On Tue, Jun 30, 2026 at 05:36:18PM +0100, Pedro Falcato wrote: > On Mon, Jun 29, 2026 at 01:23:23PM +0100, Lorenzo Stoakes wrote: > > Break up the existing very large conditional, add comments and use > > vma_[start/end]_pgoff() to make clearer what we're doing here. > > > > No functional change intended. > > > > Signed-off-by: Lorenzo Stoakes <[email protected]> > > --- > > mm/vma.c | 21 ++++++++++++++++----- > > 1 file changed, 16 insertions(+), 5 deletions(-) > > > > diff --git a/mm/vma.c b/mm/vma.c > > index b60375c6c5c3..6296acecf3b7 100644 > > --- a/mm/vma.c > > +++ b/mm/vma.c > > @@ -1967,14 +1967,25 @@ static int anon_vma_compatible(struct > > vm_area_struct *a, struct vm_area_struct * > > { > > vma_flags_t diff = vma_flags_diff_pair(&a->flags, &b->flags); > > > > + /* Ignore flags that mprotect() can change. */ > > vma_flags_clear_mask(&diff, VMA_ACCESS_FLAGS); > > + /* Ignore flags that do not impact merging. */ > > vma_flags_clear_mask(&diff, VMA_IGNORE_MERGE_FLAGS); > > > > - return a->vm_end == b->vm_start && > > - mpol_equal(vma_policy(a), vma_policy(b)) && > > - a->vm_file == b->vm_file && > > - vma_flags_empty(&diff) && > > - b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> > > PAGE_SHIFT); > > + /* Must be adjacent. */ > > + if (a->vm_end != b->vm_start) > > + return false; > > + /* Must have matching policy. */ > > + if (!mpol_equal(vma_policy(a), vma_policy(b))) > > + return false; > > + /* Must both be anon or map the same file (MAP_PRIVATE case). */ > > + if (a->vm_file != b->vm_file) > > + return false; > > + /* Flags must be equivalent modulo mprotect(). */ > > + if (!vma_flags_empty(&diff)) > > + return false; > > + /* Page offset must align. */ > > + return vma_end_pgoff(a) == vma_start_pgoff(b); > > Very nice. > > Reviewed-by: Pedro Falcato <[email protected]>
Thanks :) > > -- > Pedro Cheers, Lorenzo
