Hi, All, If my understanding were correct, device_lock is used to provide mutual exclusion between device probe/remove/suspend/resume etc. Why hold device_lock when calling callback in pci_walk_bus.
This is introduced by the following commit. commit d71374dafbba7ec3f67371d3b7e9f6310a588808 Author: Zhang Yanmin <[email protected]> Date: Fri Jun 2 12:35:43 2006 +0800 [PATCH] PCI: fix race with pci_walk_bus and pci_destroy_dev pci_walk_bus has a race with pci_destroy_dev. When cb is called in pci_walk_bus, pci_destroy_dev might unlink the dev pointed by next. Later on in the next loop, pointer next becomes NULL and cause kernel panic. Below patch against 2.6.17-rc4 fixes it by changing pci_bus_lock (spin_lock) to pci_bus_sem (rw_semaphore). Signed-off-by: Zhang Yanmin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Corresponding email thread is: https://lkml.org/lkml/2006/5/26/38 But from the commit and email thread, I can not find why we need to do that. I ask this question because I want to use pci_walk_bus in a function (in pci runtime resume path) which may be called with device_lock held. Can anyone help me on that? Best Regards, Huang Ying -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
