[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] xen/gntdev: add ioctl for grant copy
On 13/01/16 19:56, Dan Carpenter wrote: > 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? This is non-zero if XEN_PAGE_SIZE < PAGE_SIZE and is needed for this case. David _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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