[PATCH 2/6] iommu/io-pgtable: Allow a pgtable implementation to skip TLB operations

[Jordan Crouse <jcrouse@codeaurora.org>]

Allow a io-pgtable implementation to skip TLB operations by checking for
NULL pointers in the helper functions. It will be up to to the owner
of the io-pgtable instance to make sure that they independently handle
the TLB correctly.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---

 include/linux/io-pgtable.h | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index 53d53c6c2be9..bbed1d3925ba 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -210,21 +210,24 @@ struct io_pgtable {
 
 static inline void io_pgtable_tlb_flush_all(struct io_pgtable *iop)
 {
-	iop->cfg.tlb->tlb_flush_all(iop->cookie);
+	if (iop->cfg.tlb)
+		iop->cfg.tlb->tlb_flush_all(iop->cookie);
 }
 
 static inline void
 io_pgtable_tlb_flush_walk(struct io_pgtable *iop, unsigned long iova,
 			  size_t size, size_t granule)
 {
-	iop->cfg.tlb->tlb_flush_walk(iova, size, granule, iop->cookie);
+	if (iop->cfg.tlb)
+		iop->cfg.tlb->tlb_flush_walk(iova, size, granule, iop->cookie);
 }
 
 static inline void
 io_pgtable_tlb_flush_leaf(struct io_pgtable *iop, unsigned long iova,
 			  size_t size, size_t granule)
 {
-	iop->cfg.tlb->tlb_flush_leaf(iova, size, granule, iop->cookie);
+	if (iop->cfg.tlb)
+		iop->cfg.tlb->tlb_flush_leaf(iova, size, granule, iop->cookie);
 }
 
 static inline void
@@ -232,7 +235,7 @@ io_pgtable_tlb_add_page(struct io_pgtable *iop,
 			struct iommu_iotlb_gather * gather, unsigned long iova,
 			size_t granule)
 {
-	if (iop->cfg.tlb->tlb_add_page)
+	if (iop->cfg.tlb && iop->cfg.tlb->tlb_add_page)
 		iop->cfg.tlb->tlb_add_page(gather, iova, granule, iop->cookie);
 }
 
-- 
2.17.1