Re: [PATCH v8 5/9] PCI: Add pci_iomap_wc() variants

On Thu, Jun 25, 2015 at 8:09 AM, Borislav Petkov [off-list ref] wrote:

quoted

+void __iomem *pci_iomap_wc_range(struct pci_dev *dev,
+                              int bar,
+                              unsigned long offset,
+                              unsigned long maxlen)
+{
+     resource_size_t start = pci_resource_start(dev, bar);
+     resource_size_t len = pci_resource_len(dev, bar);
+     unsigned long flags = pci_resource_flags(dev, bar);
+
+     if (len <= offset || !start)
+             return NULL;
+     len -= offset;
+     start += offset;
+     if (maxlen && len > maxlen)
+             len = maxlen;
+     if (flags & IORESOURCE_IO)
+             return NULL;

I've moved this check at the beginning of the function so that we bail
out before doing the computations above it.

That indeed looks like a good optimization.

 Luis