iommu sg merging: PCI: add dma segment boundary support

This adds PCI's accessor for segment_boundary_mask in device_dma_parameters.

The default segment_boundary is set to 0xffffffff, same to the block layer's
default value (and the scsi mid layer uses the same value).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/pci/pci.c

@@ -1459,6 +1459,14 @@ int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size)
 EXPORT_SYMBOL(pci_set_dma_max_seg_size);
 #endif
 
+#ifndef HAVE_ARCH_PCI_SET_DMA_SEGMENT_BOUNDARY
+int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask)
+{
+	return dma_set_seg_boundary(&dev->dev, mask);
+}
+EXPORT_SYMBOL(pci_set_dma_seg_boundary);
+#endif
+
 /**
  * pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count
  * @dev: PCI device to query

drivers/pci/probe.c

@@ -937,6 +937,7 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	dev->dev.coherent_dma_mask = 0xffffffffull;
 
 	pci_set_dma_max_seg_size(dev, 65536);
+	pci_set_dma_seg_boundary(dev, 0xffffffff);
 
 	/* Fix up broken headers */
 	pci_fixup_device(pci_fixup_header, dev);

include/linux/pci.h

@@ -583,6 +583,7 @@ void pci_msi_off(struct pci_dev *dev);
 int pci_set_dma_mask(struct pci_dev *dev, u64 mask);
 int pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask);
 int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size);
+int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask);
 int pcix_get_max_mmrbc(struct pci_dev *dev);
 int pcix_get_mmrbc(struct pci_dev *dev);
 int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc);
@@ -831,6 +832,12 @@ static inline int pci_set_dma_max_seg_size(struct pci_dev *dev,
 	return -EIO;
 }
 
+static inline int pci_set_dma_seg_boundary(struct pci_dev *dev,
+					unsigned long mask)
+{
+	return -EIO;
+}
+
 static inline int pci_assign_resource(struct pci_dev *dev, int i)
 {
 	return -EBUSY;