From: Lorenzo Stoakes Date: Fri, 30 Aug 2024 18:10:16 +0000 (+0100) Subject: mm: remove duplicated open-coded VMA policy check X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=3e01310d29a700b99067cb0d6ba21284f2389308;p=users%2Fjedix%2Flinux-maple.git mm: remove duplicated open-coded VMA policy check Both can_vma_merge_before() and can_vma_merge_after() are invoked after checking for compatible VMA NUMA policy, we can simply move this to is_mergeable_vma() and abstract this altogether. In mmap_region() we set vmg->policy to NULL, so the policy comparisons checked in can_vma_merge_before() and can_vma_merge_after() are exactly equivalent to !vma_policy(vmg.next) and !vma_policy(vmg.prev). Equally, in do_brk_flags(), vmg->policy is NULL, so the can_vma_merge_after() is checking !vma_policy(vma), as we set vmg.prev to vma. In vma_merge(), we compare prev and next policies with vmg->policy before checking can_vma_merge_after() and can_vma_merge_before() respectively, which this patch causes to be checked in precisely the same way. This therefore maintains precisely the same logic as before, only now abstracted into is_mergeable_vma(). Link: https://lkml.kernel.org/r/0dbff286d9c4988333bc6f4ff3734cb95dd5410a.1725040657.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Acked-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Cc: Mark Brown Cc: Bert Karwatzki Cc: Jeff Xu Cc: Jiri Olsa Cc: Kees Cook Cc: Lorenzo Stoakes Cc: Matthew Wilcox Cc: "Paul E. McKenney" Cc: Paul Moore Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- diff --git a/mm/mmap.c b/mm/mmap.c index ca9c6939638b..3af8459e4e88 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1423,8 +1423,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* Attempt to expand an old mapping */ /* Check next */ - if (next && next->vm_start == end && !vma_policy(next) && - can_vma_merge_before(&vmg)) { + if (next && next->vm_start == end && can_vma_merge_before(&vmg)) { merge_end = next->vm_end; vma = next; vmg.pgoff = next->vm_pgoff - pglen; @@ -1438,8 +1437,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, } /* Check prev */ - if (prev && prev->vm_end == addr && !vma_policy(prev) && - can_vma_merge_after(&vmg)) { + if (prev && prev->vm_end == addr && can_vma_merge_after(&vmg)) { merge_start = prev->vm_start; vma = prev; vmg.pgoff = prev->vm_pgoff; @@ -1779,7 +1777,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, * Expand the existing vma if possible; Note that singular lists do not * occur after forking, so the expand will only happen on new VMAs. */ - if (vma && vma->vm_end == addr && !vma_policy(vma)) { + if (vma && vma->vm_end == addr) { VMG_STATE(vmg, mm, vmi, addr, addr + len, flags, PHYS_PFN(addr)); vmg.prev = vma; diff --git a/mm/vma.c b/mm/vma.c index 6be645240f07..3284bb778c3d 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -19,6 +19,8 @@ static inline bool is_mergeable_vma(struct vma_merge_struct *vmg, bool merge_nex */ bool may_remove_vma = merge_next; + if (!mpol_equal(vmg->policy, vma_policy(vma))) + return false; /* * VM_SOFTDIRTY should not prevent from VMA merging, if we * match the flags but dirty bit -- the caller should mark @@ -1053,17 +1055,14 @@ static struct vm_area_struct *vma_merge(struct vma_merge_struct *vmg) vma_pgoff = prev->vm_pgoff; /* Can we merge the predecessor? */ - if (addr == prev->vm_end && mpol_equal(vma_policy(prev), vmg->policy) - && can_vma_merge_after(vmg)) { - + if (addr == prev->vm_end && can_vma_merge_after(vmg)) { merge_prev = true; vma_prev(vmg->vmi); } } /* Can we merge the successor? */ - if (next && mpol_equal(vmg->policy, vma_policy(next)) && - can_vma_merge_before(vmg)) { + if (next && can_vma_merge_before(vmg)) { merge_next = true; }