On 2020-06-26 21:04, Jordan Crouse wrote:
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.
I don't really understand what this is for - tricking the IOMMU driver into not performing its TLB maintenance at points when that maintenance has been deemed necessary doesn't seem like the appropriate way to achieve anything good :/
Robin.
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 voidio_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 voidio_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); }
