Re: [PATCH 12/39] ALSA: pcm: use vm_insert_page() to map PCM status page
From: Takashi Iwai <hidden>
Date: 2026-09-10 16:15:15
Also in:
bpf, dri-devel, fuse-devel, kvm, kvm-riscv, kvmarm, linux-arch, linux-doc, linux-fbdev, linux-fsdevel, linux-mm, linux-perf-users, linux-s390, linux-scsi, linux-sound, linux-trace-kernel, linux-usb, linuxppc-dev, lkml, selinux, sparclinux
On Tue, 08 Sep 2026 22:01:16 +0200, Lorenzo Stoakes (ARM) wrote:
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 be kernel-owned; 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. Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: Takashi Iwai <redacted> thanks, Takashi