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SubjectRe: [PATCH] tee: make tee_shm_register_kernel_buf vmalloc supported
On Sun, Feb 13, 2022 at 5:21 PM Phil Chang <phil.chang@mediatek.com> wrote:
>
> In some low-memory devices, it's hard to aquire large-orders pages,
> this patch allowed user using scatter pages to register shm.
>
> Signed-off-by: Phil Chang <phil.chang@mediatek.com>
> ---
> drivers/tee/optee/call.c | 2 +-
> drivers/tee/tee_shm.c | 40 ++++++++++++++++++++++++++++------------
> 2 files changed, 29 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
> index bd49ec934060..2082e632adff 100644
> --- a/drivers/tee/optee/call.c
> +++ b/drivers/tee/optee/call.c
> @@ -362,7 +362,7 @@ int optee_check_mem_type(unsigned long start, size_t num_pages)
> * Allow kernel address to register with OP-TEE as kernel
> * pages are configured as normal memory only.
> */
> - if (virt_addr_valid(start))
> + if (virt_addr_valid(start) || is_vmalloc_addr((void *)start))
> return 0;
>
> mmap_read_lock(mm);
> diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> index f31e29e8f1ca..861403588485 100644
> --- a/drivers/tee/tee_shm.c
> +++ b/drivers/tee/tee_shm.c
> @@ -23,22 +23,38 @@ static void shm_put_kernel_pages(struct page **pages, size_t page_count)
> static int shm_get_kernel_pages(unsigned long start, size_t page_count,
> struct page **pages)
> {
> - struct kvec *kiov;
> - size_t n;
> int rc;
>
> - kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL);
> - if (!kiov)
> - return -ENOMEM;
> -
> - for (n = 0; n < page_count; n++) {
> - kiov[n].iov_base = (void *)(start + n * PAGE_SIZE);
> - kiov[n].iov_len = PAGE_SIZE;
> + if (is_vmalloc_addr((void *)start)) {
> + struct page *page;
> + int i;
> +
> + for (i = 0; i < page_count; i++) {

page_count is of an unsigned type and i is of a signed type, this is
bound to cause a warning.
Please move the "n" variable below to the top of this function and use
that as an index variable here too.

> + page = vmalloc_to_page((void *)(start + PAGE_SIZE * i));
> + if (!page)
> + return -ENOMEM;
> +
> + get_page(page);
> + pages[i] = page;
> + }
> + rc = page_count;
> + } else {
> + struct kvec *kiov;
> + size_t n;
> +
> + kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL);
> + if (!kiov)
> + return -ENOMEM;
> +
> + for (n = 0; n < page_count; n++) {
> + kiov[n].iov_base = (void *)(start + n * PAGE_SIZE);
> + kiov[n].iov_len = PAGE_SIZE;
> + }
> +
> + rc = get_kernel_pages(kiov, page_count, 0, pages);
> + kfree(kiov);
> }
>
> - rc = get_kernel_pages(kiov, page_count, 0, pages);
> - kfree(kiov);
> -
> return rc;
> }
>
> --
> 2.25.1

This patch makes sense. Please fix the comment above and post a v3
(with a changelog this time).

Cheers,
Jens

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