[PATCH v2 2/6] iommu/io-pgtable: Allow a pgtable implementation to skip TLB operations

From: Jordan Crouse
Date: Fri Jun 26 2020 - 16:04:56 EST


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@xxxxxxxxxxxxxx>
---

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