[PATCH 1/2] device: Stop requiring that struct device is embedded in struct pci_dev

[Bart Van Assche]

The dma mapping operations of several architectures and also of
several I/O MMU implementations need to translate a struct
device pointer into a struct pci_dev pointer. This translation
is performed by to_pci_dev(). That macro assumes that struct
device is embedded in struct pci_dev. However, that is not the
case for the device structure in struct ib_device. Since that
device structure is passed to DMA mapping operations since kernel
v4.11-rc1, introduce a pointer in struct device to make the
translation from struct device into struct pci_dev more flexible.

Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
---
 drivers/pci/probe.c    | 1 +
 include/linux/device.h | 5 +++++
 include/linux/pci.h    | 5 ++++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index dfc9a2794141..60d739b59520 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1736,6 +1736,7 @@ struct pci_dev *pci_alloc_dev(struct pci_bus *bus)
 
 	INIT_LIST_HEAD(&dev->bus_list);
 	dev->dev.type = &pci_dev_type;
+	dev->dev.pci_dev = dev;
 	dev->bus = pci_bus_get(bus);
 
 	return dev;
diff --git a/include/linux/device.h b/include/linux/device.h
index 30c4570e928d..c18afd376d2a 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -42,6 +42,7 @@ struct fwnode_handle;
 struct iommu_ops;
 struct iommu_group;
 struct iommu_fwspec;
+struct pci_dev;
 
 struct bus_attribute {
 	struct attribute	attr;
@@ -860,6 +861,9 @@ struct dev_links_info {
  * 		segment limitations.
  * @dma_pools:	Dma pools (if dma'ble device).
  * @dma_mem:	Internal for coherent mem override.
+ * @pci_dev:	PCI device associated with this device. Used by DMA mapping
+ *		operations on architectures that need access to PCI device
+ *		members that are not in struct device.
  * @cma_area:	Contiguous memory area for dma allocations
  * @archdata:	For arch-specific additions.
  * @of_node:	Associated device tree node.
@@ -940,6 +944,7 @@ struct device {
 
 	struct dma_coherent_mem	*dma_mem; /* internal for coherent mem
 					     override */
+	struct pci_dev		*pci_dev; /* for DMA mapping operations */
 #ifdef CONFIG_DMA_CMA
 	struct cma *cma_area;		/* contiguous memory area for dma
 					   allocations */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index eb3da1a04e6c..eca790eaae20 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -409,7 +409,10 @@ static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
 
 struct pci_dev *pci_alloc_dev(struct pci_bus *bus);
 
-#define	to_pci_dev(n) container_of(n, struct pci_dev, dev)
+static inline struct pci_dev *to_pci_dev(const struct device *dev)
+{
+	return dev->pci_dev;
+}
 #define for_each_pci_dev(d) while ((d = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, d)) != NULL)
 
 static inline int pci_channel_offline(struct pci_dev *pdev)
-- 
2.12.0