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-rw-r--r--mm/hmm.c31
1 files changed, 17 insertions, 14 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index 84e0577a912a..bd957a9f10d1 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -702,23 +702,25 @@ static void hmm_pfns_special(struct hmm_range *range)
}
/*
- * hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses
- * @range: range being snapshotted
- * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid
- * vma permission, 0 success
+ * hmm_range_snapshot() - snapshot CPU page table for a range
+ * @range: range
+ * Returns: number of valid pages in range->pfns[] (from range start
+ * address). This may be zero. If the return value is negative,
+ * then one of the following values may be returned:
+ *
+ * -EINVAL invalid arguments or mm or virtual address are in an
+ * invalid vma (ie either hugetlbfs or device file vma).
+ * -EPERM For example, asking for write, when the range is
+ * read-only
+ * -EAGAIN Caller needs to retry
+ * -EFAULT Either no valid vma exists for this range, or it is
+ * illegal to access the range
*
* This snapshots the CPU page table for a range of virtual addresses. Snapshot
* validity is tracked by range struct. See hmm_vma_range_done() for further
* information.
- *
- * The range struct is initialized here. It tracks the CPU page table, but only
- * if the function returns success (0), in which case the caller must then call
- * hmm_vma_range_done() to stop CPU page table update tracking on this range.
- *
- * NOT CALLING hmm_vma_range_done() IF FUNCTION RETURNS 0 WILL LEAD TO SERIOUS
- * MEMORY CORRUPTION ! YOU HAVE BEEN WARNED !
*/
-int hmm_vma_get_pfns(struct hmm_range *range)
+long hmm_range_snapshot(struct hmm_range *range)
{
struct vm_area_struct *vma = range->vma;
struct hmm_vma_walk hmm_vma_walk;
@@ -772,6 +774,7 @@ int hmm_vma_get_pfns(struct hmm_range *range)
hmm_vma_walk.fault = false;
hmm_vma_walk.range = range;
mm_walk.private = &hmm_vma_walk;
+ hmm_vma_walk.last = range->start;
mm_walk.vma = vma;
mm_walk.mm = vma->vm_mm;
@@ -788,9 +791,9 @@ int hmm_vma_get_pfns(struct hmm_range *range)
* function return 0).
*/
range->hmm = hmm;
- return 0;
+ return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT;
}
-EXPORT_SYMBOL(hmm_vma_get_pfns);
+EXPORT_SYMBOL(hmm_range_snapshot);
/*
* hmm_vma_range_done() - stop tracking change to CPU page table over a range