Re: [PATCH] hugetlb: follow_hugetlb_page for write access
On Wednesday 07 November 2007 20:51, Adam Litke wrote: > > 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 can cause data corruption because a device driver > that calls get_user_pages() with write set will not expect COW faults to > occur on the returned pages. > > This patch passes the write flag down to follow_hugetlb_page() and makes > sure hugetlb_fault() is called with the right write_access parameter. > > Signed-off-by: Adam Litke <[EMAIL PROTECTED]> Apologize for this late response. Tested on 2.6.23 with ehca and mthca. It works like a charm for me. Thanks! Nam - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] hugetlb: follow_hugetlb_page for write access
On Wednesday 07 November 2007 20:51, Adam Litke wrote: 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 can cause data corruption because a device driver that calls get_user_pages() with write set will not expect COW faults to occur on the returned pages. This patch passes the write flag down to follow_hugetlb_page() and makes sure hugetlb_fault() is called with the right write_access parameter. Signed-off-by: Adam Litke [EMAIL PROTECTED] Apologize for this late response. Tested on 2.6.23 with ehca and mthca. It works like a charm for me. Thanks! Nam - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] hugetlb: follow_hugetlb_page for write access
On Nov 7, 2007 11:51 AM, Adam Litke <[EMAIL PROTECTED]> wrote: > 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 can cause data corruption because a device driver > that calls get_user_pages() with write set will not expect COW faults to > occur on the returned pages. > > This patch passes the write flag down to follow_hugetlb_page() and makes > sure hugetlb_fault() is called with the right write_access parameter. > > Signed-off-by: Adam Litke <[EMAIL PROTECTED]> Adam, this looks good. Reviewed-by: Ken Chen <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] hugetlb: follow_hugetlb_page for write access
On Nov 7, 2007 11:51 AM, Adam Litke [EMAIL PROTECTED] wrote: 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 can cause data corruption because a device driver that calls get_user_pages() with write set will not expect COW faults to occur on the returned pages. This patch passes the write flag down to follow_hugetlb_page() and makes sure hugetlb_fault() is called with the right write_access parameter. Signed-off-by: Adam Litke [EMAIL PROTECTED] Adam, this looks good. Reviewed-by: Ken Chen [EMAIL PROTECTED] - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] 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 can cause data corruption because a device driver
that calls get_user_pages() with write set will not expect COW faults to
occur on the returned pages.
This patch passes the write flag down to follow_hugetlb_page() and makes
sure hugetlb_fault() is called with the right write_access parameter.
Signed-off-by: Adam Litke <[EMAIL PROTECTED]>
---
include/linux/hugetlb.h |2 +-
mm/hugetlb.c|5 +++--
mm/memory.c |2 +-
3 files changed, 5 insertions(+), 4 deletions(-)
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(>page_table_lock);
- ret = hugetlb_fault(mm, vma, vaddr, 0);
+ ret = hugetlb_fault(mm, vma, vaddr, write);
spin_lock(>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,
- , , i);
+ , , i, write);
continue;
}
-
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[PATCH] 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 can cause data corruption because a device driver
that calls get_user_pages() with write set will not expect COW faults to
occur on the returned pages.
This patch passes the write flag down to follow_hugetlb_page() and makes
sure hugetlb_fault() is called with the right write_access parameter.
Signed-off-by: Adam Litke [EMAIL PROTECTED]
---
include/linux/hugetlb.h |2 +-
mm/hugetlb.c|5 +++--
mm/memory.c |2 +-
3 files changed, 5 insertions(+), 4 deletions(-)
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;
}
-
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