Re: [PATCH v1] x86/mm, asm-generic: Add IOMMU ioremap_uc() variant default

On Thu, Mar 16, 2017 at 03:46:51PM -0500, Bjorn Helgaas wrote:

On Thu, Jul 9, 2015 at 7:28 PM, Luis R. Rodriguez
[off-list ref] wrote:

quoted

+/**
+ * DOC: ioremap() and ioremap_*() variants
+ *
+ * If you have an IOMMU your architecture is expected to have both ioremap()
+ * and iounmap() implemented otherwise the asm-generic helpers will provide a
+ * direct mapping.
+ *
+ * There are ioremap_*() call variants, if you have no IOMMU we naturally will
+ * default to direct mapping for all of them, you can override these defaults.
+ * If you have an IOMMU you are highly encouraged to provide your own
+ * ioremap variant implementation as there currently is no safe architecture
+ * agnostic default. To avoid possible improper behaviour default asm-generic
+ * ioremap_*() variants all return NULL when an IOMMU is available. If you've
+ * defined your own ioremap_*() variant you must then declare your own
+ * ioremap_*() variant as defined to itself to avoid the default NULL return.

Are the references above to "IOMMU" typos?  Should they say "MMU"
instead, so they match the #ifdef below?

Yes. Patch welcomed.

  Luis