Allow cacheable mmaps of legacy_mem if WB access is supported for the region.
The "legacy_mem" file often contains a shadow option ROM, and some versions of
X depend on this.
Tim Yamin <plasm@roo.me.uk> reported that this change fixes X on a Dell
PowerEdge 3250.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
                return -EINVAL;
        prot = phys_mem_access_prot(NULL, vma->vm_pgoff, size,
                                    vma->vm_page_prot);
-       if (pgprot_val(prot) != pgprot_val(pgprot_noncached(vma->vm_page_prot)))
-               return -EINVAL;
 
        addr = pci_get_legacy_mem(bus);
        if (IS_ERR(addr))