Re: [PATCH v4 07/38] mm: add mmap action for discontiguous kernel page mapping

On Sun, Oct 04, 2026 at 10:11:18AM -0700, Suren Baghdasaryan wrote:

On Sat, Oct 3, 2026 at 6:35 PM Lorenzo Stoakes (ARM) [off-list ref] wrote:

quoted

diff --git a/mm/memory.c b/mm/memory.c
index 448342883e9d..45b21bb04a18 100644
--- a/mm/memory.c
+++ b/mm/memory.c

quoted

+static void __map_kernel_pages_prepare(struct vm_area_desc *desc)
+{
+       if (vma_desc_test(desc, VMA_MIXEDMAP_BIT))
+               return;
+
+       VM_WARN_ON_ONCE(mmap_read_trylock(desc->mm));

Sorry I missed this before and it is pre-existing code but is this a
weird way of asserting that mmap_lock is write-locked? If so, why not
just use mmap_assert_write_locked()?

Ah yeah, this weirdness is duplicated from the existing code. Will fix up on
resin!

--
Cheers, Lorenzo