Currently the only user of mmap_region() outside of the memory management code is the MIPS VDSO implementation. This uses mmap_region() to map a 'delay slot emulation page' at the top of the stack which is read-only and executable. This mapping requires that an already-acquired mmap write lock is utilised and that uffd and populate logic is ignored. This rules out vm_mmap(), however do_mmap() fits the bill. Adapt this code to use do_mmap() and then once done, make mmap_region() internal and userland testable, and avoid any other uses of mmap_region(), which is absolutely and strictly an internal mm function which bypasses a great number of checks and logic. v1: * Stripped RFC, as Thomas indicated that the approach seemed correct from MIPS side. * Avoided whitespace error as pointed out by Matthew. * Rebased on tip mm-unstable, as previously a conflict emerged after I submitted the patch (quite possibly one I caused :P). RFC: https://lore.kernel.org/all/cover.1734017293.git.lorenzo.stoakes@xxxxxxxxxx/ Lorenzo Stoakes (2): mips: vdso: prefer do_mmap() to mmap_region() mm: make mmap_region() internal arch/mips/kernel/vdso.c | 10 +++-- include/linux/mm.h | 3 -- mm/mmap.c | 59 ----------------------------- mm/vma.c | 61 +++++++++++++++++++++++++++++- mm/vma.h | 2 +- tools/testing/vma/vma_internal.h | 65 ++++++++++++++++++++++++++++++++ 6 files changed, 132 insertions(+), 68 deletions(-) -- 2.47.1
