Please try this patch and see if it helps.
commit 6decbd17d6fb70d50f6db2c348bb41d7246a67d1
Author: Adam Litke <[EMAIL PROTECTED]>
Date: Tue Nov 6 06:59:12 2007 -0800
hugetlb: follow_hugetlb_page for write access
When calling get_user_pages(), a write flag is passed in by the caller to
indicate if write access is required on the faulted-in pages. Currently,
follow_hugetlb_page() ignores this flag and always faults pages for
read-only access.
This patch passes the write flag down to follow_hugetlb_page() and makes
sure hugetlb_fault() is called with the right write_access parameter.
Test patch only. Not Signed-off.
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 3a19b03..31fa0a0 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -19,7 +19,7 @@ static inline int is_vm_hugetlb_page(struct vm_area_struct
*vma)
int hugetlb_sysctl_handler(struct ctl_table *, int, struct file *, void __user
*, size_t *, loff_t *);
int hugetlb_treat_movable_handler(struct ctl_table *, int, struct file *, void
__user *, size_t *, loff_t *);
int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct
vm_area_struct *);
-int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct
page **, struct vm_area_struct **, unsigned long *, int *, int);
+int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct
page **, struct vm_area_struct **, unsigned long *, int *, int, int);
void unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned
long);
void __unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned
long);
int hugetlb_prefault(struct address_space *, struct vm_area_struct *);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index eab8c42..b645985 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -621,7 +621,8 @@ int hugetlb_fault(struct mm_struct *mm, struct
vm_area_struct *vma,
int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
- unsigned long *position, int *length, int i)
+ unsigned long *position, int *length, int i,
+ int write)
{
unsigned long pfn_offset;
unsigned long vaddr = *position;
@@ -643,7 +644,7 @@ int follow_hugetlb_page(struct mm_struct *mm, struct
vm_area_struct *vma,
int ret;
spin_unlock(&mm->page_table_lock);
- ret = hugetlb_fault(mm, vma, vaddr, 0);
+ ret = hugetlb_fault(mm, vma, vaddr, write);
spin_lock(&mm->page_table_lock);
if (!(ret & VM_FAULT_ERROR))
continue;
diff --git a/mm/memory.c b/mm/memory.c
index f82b359..1bcd444 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1039,7 +1039,7 @@ int 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, &len, i);
+ &start, &len, i, write);
continue;
}
On Tue, 2007-11-06 at 08:42 +0100, Christoph Raisch wrote:
> Hello,
> if get_user_pages is used on a hugetlb vma, and there was no previous write
> to the pages,
> follow_hugetlb_page will call
> ret = hugetlb_fault(mm, vma, vaddr, 0),
> although the page should be used for write access in get_user_pages.
>
> We currently see this when testing Infiniband on ppc64 with ehca +
> hugetlbfs.
> From reading the code this should also be an issue on other architectures.
> Roland, Adam, are you aware of anything in this area with mellanox
> Infiniband cards or other usages with I/O adapters?
>
> Gruss / Regards
> Christoph R. + Nam Ng.
>
>
--
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center
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