From 8314c4f24a0a5c9b1f7544e9fa83a1d5367ddaa7 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 21 Sep 2009 17:02:25 -0700 Subject: ksm: remove VM_MERGEABLE_FLAGS KSM originally stood for Kernel Shared Memory: but the kernel has long supported shared memory, and VM_SHARED and VM_MAYSHARE vmas, and KSM is something else. So we switched to saying "merge" instead of "share". But Chris Wright points out that this is confusing where mmap.c merges adjacent vmas: most especially in the name VM_MERGEABLE_FLAGS, used by is_mergeable_vma() to let vmas be merged despite flags being different. Call it VMA_MERGE_DESPITE_FLAGS? Perhaps, but at present it consists only of VM_CAN_NONLINEAR: so for now it's clearer on all sides to use that directly, with a comment on it in is_mergeable_vma(). Signed-off-by: Hugh Dickins Acked-by: Izik Eidus Cc: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'mm') diff --git a/mm/mmap.c b/mm/mmap.c index ffd6c6c9bcf4..22dff49d579e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -657,9 +657,6 @@ again: remove_next = 1 + (end > next->vm_end); validate_mm(mm); } -/* Flags that can be inherited from an existing mapping when merging */ -#define VM_MERGEABLE_FLAGS (VM_CAN_NONLINEAR) - /* * If the vma has a ->close operation then the driver probably needs to release * per-vma resources, so we don't attempt to merge those. @@ -667,7 +664,8 @@ again: remove_next = 1 + (end > next->vm_end); static inline int is_mergeable_vma(struct vm_area_struct *vma, struct file *file, unsigned long vm_flags) { - if ((vma->vm_flags ^ vm_flags) & ~VM_MERGEABLE_FLAGS) + /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */ + if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR) return 0; if (vma->vm_file != file) return 0; -- cgit v1.2.3-59-g8ed1b