Re: [PATCH v2 10/40] drivers/usb/mon: update to use mmap_prepare + map kernel pages
From: sashiko-bot@kernel.org
Date: 2026-09-14 17:18:21
Also in:
bpf, dri-devel, kvm, kvmarm, linux-perf-users, linux-rdma, linux-s390, linux-scsi, selinux
Replace the deprecated .mmap hook with its replacement .mmap_prepare. As part of this change, additionally take the approach of mapping pages upon mmap rather than providing a fault handler. The page span cannot be mutated when an mmap mapping is in place, so this is safe to do in advance (the MON_IOCT_RING_SIZE ioctl operation exits -EBUSY if it's attempted, gated by the rp->mmap_active reference count). Utilise the newly introduced mmap_action_map_discontig_kernel_pages() to do this, which allows for iteration over pages in mon_bin_discontig_get(). mon_bin_discontig_init() increments the rp->mmap_active reference count to stabilise page spans. Should an error arise the core unmaps the VMA and mon_bin_vma_close() drops the reference again. [ ... ] page discarded with MADV_DONTNEED is not repopulated and a subsequent access raises SIGBUS, as with other pre-populated kernel mappings. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Sashiko has reviewed this patch and found no issues. It looks great! -- Sashiko AI review · https://sashiko.dev/#/patchset/20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org?part=10