Messages in this thread | | | Subject | Re: [PATCH] swiotlb-xen: override common mmap and get_sgtable dma ops | From | Boris Ostrovsky <> | Date | Fri, 11 Jun 2021 11:19:58 -0400 |
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On 6/11/21 5:55 AM, Roman Skakun wrote: > > +static int > +xen_swiotlb_dma_mmap(struct device *dev, struct vm_area_struct *vma, > + void *cpu_addr, dma_addr_t dma_addr, size_t size, > + unsigned long attrs) > +{ > + unsigned long user_count = vma_pages(vma); > + unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; > + unsigned long off = vma->vm_pgoff; > + struct page *page; > + > + if (is_vmalloc_addr(cpu_addr)) > + page = vmalloc_to_page(cpu_addr); > + else > + page = virt_to_page(cpu_addr); > + > + vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); > + > + if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) > + return -ENXIO; > + > + if (off >= count || user_count > count - off) > + return -ENXIO; > + > + return remap_pfn_range(vma, vma->vm_start, > + page_to_pfn(page) + vma->vm_pgoff, > + user_count << PAGE_SHIFT, vma->vm_page_prot); > +}
I suggest you create a helper for computing page value and then revert 922659ea771b3fd728149262c5ea15608fab9719 and pass result of the helper instead of cpu_addr. Here and in xen_swiotlb_dma_get_sgtable().
And use this new helper in xen_swiotlb_free_coherent() too. I am curious though why this was not a problem when Stefano was looking at the problem that introduced this vmalloc check (i.e. 8b1e868f66076490189a36d984fcce286cdd6295). Stefano?
-boris
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