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PCI/P2PDMA: Update pci_p2pdma_distance_many() documentation

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The comment describing pci_p2pdma_distance_many() still referred to
the devices being behind the same root port. This no longer applies
so reword the documentation.

Link: https://lore.kernel.org/r/20190730163545.4915-15-logang@deltatee.com
Link: https://lore.kernel.org/r/20190812173048.9186-15-logang@deltatee.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Logan Gunthorpe 2019-08-12 11:30:48 -06:00 committed by Bjorn Helgaas
parent 5daf40b039
commit 27235b15e4
1 changed files with 7 additions and 8 deletions
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15
drivers/pci/p2pdma.c
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@ -517,15 +517,14 @@ upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client,
* @num_clients: number of clients in the array
* @verbose: if true, print warnings for devices when we return -1
*
* Returns -1 if any of the clients are not compatible (behind the same
* root port as the provider), otherwise returns a positive number where
* a lower number is the preferable choice. (If there's one client
* that's the same as the provider it will return 0, which is best choice).
* Returns -1 if any of the clients are not compatible, otherwise returns a
* positive number where a lower number is the preferable choice. (If there's
* one client that's the same as the provider it will return 0, which is best
* choice).
*
* For now, "compatible" means the provider and the clients are all behind
* the same PCI root port. This cuts out cases that may work but is safest
* for the user. Future work can expand this to white-list root complexes that
* can safely forward between each ports.
* "compatible" means the provider and the clients are either all behind
* the same PCI root port or the host bridges connected to each of the devices
* are listed in the 'pci_p2pdma_whitelist'.
*/
int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients,
int num_clients, bool verbose)