From da391d640c528bc5bb227ea5b39c882b75ac3167 Mon Sep 17 00:00:00 2001 From: William Kucharski Date: Wed, 31 Jan 2018 16:21:11 -0800 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 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 Reviewed-by: Larry Bassel Cc: Michal Hocko Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'mm') 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)) + -- cgit v1.2.3