Hello Benjamin Herrenschmidt,
The patch 540f62d26f02: "PCI: Protect pci_reassign_bridge_resources()
against addition/removal" from Jun 24, 2019, leads to the following
static checker warning:
drivers/pci/setup-bus.c:2158 pci_reassign_bridge_resources()
warn: inconsistent returns 'read_sem:&pci_bus_sem'.
drivers/pci/setup-bus.c
2066 unsigned int i;
2067 int ret;
2068
2069 down_read(&pci_bus_sem);
We added some new locking here.
2070
2071 /* Walk to the root hub, releasing bridge BARs when possible */
2072 next = bridge;
2073 do {
2074 bridge = next;
2075 for (i = PCI_BRIDGE_RESOURCES; i < PCI_BRIDGE_RESOURCE_END;
2076 i++) {
2077 struct resource *res = &bridge->resource[i];
2078
2079 if ((res->flags ^ type) & PCI_RES_TYPE_MASK)
2080 continue;
2081
2082 /* Ignore BARs which are still in use */
2083 if (res->child)
2084 continue;
2085
2086 ret = add_to_list(&saved, bridge, res, 0, 0);
2087 if (ret)
2088 goto cleanup;
2089
2090 pci_info(bridge, "BAR %d: releasing %pR\n",
2091 i, res);
2092
2093 if (res->parent)
2094 release_resource(res);
2095 res->start = 0;
2096 res->end = 0;
2097 break;
2098 }
2099 if (i == PCI_BRIDGE_RESOURCE_END)
2100 break;
2101
2102 next = bridge->bus ? bridge->bus->self : NULL;
2103 } while (next);
2104
2105 if (list_empty(&saved))
2106 return -ENOENT;
This needs an unlock. It's not clear to me if any other clean up is
required, but possibly it's worth looking at.
2107
2108 __pci_bus_size_bridges(bridge->subordinate, &added);
2109 __pci_bridge_assign_resources(bridge, &added, &failed);
regards,
dan carpenter
