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Commit c6bfaeb5 authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Bjorn Helgaas
Browse files

PCI/P2PDMA: Factor out __upstream_bridge_distance() 

This is a prep patch to create a second level helper. There are no
functional changes.

The root complex whitelist code will be moved into this function in a
subsequent patch.

Link: https://lore.kernel.org/r/20190730163545.4915-5-logang@deltatee.com
Link: https://lore.kernel.org/r/20190812173048.9186-5-logang@deltatee.com


Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 72583084

drivers/pci/p2pdma.c

+48 −40
Original line number Diff line number Diff line
@@ -296,47 +296,8 @@ static bool root_complex_whitelist(struct pci_dev *dev) 
	return false;

}



/*

 * Find the distance through the nearest common upstream bridge between

 * two PCI devices.

 *

 * If the two devices are the same device then 0 will be returned.

 *

 * If there are two virtual functions of the same device behind the same

 * bridge port then 2 will be returned (one step down to the PCIe switch,

 * then one step back to the same device).

 *

 * In the case where two devices are connected to the same PCIe switch, the

 * value 4 will be returned. This corresponds to the following PCI tree:

 *

 *     -+  Root Port

 *      \+ Switch Upstream Port

 *       +-+ Switch Downstream Port

 *       + \- Device A

 *       \-+ Switch Downstream Port

 *         \- Device B

 *

 * The distance is 4 because we traverse from Device A through the downstream

 * port of the switch, to the common upstream port, back up to the second

 * downstream port and then to Device B.

 *

 * Any two devices that cannot communicate using p2pdma will return

 * PCI_P2PDMA_MAP_NOT_SUPPORTED.

 *

 * Any two devices that have a data path that goes through the host bridge

 * will consult a whitelist. If the host bridges are on the whitelist,

 * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE.

 *

 * If either bridge is not on the whitelist this function returns

 * PCI_P2PDMA_MAP_NOT_SUPPORTED.

 *

 * If a bridge which has any ACS redirection bits set is in the path,

 * acs_redirects will be set to true. In this case, a list of all infringing

 * bridge addresses will be populated in acs_list (assuming it's non-null)

 * for printk purposes.

 */

static enum pci_p2pdma_map_type

upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,

__upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,

		int *dist, bool *acs_redirects, struct seq_buf *acs_list)

{

	struct pci_dev *a = provider, *b = client, *bb;
@@ -416,6 +377,53 @@ upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, 
	return PCI_P2PDMA_MAP_BUS_ADDR;

}



/*

 * Find the distance through the nearest common upstream bridge between

 * two PCI devices.

 *

 * If the two devices are the same device then 0 will be returned.

 *

 * If there are two virtual functions of the same device behind the same

 * bridge port then 2 will be returned (one step down to the PCIe switch,

 * then one step back to the same device).

 *

 * In the case where two devices are connected to the same PCIe switch, the

 * value 4 will be returned. This corresponds to the following PCI tree:

 *

 *     -+  Root Port

 *      \+ Switch Upstream Port

 *       +-+ Switch Downstream Port

 *       + \- Device A

 *       \-+ Switch Downstream Port

 *         \- Device B

 *

 * The distance is 4 because we traverse from Device A through the downstream

 * port of the switch, to the common upstream port, back up to the second

 * downstream port and then to Device B.

 *

 * Any two devices that cannot communicate using p2pdma will return

 * PCI_P2PDMA_MAP_NOT_SUPPORTED.

 *

 * Any two devices that have a data path that goes through the host bridge

 * will consult a whitelist. If the host bridges are on the whitelist,

 * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE.

 *

 * If either bridge is not on the whitelist this function returns

 * PCI_P2PDMA_MAP_NOT_SUPPORTED.

 *

 * If a bridge which has any ACS redirection bits set is in the path,

 * acs_redirects will be set to true. In this case, a list of all infringing

 * bridge addresses will be populated in acs_list (assuming it's non-null)

 * for printk purposes.

 */

static enum pci_p2pdma_map_type

upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,

		int *dist, bool *acs_redirects, struct seq_buf *acs_list)

{

	return __upstream_bridge_distance(provider, client, dist,

					  acs_redirects, acs_list);

}



static enum pci_p2pdma_map_type

upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client,

			      int *dist)