Hello Dan,
> -----Original Message----->
> Hello Wei Hu,
>
> The patch 3a6fb6c4255c: "video: hyperv: hyperv_fb: Use physical memory for
> fb on HyperV Gen 1 VMs." from Dec 9, 2019, leads to the following static
> checker warning:
>
> drivers/video/fbdev/hyperv_fb.c:991 hvfb_get_phymem()
> error: 'vmem' came from dma_alloc_coherent() so we can't do
> virt_to_phys()
>
> drivers/video/fbdev/hyperv_fb.c
> 960 static phys_addr_t hvfb_get_phymem(struct hv_device *hdev,
> 961 unsigned int request_size)
> 962 {
> 963 struct page *page = NULL;
> 964 dma_addr_t dma_handle;
> 965 void *vmem;
> 966 phys_addr_t paddr = 0;
> 967 unsigned int order = get_order(request_size);
> 968
> 969 if (request_size == 0)
> 970 return -1;
> 971
> 972 if (order < MAX_ORDER) {
> 973 /* Call alloc_pages if the size is less than 2^MAX_ORDER */
> 974 page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
> 975 if (!page)
> 976 return -1;
> 977
> 978 paddr = (page_to_pfn(page) << PAGE_SHIFT);
> 979 } else {
> 980 /* Allocate from CMA */
> 981 hdev->device.coherent_dma_mask = DMA_BIT_MASK(64);
> 982
> 983 vmem = dma_alloc_coherent(&hdev->device,
> 984 round_up(request_size, PAGE_SIZE),
> 985 &dma_handle,
> 986 GFP_KERNEL | __GFP_NOWARN);
> 987
> 988 if (!vmem)
> 989 return -1;
> 990
> 991 paddr = virt_to_phys(vmem);
>
> Pretty straight forward that the static checker is right but I can't give you any
> hints how to fix it.
>
Thanks for reporting this. Would you let me know how I can reproduce this warning or
Error message? The build on my side runs fine without such message.
Thanks,
Wei
