On Wed, Sep 04, 2019 at 01:47:31PM +0530, Nagarjuna Kristam wrote:
> In usbfs mmap, usb_alloc_coherent is used to allocate memory.
> This Memory is then remapped to user space memory using remap_pfn_range.
> remap_pfn_range needs phy address of memory, for which virt_to_phy API
> is used. This API works only if memory is allocated using kmalloc. But
> usb_alloc_coherent can allocate memory in vmalloc range and this causes
> wrong remap of user memory.
>
> Check if address returned by usb_alloc_coherent failed in vmalloc range
> and if yes, use remap_vmalloc_range API, else use remap_pfn_range to remap
> address to user space.
>
> Signed-off-by: Nagarjuna Kristam <nkristam@xxxxxxxxxx>
> ---
> drivers/usb/core/devio.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
> index a945ad7..20999de 100644
> --- a/drivers/usb/core/devio.c
> +++ b/drivers/usb/core/devio.c
> @@ -250,7 +250,12 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
> usbm->vma_use_count = 1;
> INIT_LIST_HEAD(&usbm->memlist);
>
> - if (remap_pfn_range(vma, vma->vm_start,
> + if (is_vmalloc_addr(usbm->mem)) {
> + if (remap_vmalloc_range(vma, usbm->mem, 0) < 0) {
> + dec_usb_memory_use_count(usbm, &usbm->vma_use_count);
> + return -EAGAIN;
> + }
> + } else if (remap_pfn_range(vma, vma->vm_start,
> virt_to_phys(usbm->mem) >> PAGE_SHIFT,
> size, vma->vm_page_prot) < 0) {
> dec_usb_memory_use_count(usbm, &usbm->vma_use_count);
> --
> 2.7.4
>
With the recent dma changes, is this patch still needed and correct?
thanks,
greg k-h
