Re: [PATCH v4 12/38] ALSA: pcm: use vm_insert_page() to map PCM status page

There's no need to keep a fault handler around for this, instead map on
mmap.

While we're here, rename area to vma to be consistent.

This correctly makes the mapping a mixed map mapping.

This works towards establishing the invariant that only PFN mapped or mixed
map mappings may clear the VM_MAYWRITE flag. The status page mapping clears
VM_MAYWRITE, so it must not be mm-managed; the control page mapping remains
writable and is left fault-based.

The assumption is made that the struct pcm_mmap_status structure is at most
a page in size, which is asserted as a build bug.

This is safe to assume, as the size of the structure is 56 bytes at most.

Acked-by: Takashi Iwai <redacted>
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261003-b4-mmap-prepare-vma-flag-sanify-v4-0-a1f052500fd7@kernel.org?part=12