[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] xen/gntdev: add ioctl for grant copy
Hello David Vrabel, The patch a4cdb556cae0: "xen/gntdev: add ioctl for grant copy" from Dec 2, 2014, leads to the following static checker warning: drivers/xen/gntdev.c:775 gntdev_get_page() warn: mask and shift to zero drivers/xen/gntdev.c 761 static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, 762 bool writeable, unsigned long *gfn) 763 { 764 unsigned long addr = (unsigned long)virt; 765 struct page *page; 766 unsigned long xen_pfn; 767 int ret; 768 769 ret = get_user_pages_fast(addr, 1, writeable, &page); 770 if (ret < 0) 771 return ret; 772 773 batch->pages[batch->nr_pages++] = page; 774 775 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This is zero most of the time. Did you intend the bitwise negate? 776 *gfn = pfn_to_gfn(xen_pfn); 777 778 return 0; 779 } regards, dan carpenter _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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