 +++++----
mm/gup.c | 3 ++-
mm/hugetlb.c | 16 +++++++++++-----
mm/memory.c | 2 +-
4 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 36fa6a2a82e3..df0a89a95bdc 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -91,7 +91,7 @@ int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_ar
long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
struct page **, struct vm_area_struct **,
unsigned long *, unsigned long *, long, unsigned int,
- int *);
+ int *, struct range_lock *);
void unmap_hugepage_range(struct vm_area_struct *,
unsigned long, unsigned long, struct page *);
void __unmap_hugepage_range_final(struct mmu_gather *tlb,
@@ -106,7 +106,8 @@ int hugetlb_report_node_meminfo(int, char *);
void hugetlb_show_meminfo(void);
unsigned long hugetlb_total_pages(void);
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, unsigned int flags);
+ unsigned long address, unsigned int flags,
+ struct range_lock *mmrange);
int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
@@ -170,7 +171,7 @@ static inline unsigned long hugetlb_total_pages(void)
return 0;
}

-#define follow_hugetlb_page(m,v,p,vs,a,b,i,w,n) ({ BUG(); 0; })
+#define follow_hugetlb_page(m,v,p,vs,a,b,i,w,n,r) ({ BUG(); 0; })
#define follow_huge_addr(mm, addr, write) ERR_PTR(-EINVAL)
#define copy_hugetlb_page_range(src, dst, vma) ({ BUG(); 0; })
static inline void hugetlb_report_meminfo(struct seq_file *m)
@@ -189,7 +190,7 @@ static inline void hugetlb_show_meminfo(void)
#define pud_huge(x) 0
#define is_hugepage_only_range(mm, addr, len) 0
#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; })
-#define hugetlb_fault(mm, vma, addr, flags) ({ BUG(); 0; })
+#define hugetlb_fault(mm, vma, addr, flags,mmrange) ({ BUG(); 0; })
#define hugetlb_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
src_addr, pagep) ({ BUG(); 0; })
#define huge_pte_offset(mm, address, sz) 0
diff --git a/mm/gup.c b/mm/gup.c
index 01983a7b3750..3d1b6dd11616 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -684,7 +684,8 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
&start, &nr_pages, i,
- gup_flags, nonblocking);
+ gup_flags, nonblocking,
+ mmrange);
continue;
}
}
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 7c204e3d132b..fd22459e89ef 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3675,7 +3675,8 @@ int huge_add_to_page_cache(struct page *page, struct address_space *mapping,

static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct address_space *mapping, pgoff_t idx,
- unsigned long address, pte_t *ptep, unsigned int flags)
+ unsigned long address, pte_t *ptep, unsigned int flags,
+ struct range_lock *mmrange)
{
struct hstate *h = hstate_vma(vma);
int ret = VM_FAULT_SIGBUS;
@@ -3716,6 +3717,7 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
.vma = vma,
.address = address,
.flags = flags,
+ .lockrange = mmrange,
/*
* Hard to debug if it ends up being
* used by a callee that assumes
@@ -3869,7 +3871,8 @@ u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
#endif

int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, unsigned int flags)
+ unsigned long address, unsigned int flags,
+ struct range_lock *mmrange)
{
pte_t *ptep, entry;
spinlock_t *ptl;
@@ -3912,7 +3915,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,

entry = huge_ptep_get(ptep);
if (huge_pte_none(entry)) {
- ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
+ ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep,
+ flags, mmrange);
goto out_mutex;
}

@@ -4140,7 +4144,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
unsigned long *position, unsigned long *nr_pages,
- long i, unsigned int flags, int *nonblocking)
+ long i, unsigned int flags, int *nonblocking,
+ struct range_lock *mmrange)
{
unsigned long pfn_offset;
unsigned long vaddr = *position;
@@ -4221,7 +4226,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
FAULT_FLAG_ALLOW_RETRY);
fault_flags |= FAULT_FLAG_TRIED;
}
- ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
+ ret = hugetlb_fault(mm, vma, vaddr, fault_flags,
+ mmrange);
if (ret & VM_FAULT_ERROR) {
err = vm_fault_to_errno(ret, flags);
remainder = 0;
diff --git a/mm/memory.c b/mm/memory.c
index b3561a052939..2d087b0e174d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4136,7 +4136,7 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
mem_cgroup_oom_enable();

if (unlikely(is_vm_hugetlb_page(vma)))
- ret = hugetlb_fault(vma->vm_mm, vma, address, flags);
+ ret = hugetlb_fault(vma->vm_mm, vma, address, flags, mmrange);
else
ret = __handle_mm_fault(vma, address, flags, mmrange);

--
2.13.6
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