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PCI: Protect pci_reassign_bridge_resources() against concurrent addition/removal 

pci_reassign_bridge_resources() can be called by pci_resize_resource() at
runtime, it walks the PCI tree up and down, and it isn't currently
protected against any changes or hotplug operation.

Hold the pci_bus_sem to protect it.

Link: https://lore.kernel.org/r/7339fd73ccaf58552737ab10008333fd9f7723f2.camel@kernel.crashing.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Benjamin Herrenschmidt 2019-09-25 11:16:55 +10:00 committed by Bjorn Helgaas
parent 54ecb8f702
commit fb794a708a
1 changed files with 7 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/pci/setup-bus.c
View File

@ -2066,6 +2066,8 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
unsigned int i;
int ret;
down_read(&pci_bus_sem);
/* Walk to the root hub, releasing bridge BARs when possible */
next = bridge;
do {
@ -2100,8 +2102,10 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
next = bridge->bus ? bridge->bus->self : NULL;
} while (next);
if (list_empty(&saved))
if (list_empty(&saved)) {
up_read(&pci_bus_sem);
return -ENOENT;
}
__pci_bus_size_bridges(bridge->subordinate, &added);
__pci_bridge_assign_resources(bridge, &added, &failed);
@ -2122,6 +2126,7 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
}
free_list(&saved);
up_read(&pci_bus_sem);
return 0;
cleanup:
@ -2150,6 +2155,7 @@ cleanup:
pci_setup_bridge(bridge->subordinate);
}
free_list(&saved);
up_read(&pci_bus_sem);
return ret;
}