The patch titled
Subject: mm: correct comments regarding do_fault_around()
has been added to the -mm tree. Its filename is
mm-correct-comments-regarding-do_fault_around.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-correct-comments-regarding-do_fault_around.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-correct-comments-regarding-do_fault_around.patch
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From: William Kucharski <william.kucharski@xxxxxxxxxx>
Subject: mm: correct comments regarding do_fault_around()
There are multiple comments surrounding do_fault_around that memtion
fault_around_pages() and fault_around_mask(), two routines that do not
exist. These comments should be reworded to reference fault_around_bytes,
the value which is used to determine how much do_fault_around() will
attempt to read when processing a fault.
These comments should have been updated when fault_around_pages() and
fault_around_mask() were removed in aecd6f44266c1 ("mm: close race between
do_fault_around() and fault_around_bytes_set()").
Fixes: aecd6f44266c1 ("mm: close race between do_fault_around() and fault_around_bytes_set()")
Link: http://lkml.kernel.org/r/302D0B14-C7E9-44C6-8BED-033F9ACBD030@xxxxxxxxxx
Signed-off-by: William Kucharski <william.kucharski@xxxxxxxxxx>
Reviewed-by: Larry Bassel <larry.bassel@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff -puN mm/memory.c~mm-correct-comments-regarding-do_fault_around mm/memory.c
--- a/mm/memory.c~mm-correct-comments-regarding-do_fault_around
+++ a/mm/memory.c
@@ -3511,9 +3511,8 @@ static int fault_around_bytes_get(void *
}
/*
- * fault_around_pages() and fault_around_mask() expects fault_around_bytes
- * rounded down to nearest page order. It's what do_fault_around() expects to
- * see.
+ * fault_around_bytes must be rounded down to the nearest page order as it's
+ * what do_fault_around() expects to see.
*/
static int fault_around_bytes_set(void *data, u64 val)
{
@@ -3556,13 +3555,14 @@ late_initcall(fault_around_debugfs);
* This function doesn't cross the VMA boundaries, in order to call map_pages()
* only once.
*
- * fault_around_pages() defines how many pages we'll try to map.
- * do_fault_around() expects it to return a power of two less than or equal to
- * PTRS_PER_PTE.
+ * fault_around_bytes defines how many bytes we'll try to map.
+ * do_fault_around() expects it to be set to a power of two less than or equal
+ * to PTRS_PER_PTE.
*
- * The virtual address of the area that we map is naturally aligned to the
- * fault_around_pages() value (and therefore to page order). This way it's
- * easier to guarantee that we don't cross page table boundaries.
+ * The virtual address of the area that we map is naturally aligned to
+ * fault_around_bytes rounded down to the machine page size
+ * (and therefore to page order). This way it's easier to guarantee
+ * that we don't cross page table boundaries.
*/
static int do_fault_around(struct vm_fault *vmf)
{
@@ -3579,8 +3579,8 @@ static int do_fault_around(struct vm_fau
start_pgoff -= off;
/*
- * end_pgoff is either end of page table or end of vma
- * or fault_around_pages() from start_pgoff, depending what is nearest.
+ * end_pgoff is either the end of the page table, the end of
+ * the vma or nr_pages from start_pgoff, depending what is nearest.
*/
end_pgoff = start_pgoff -
((vmf->address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) +
_
Patches currently in -mm which might be from william.kucharski@xxxxxxxxxx are
mm-correct-comments-regarding-do_fault_around.patch
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