From 5b23dbe8173c212d6a326e35347b038705603d39 Mon Sep 17 00:00:00 2001 From: Adam Litke Date: Wed, 14 Nov 2007 16:59:33 -0800 Subject: [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. [ezk@cs.sunysb.edu: build fix] Signed-off-by: Adam Litke Reviewed-by: Ken Chen Cc: David Gibson Cc: William Lee Irwin III Cc: Badari Pulavarty Signed-off-by: Erez Zadok Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/hugetlb.h | 4 ++-- mm/hugetlb.c | 5 +++-- mm/memory.c | 2 +- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index ea0f50bfbe0..e22368656b3 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 *); @@ -106,7 +106,7 @@ static inline unsigned long hugetlb_total_pages(void) return 0; } -#define follow_hugetlb_page(m,v,p,vs,a,b,i) ({ BUG(); 0; }) +#define follow_hugetlb_page(m,v,p,vs,a,b,i,w) ({ BUG(); 0; }) #define follow_huge_addr(mm, addr, write) ERR_PTR(-EINVAL) #define copy_hugetlb_page_range(src, dst, vma) ({ BUG(); 0; }) #define hugetlb_prefault(mapping, vma) ({ BUG(); 0; }) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 8b809ecefa3..e2c80631d36 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -868,7 +868,8 @@ 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; @@ -890,7 +891,7 @@ 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 9791e478684..7b0403bfc97 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1036,7 +1036,7 @@ 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; } -- 2.41.1