Merge tag 'dma-mapping-4.18' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - replace the force_dma flag with a dma_configure bus method. (Nipun
   Gupta, although one patch is іncorrectly attributed to me due to a
   git rebase bug)

 - use GFP_DMA32 more agressively in dma-direct. (Takashi Iwai)

 - remove PCI_DMA_BUS_IS_PHYS and rely on the dma-mapping API to do the
   right thing for bounce buffering.

 - move dma-debug initialization to common code, and apply a few
   cleanups to the dma-debug code.

 - cleanup the Kconfig mess around swiotlb selection

 - swiotlb comment fixup (Yisheng Xie)

 - a trivial swiotlb fix. (Dan Carpenter)

 - support swiotlb on RISC-V. (based on a patch from Palmer Dabbelt)

 - add a new generic dma-noncoherent dma_map_ops implementation and use
   it for arc, c6x and nds32.

 - improve scatterlist validity checking in dma-debug. (Robin Murphy)

 - add a struct device quirk to limit the dma-mask to 32-bit due to
   bridge/system issues, and switch x86 to use it instead of a local
   hack for VIA bridges.

 - handle devices without a dma_mask more gracefully in the dma-direct
   code.

* tag 'dma-mapping-4.18' of git://git.infradead.org/users/hch/dma-mapping: (48 commits)
  dma-direct: don't crash on device without dma_mask
  nds32: use generic dma_noncoherent_ops
  nds32: implement the unmap_sg DMA operation
  nds32: consolidate DMA cache maintainance routines
  x86/pci-dma: switch the VIA 32-bit DMA quirk to use the struct device flag
  x86/pci-dma: remove the explicit nodac and allowdac option
  x86/pci-dma: remove the experimental forcesac boot option
  Documentation/x86: remove a stray reference to pci-nommu.c
  core, dma-direct: add a flag 32-bit dma limits
  dma-mapping: remove unused gfp_t parameter to arch_dma_alloc_attrs
  dma-debug: check scatterlist segments
  c6x: use generic dma_noncoherent_ops
  arc: use generic dma_noncoherent_ops
  arc: fix arc_dma_{map,unmap}_page
  arc: fix arc_dma_sync_sg_for_{cpu,device}
  arc: simplify arc_dma_sync_single_for_{cpu,device}
  dma-mapping: provide a generic dma-noncoherent implementation
  dma-mapping: simplify Kconfig dependencies
  riscv: add swiotlb support
  riscv: only enable ZONE_DMA32 for 64-bit
  ...

1 files changed, 1 insertions, 19 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 2af787e8b130..983b277a1229 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2884,11 +2884,7 @@ void netdev_rx_csum_fault(struct net_device *dev)
 EXPORT_SYMBOL(netdev_rx_csum_fault);
 #endif
 
-/* Actually, we should eliminate this check as soon as we know, that:
- * 1. IOMMU is present and allows to map all the memory.
- * 2. No high memory really exists on this machine.
- */
-
+/* XXX: check that highmem exists at all on the given machine. */
 static int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 {
 #ifdef CONFIG_HIGHMEM
@@ -2902,20 +2898,6 @@ static int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 				return 1;
 		}
 	}
-
-	if (PCI_DMA_BUS_IS_PHYS) {
-		struct device *pdev = dev->dev.parent;
-
-		if (!pdev)
-			return 0;
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
-			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
-			dma_addr_t addr = page_to_phys(skb_frag_page(frag));
-
-			if (!pdev->dma_mask || addr + PAGE_SIZE - 1 > *pdev->dma_mask)
-				return 1;
-		}
-	}
 #endif
 	return 0;
 }