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authorWilliam Kucharski <william.kucharski@oracle.com>2018-01-31 16:21:11 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-31 17:18:40 -0800
commitda391d640c528bc5bb227ea5b39c882b75ac3167 (patch)
tree284ee9659d8c530f61fdb6823f4fb53f0259597b
parent859d4adc3415a64ccb8b0c50dc4e3a888dcb5805 (diff)
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 commit aecd6f44266c ("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@oracle.com Signed-off-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: Larry Bassel <larry.bassel@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memory.c22
1 files changed, 11 insertions, 11 deletions
diff --git a/mm/memory.c b/mm/memory.c
index a6e5d6ac5d24..53373b7a1512 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3511,9 +3511,8 @@ static int fault_around_bytes_get(void *data, u64 *val)
}
/*
- * 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_fault *vmf)
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)) +