[merged mm-stable] mm-vmalloc-use-physical-page-count-in-vread_iter-for-vm_alloc-areas.patch removed from -mm tree

[merged mm-stable] mm-vmalloc-use-physical-page-count-in-vread_iter-for-vm_alloc-areas.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/vmalloc: use physical page count in vread_iter() for VM_ALLOC areas
has been removed from the -mm tree.  Its filename was
     mm-vmalloc-use-physical-page-count-in-vread_iter-for-vm_alloc-areas.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Shivam Kalra <shivamkalra98@zohomail.in>
Subject: mm/vmalloc: use physical page count in vread_iter() for VM_ALLOC areas
Date: Tue, 19 May 2026 17:42:16 +0530

For VM_ALLOC areas in vread_iter(), derive the vm area size from
vm->nr_pages rather than get_vm_area_size().

Only VM_ALLOC areas are subject to vrealloc() shrinking, which frees pages
without reducing the virtual reservation size.  Switch to using
vm->nr_pages for VM_ALLOC areas so the reader remains correct once shrink
support is added.  Other mapping types (vmap, ioremap) do not initialize
nr_pages and will continue using get_vm_area_size().

[shivamkalra98@zohomail.in: add an nr_pages check]
  Link: https://lore.kernel.org/aff47da5-4fd5-481d-be18-e1eb99639490@zohomail.in
Link: https://lore.kernel.org/20260519-vmalloc-shrink-v14-3-70b96ee3e9c9@zohomail.in
Signed-off-by: Shivam Kalra <shivamkalra98@zohomail.in>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmalloc.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/mm/vmalloc.c~mm-vmalloc-use-physical-page-count-in-vread_iter-for-vm_alloc-areas
+++ a/mm/vmalloc.c
@@ -4666,7 +4666,18 @@ long vread_iter(struct iov_iter *iter, c
 		smp_rmb();
 
 		vaddr = (char *) va->va_start;
-		size = vm ? get_vm_area_size(vm) : va_size(va);
+		if (vm)
+			/*
+			 * For VM_ALLOC areas, use nr_pages rather than
+			 * get_vm_area_size() because vrealloc() may shrink
+			 * the mapping without updating area->size. Other
+			 * mapping types (vmap, ioremap) don't set nr_pages.
+			 */
+			size = (vm->flags & VM_ALLOC && vm->nr_pages) ?
+				       (vm->nr_pages << PAGE_SHIFT) :
+				       get_vm_area_size(vm);
+		else
+			size = va_size(va);
 
 		if (addr >= vaddr + size)
 			goto next_va;
_

Patches currently in -mm which might be from shivamkalra98@zohomail.in are