PCI/P2PDMA: Gate the host bridge whitelist warning on verbose

calc_map_type_and_dist() prints every other diagnostic under its verbose
argument, but reaches the "Host bridge not in P2PDMA whitelist" warning
through host_bridge_whitelist(), which it hands acs_redirects instead.  A
caller that asked for a silent answer still gets the warning whenever any
port on the path has an ACS redirect bit set, the CPU is not whitelisted by
cpu_supports_p2pdma(), and the host bridge is not in
pci_p2pdma_whitelist[].

pci_p2pmem_find_many() is such a caller. It sweeps every device with
published p2pmem and asks for the distance to each client with
verbose=false, and pci_p2pdma_distance_many() recomputes rather than
consulting the map_types cache, so the warning repeats on every sweep.

The argument was never meant to say "ACS redirects were found". When commit
cf201bfe8cdc ("PCI/P2PDMA: Warn if host bridge not in whitelist") added it,
acs_redirects was a bool pointer that the quiet entry point passed as NULL:

  if (verbose)
	  map = calc_map_type_and_dist_warn(provider, pci_client,
					    &distance);
  else
	  map = calc_map_type_and_dist(provider, pci_client,
				       &distance, NULL, NULL);

so the argument was true on exactly the path that commit describes.
Folding the two entry points into one verbose flag turned the pointer into
a value and left the call site alone, silently narrowing the warning to
paths that carry an ACS redirect.

Pass verbose. This also restores the warning for a verbose caller that
takes the host bridge route with no ACS redirect on the path, which until
now was told it could not use peer-to-peer DMA without being told which
vendor and device would have to be added to the whitelist.

Fixes: d1b8dc09dd71 ("PCI/P2PDMA: Simplify distance calculation")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Tushar Dave <tdave@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Link: https://patch.msgid.link/20260830-batch-p2p-fixes-v1-5-5044e8dfbe2e@nvidia.com

0 files changed, 0 insertions, 0 deletions