On Mon, Oct 08, 2018 at 10:02:39AM +0200, Christoph Hellwig wrote: > All properly written drivers now have error handling in the > dma_map_single / dma_map_page callers. As swiotlb_tbl_map_single already > prints a useful warning when running out of swiotlb pool swace we can
s/swace/space/ > also remove swiotlb_full entirely as it serves no purpose now. The panic albeit was useful for those drivers that didn't handle it. Thoughts? I am kind of thinking screw them but then I am not too thrilled about silent data corruption errors. > > Signed-off-by: Christoph Hellwig <[email protected]> > --- > kernel/dma/swiotlb.c | 33 +-------------------------------- > 1 file changed, 1 insertion(+), 32 deletions(-) > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index 26d3af52956f..69bf305ee5f8 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -761,34 +761,6 @@ static bool swiotlb_free_buffer(struct device *dev, > size_t size, > return true; > } > > -static void > -swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir, > - int do_panic) > -{ > - if (swiotlb_force == SWIOTLB_NO_FORCE) > - return; > - > - /* > - * Ran out of IOMMU space for this operation. This is very bad. > - * Unfortunately the drivers cannot handle this operation properly. > - * unless they check for dma_mapping_error (most don't) > - * When the mapping is small enough return a static buffer to limit > - * the damage, or panic when the transfer is too big. > - */ > - dev_err_ratelimited(dev, "DMA: Out of SW-IOMMU space for %zu bytes\n", > - size); > - > - if (size <= io_tlb_overflow || !do_panic) > - return; > - > - if (dir == DMA_BIDIRECTIONAL) > - panic("DMA: Random memory could be DMA accessed\n"); > - if (dir == DMA_FROM_DEVICE) > - panic("DMA: Random memory could be DMA written\n"); > - if (dir == DMA_TO_DEVICE) > - panic("DMA: Random memory could be DMA read\n"); > -} > - > /* > * Map a single buffer of the indicated size for DMA in streaming mode. The > * physical address to use is returned. > @@ -817,10 +789,8 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct > page *page, > > /* Oh well, have to allocate and map a bounce buffer. */ > map = map_single(dev, phys, size, dir, attrs); > - if (map == SWIOTLB_MAP_ERROR) { > - swiotlb_full(dev, size, dir, 1); > + if (map == SWIOTLB_MAP_ERROR) > return __phys_to_dma(dev, io_tlb_overflow_buffer); > - } > > dev_addr = __phys_to_dma(dev, map); > > @@ -948,7 +918,6 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct > scatterlist *sgl, int nelems, > if (map == SWIOTLB_MAP_ERROR) { > /* Don't panic here, we expect map_sg users > to do proper error handling. */ > - swiotlb_full(hwdev, sg->length, dir, 0); > attrs |= DMA_ATTR_SKIP_CPU_SYNC; > swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, > attrs); > -- > 2.19.0 > _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
