mm/memory: simplify calculation in unmap_mapping_range_tree()

Let's simplify the calculation a bit further to make it easier to get,
reusing vma_last_pgoff() which we move from interval_tree.c to mm.h.

Link: https://lkml.kernel.org/r/20260227200848.114019-5-david@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Arve <arve@android.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Ahern <dsahern@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jakub Kacinski <kuba@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Todd Kjos <tkjos@android.com>
Cc: Tvrtko Ursulin <tursulin@ursulin.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

3 files changed, 10 insertions, 12 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6512d70c5852..771d021b7948 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3969,6 +3969,11 @@ static inline unsigned long vma_pages(const struct vm_area_struct *vma)
 	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 }
 
+static inline unsigned long vma_last_pgoff(struct vm_area_struct *vma)
+{
+	return vma->vm_pgoff + vma_pages(vma) - 1;
+}
+
 static inline unsigned long vma_desc_size(const struct vm_area_desc *desc)
 {
 	return desc->end - desc->start;
diff --git a/mm/interval_tree.c b/mm/interval_tree.c
index 32e390c42c53..32bcfbfcf15f 100644
--- a/mm/interval_tree.c
+++ b/mm/interval_tree.c
@@ -15,11 +15,6 @@ static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
 	return v->vm_pgoff;
 }
 
-static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
-{
-	return v->vm_pgoff + vma_pages(v) - 1;
-}
-
 INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
 		     unsigned long, shared.rb_subtree_last,
 		     vma_start_pgoff, vma_last_pgoff, /* empty */, vma_interval_tree)
diff --git a/mm/memory.c b/mm/memory.c
index f1c5d6b01a62..24b768885379 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4227,17 +4227,15 @@ static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
 					    struct zap_details *details)
 {
 	struct vm_area_struct *vma;
-	pgoff_t vba, vea, zba, zea;
 	unsigned long start, size;
 	struct mmu_gather tlb;
 
 	vma_interval_tree_foreach(vma, root, first_index, last_index) {
-		vba = vma->vm_pgoff;
-		vea = vba + vma_pages(vma) - 1;
-		zba = max(first_index, vba);
-		zea = min(last_index, vea);
-		start = ((zba - vba) << PAGE_SHIFT) + vma->vm_start;
-		size = (zea - zba + 1) << PAGE_SHIFT;
+		const pgoff_t start_idx = max(first_index, vma->vm_pgoff);
+		const pgoff_t end_idx = min(last_index, vma_last_pgoff(vma)) + 1;
+
+		start = vma->vm_start + ((start_idx - vma->vm_pgoff) << PAGE_SHIFT);
+		size = (end_idx - start_idx) << PAGE_SHIFT;
 
 		tlb_gather_mmu(&tlb, vma->vm_mm);
 		zap_page_range_single_batched(&tlb, vma, start, size, details);