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authorStephen Wilson <wilsons@start.ca>2011-03-13 15:49:18 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2011-03-23 16:36:56 -0400
commite7f22e207bacdba5b73f2893a3abe935a5373e2e (patch)
tree02e9f01788742db409587475a0aa10f3a0347e38
parentcae5d39032acf26c265f6b1dc73d7ce6ff4bc387 (diff)
downloadop-kernel-dev-e7f22e207bacdba5b73f2893a3abe935a5373e2e.zip
op-kernel-dev-e7f22e207bacdba5b73f2893a3abe935a5373e2e.tar.gz
mm: use mm_struct to resolve gate vma's in __get_user_pages
We now check if a requested user page overlaps a gate vma using the supplied mm instead of the supplied task. The given task is now used solely for accounting purposes and may be NULL. Signed-off-by: Stephen Wilson <wilsons@start.ca> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--mm/memory.c18
1 files changed, 11 insertions, 7 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 5f5b5de..5f585b6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1486,9 +1486,9 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
struct vm_area_struct *vma;
vma = find_extend_vma(mm, start);
- if (!vma && in_gate_area(tsk->mm, start)) {
+ if (!vma && in_gate_area(mm, start)) {
unsigned long pg = start & PAGE_MASK;
- struct vm_area_struct *gate_vma = get_gate_vma(tsk->mm);
+ struct vm_area_struct *gate_vma = get_gate_vma(mm);
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
@@ -1589,10 +1589,13 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
return i ? i : -EFAULT;
BUG();
}
- if (ret & VM_FAULT_MAJOR)
- tsk->maj_flt++;
- else
- tsk->min_flt++;
+
+ if (tsk) {
+ if (ret & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ tsk->min_flt++;
+ }
if (ret & VM_FAULT_RETRY) {
*nonblocking = 0;
@@ -1638,7 +1641,8 @@ EXPORT_SYMBOL(__get_user_pages);
/**
* get_user_pages() - pin user pages in memory
- * @tsk: task_struct of target task
+ * @tsk: the task_struct to use for page fault accounting, or
+ * NULL if faults are not to be recorded.
* @mm: mm_struct of target mm
* @start: starting user address
* @nr_pages: number of pages from start to pin
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