mm/rmap: remove anon_vma_merge() function

This function is confusing, we already have the concept of anon_vma merge
to adjacent VMA's anon_vma's to increase probability of anon_vma
compatibility and therefore VMA merge (see is_mergeable_anon_vma() etc.),
as well as anon_vma reuse, along side the usual VMA merge logic.

We can remove the anon_vma check as it is redundant - a merge would not
have been permitted with removal if the anon_vma's were not the same (and
in the case of an unfaulted/faulted merge, we would have already set the
unfaulted VMA's anon_vma to vp->remove->anon_vma in dup_anon_vma()).

Avoid overloading this term when we're very simply unlinking anon_vma
state from a removed VMA upon merge.

Link: https://lkml.kernel.org/r/56bbe45e309f7af197b1c4f94a9a0c8931ff2d29.1768746221.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chriscli@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index daa92a58585d9165822bd1497427374b85ffe09e..832bfc0ccfc62235e422e0d9e005a19cc4b5a401 100644 (file)
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -165,13 +165,6 @@ static inline int anon_vma_prepare(struct vm_area_struct *vma)
        return __anon_vma_prepare(vma);
 }
 
-static inline void anon_vma_merge(struct vm_area_struct *vma,
-                                 struct vm_area_struct *next)
-{
-       VM_BUG_ON_VMA(vma->anon_vma != next->anon_vma, vma);
-       unlink_anon_vmas(next);
-}
-
 struct anon_vma *folio_get_anon_vma(const struct folio *folio);
 
 #ifdef CONFIG_MM_ID

diff --git a/mm/vma.c b/mm/vma.c
index f81a5cfcd7cc15dfb22622ed93bb387661a7e9b7..6c458c8656b828c1255b007c4832d2d82c680059 100644 (file)
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -381,7 +381,7 @@ again:
                        fput(vp->file);
                }
                if (vp->remove->anon_vma)
-                       anon_vma_merge(vp->vma, vp->remove);
+                       unlink_anon_vmas(vp->remove);
                mm->map_count--;
                mpol_put(vma_policy(vp->remove));
                if (!vp->remove2)

diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
index 9f0a9f5ed0fece989b607b16877d7c4376ce3dde..93e5792306d92d15284664cf01422567ee54bd96 100644 (file)
--- a/tools/testing/vma/vma_internal.h
+++ b/tools/testing/vma/vma_internal.h
@@ -1265,11 +1265,6 @@ static inline void i_mmap_unlock_write(struct address_space *mapping)
 {
 }
 
-static inline void anon_vma_merge(struct vm_area_struct *vma,
-                                 struct vm_area_struct *next)
-{
-}
-
 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
                                         unsigned long start,
                                         unsigned long end,