Re: [PATCH v4 19/38] HSI: cmt_speech: convert mmap hook to mmap_prepare, refactor
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From: Suren Baghdasaryan <surenb@google.com>
Date: 2026-10-04 18:09:54
Also in:
bpf, fuse-devel, kvm, kvm-riscv, kvmarm, linux-arch, linux-doc, linux-fbdev, linux-fsdevel, linux-mm, linux-perf-users, linux-rdma, linux-riscv, linux-s390, linux-scsi, linux-sound, linux-usb, linuxppc-dev, lkml, selinux, sparclinux
On Sat, Oct 3, 2026 at 6:39 PM Lorenzo Stoakes (ARM) [off-list ref] wrote:
Use the mmap_prepare in favour of the deprecated mmap hook as part of the work to convert one to another. Since this is simply a refcounted kernel page that has been allocated, it should not be marked VM_IO and should be inserted using the kernel page insertion mechanism, so convert it to do this instead. Use the VMA descriptor's private data field as a scratch buffer to store the page in - this stays valid throughout the kernel page mapping operation. Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
quoted hunk ↗ jump to hunk
--- drivers/hsi/clients/cmt_speech.c | 33 +++++++++------------------------ 1 file changed, 9 insertions(+), 24 deletions(-)diff --git a/drivers/hsi/clients/cmt_speech.c b/drivers/hsi/clients/cmt_speech.c index 7226677ebde7..801697b74d4f 100644 --- a/drivers/hsi/clients/cmt_speech.c +++ b/drivers/hsi/clients/cmt_speech.c@@ -1084,22 +1084,6 @@ static void cs_hsi_stop(struct cs_hsi_iface *hi) kfree(hi); } -static vm_fault_t cs_char_vma_fault(struct vm_fault *vmf) -{ - struct cs_char *csdata = vmf->vma->vm_private_data; - struct page *page; - - page = virt_to_page((void *)csdata->mmap_base); - get_page(page); - vmf->page = page; - - return 0; -} - -static const struct vm_operations_struct cs_char_vm_ops = { - .fault = cs_char_vma_fault, -}; - static int cs_char_fasync(int fd, struct file *file, int on) { struct cs_char *csdata = file->private_data;@@ -1256,18 +1240,19 @@ static long cs_char_ioctl(struct file *file, unsigned int cmd, return r; } -static int cs_char_mmap(struct file *file, struct vm_area_struct *vma) +static int cs_char_mmap_prepare(struct vm_area_desc *desc) { - if (vma->vm_end < vma->vm_start) - return -EINVAL; + struct file *file = desc->file; + struct cs_char *csdata = file->private_data; + struct page **pages = (struct page **)&desc->private_data; - if (vma_pages(vma) != 1) + if (vma_desc_pages(desc) != 1) return -EINVAL; - vm_flags_set(vma, VM_IO | VM_DONTDUMP | VM_DONTEXPAND); - vma->vm_ops = &cs_char_vm_ops; - vma->vm_private_data = file->private_data; + vma_desc_set_flags(desc, VMA_DONTDUMP_BIT, VMA_DONTEXPAND_BIT); + *pages = virt_to_page((void *)csdata->mmap_base); + mmap_action_map_kernel_pages_full(desc, pages); return 0; }@@ -1353,7 +1338,7 @@ static const struct file_operations cs_char_fops = { .write = cs_char_write, .poll = cs_char_poll, .unlocked_ioctl = cs_char_ioctl, - .mmap = cs_char_mmap, + .mmap_prepare = cs_char_mmap_prepare, .open = cs_char_open, .release = cs_char_release, .fasync = cs_char_fasync, --2.55.0