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-rw-r--r--mm/nommu.c44
1 files changed, 33 insertions, 11 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
index ed75bc962fbe..2696b24f2bb3 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -34,6 +34,8 @@
#include <asm/tlb.h>
#include <asm/tlbflush.h>
+#include "internal.h"
+
void *high_memory;
struct page *mem_map;
unsigned long max_mapnr;
@@ -128,20 +130,16 @@ unsigned int kobjsize(const void *objp)
return PAGE_SIZE << compound_order(page);
}
-/*
- * get a list of pages in an address range belonging to the specified process
- * and indicate the VMA that covers each page
- * - this is potentially dodgy as we may end incrementing the page count of a
- * slab page or a secondary page from a compound page
- * - don't permit access to VMAs that don't support it, such as I/O mappings
- */
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, int len, int write, int force,
- struct page **pages, struct vm_area_struct **vmas)
+int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, int len, int flags,
+ struct page **pages, struct vm_area_struct **vmas)
{
struct vm_area_struct *vma;
unsigned long vm_flags;
int i;
+ int write = !!(flags & GUP_FLAGS_WRITE);
+ int force = !!(flags & GUP_FLAGS_FORCE);
+ int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
/* calculate required read or write permissions.
* - if 'force' is set, we only require the "MAY" flags.
@@ -156,7 +154,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
/* protect what we can, including chardevs */
if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
- !(vm_flags & vma->vm_flags))
+ (!ignore && !(vm_flags & vma->vm_flags)))
goto finish_or_fault;
if (pages) {
@@ -174,6 +172,30 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
finish_or_fault:
return i ? : -EFAULT;
}
+
+
+/*
+ * get a list of pages in an address range belonging to the specified process
+ * and indicate the VMA that covers each page
+ * - this is potentially dodgy as we may end incrementing the page count of a
+ * slab page or a secondary page from a compound page
+ * - don't permit access to VMAs that don't support it, such as I/O mappings
+ */
+int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, int len, int write, int force,
+ struct page **pages, struct vm_area_struct **vmas)
+{
+ int flags = 0;
+
+ if (write)
+ flags |= GUP_FLAGS_WRITE;
+ if (force)
+ flags |= GUP_FLAGS_FORCE;
+
+ return __get_user_pages(tsk, mm,
+ start, len, flags,
+ pages, vmas);
+}
EXPORT_SYMBOL(get_user_pages);
DEFINE_RWLOCK(vmlist_lock);