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Subject[PATCH v2 1/3] fix mm: use long type for page counts in mm_populate() and get_user_pages()
Date
Andrew suggested I make the nr_pages argument an unsigned long rather
than just a long. I was initially worried that nr_pages would be compared
with signed longs, but this isn't the case, so his suggestion is perfectly
valid.

Sending as a 'fix' change, to be collapsed with the original in -mm.

Signed-off-by: Michel Lespinasse <walken@google.com>

---
include/linux/hugetlb.h | 2 +-
include/linux/mm.h | 11 ++++++-----
mm/hugetlb.c | 8 ++++----
mm/memory.c | 12 ++++++------
mm/mlock.c | 2 +-
5 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index fc6ed17cfd17..eedc334fb6f5 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -45,7 +45,7 @@ int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int,
int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
struct page **, struct vm_area_struct **,
- unsigned long *, long *, long, unsigned int flags);
+ unsigned long *, unsigned long *, long, unsigned int);
void unmap_hugepage_range(struct vm_area_struct *,
unsigned long, unsigned long, struct page *);
void __unmap_hugepage_range_final(struct mmu_gather *tlb,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d5716094f191..3d9fbcf9fa94 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1041,12 +1041,13 @@ extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
void *buf, int len, int write);

long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, long len, unsigned int foll_flags,
- struct page **pages, struct vm_area_struct **vmas,
- int *nonblocking);
+ unsigned long start, unsigned long nr_pages,
+ unsigned int foll_flags, struct page **pages,
+ struct vm_area_struct **vmas, int *nonblocking);
long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, long nr_pages, int write, int force,
- struct page **pages, struct vm_area_struct **vmas);
+ unsigned long start, unsigned long nr_pages,
+ int write, int force, struct page **pages,
+ struct vm_area_struct **vmas);
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages);
struct kvec;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4ad07221ce60..951873c8f57e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2926,12 +2926,12 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address,

long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
- unsigned long *position, long *length, long i,
- unsigned int flags)
+ unsigned long *position, unsigned long *nr_pages,
+ long i, unsigned int flags)
{
unsigned long pfn_offset;
unsigned long vaddr = *position;
- long remainder = *length;
+ unsigned long remainder = *nr_pages;
struct hstate *h = hstate_vma(vma);

spin_lock(&mm->page_table_lock);
@@ -3001,7 +3001,7 @@ same_page:
}
}
spin_unlock(&mm->page_table_lock);
- *length = remainder;
+ *nr_pages = remainder;
*position = vaddr;

return i ? i : -EFAULT;
diff --git a/mm/memory.c b/mm/memory.c
index 381b78c20d84..f0b6b2b798c4 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1674,14 +1674,14 @@ static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long add
* you need some special @gup_flags.
*/
long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, long nr_pages, unsigned int gup_flags,
- struct page **pages, struct vm_area_struct **vmas,
- int *nonblocking)
+ unsigned long start, unsigned long nr_pages,
+ unsigned int gup_flags, struct page **pages,
+ struct vm_area_struct **vmas, int *nonblocking)
{
long i;
unsigned long vm_flags;

- if (nr_pages <= 0)
+ if (!nr_pages)
return 0;

VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
@@ -1978,8 +1978,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
* See also get_user_pages_fast, for performance critical applications.
*/
long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, long nr_pages, int write, int force,
- struct page **pages, struct vm_area_struct **vmas)
+ unsigned long start, unsigned long nr_pages, int write,
+ int force, struct page **pages, struct vm_area_struct **vmas)
{
int flags = FOLL_TOUCH;

diff --git a/mm/mlock.c b/mm/mlock.c
index e1fa9e4b0a66..6baaf4b0e591 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -160,7 +160,7 @@ long __mlock_vma_pages_range(struct vm_area_struct *vma,
{
struct mm_struct *mm = vma->vm_mm;
unsigned long addr = start;
- long nr_pages = (end - start) / PAGE_SIZE;
+ unsigned long nr_pages = (end - start) / PAGE_SIZE;
int gup_flags;

VM_BUG_ON(start & ~PAGE_MASK);
--
1.8.1

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