| Message ID | 4d439f68d1f746d94215971891e0ed74fd1b2776.1476875113.git.lukas@wunner.de (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index ba34907..6e0c399 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2292,7 +2292,6 @@ static void pci_bridge_d3_update(struct pci_dev *dev, bool remove) if (!bridge || !pci_bridge_d3_possible(bridge)) return; - pci_dev_get(bridge); /* * If the device is removed we do not care about its D3cold * capabilities. @@ -2314,8 +2313,6 @@ static void pci_bridge_d3_update(struct pci_dev *dev, bool remove) /* Propagate change to upstream bridges */ pci_bridge_d3_update(bridge, false); } - - pci_dev_put(bridge); } /**
This function is always called with an existing pci_dev struct, which holds a reference on the pci_bus struct it resides on, which in turn holds a reference on pci_bus->bridge, which is the pci_dev's parent. Hence there's no need to acquire an additional ref on the parent. More specifically, the pci_dev exists until pci_destroy_dev() drops the final reference on it, so all calls to pci_bridge_d3_update() must be finished before that. It is arguably the caller's responsibility to ensure that it doesn't call pci_bridge_d3_update() with a pci_dev that might suddenly disappear, but in any case the existing callers are all safe: - The call in pci_destroy_dev() happens before the call to put_device(). - The call in pci_bus_add_device() is synchronized with pci_destroy_dev() using pci_lock_rescan_remove(). - The calls to pci_d3cold_disable() from the xhci and nouveau drivers are safe because a ref on the pci_dev is held as long as it's bound to a driver. - The calls to pci_d3cold_enable() / pci_d3cold_disable() when modifying the sysfs "d3cold_allowed" entry are also safe because kernfs_drain() waits for existing sysfs users to finish before removing the entry, and pci_destroy_dev() is called way after that. No functional change intended. Cc: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> --- drivers/pci/pci.c | 3 --- 1 file changed, 3 deletions(-)