On Tue, 2014-07-29 at 15:04 +0100, Edward Cree wrote: > Not sure if this list is the right place to ask, but: > I'm working on fallback code in the sfc driver where in some > configurations the device won't support using VFs, but will still > advertise them as present [1]. This is discovered at PF probe time, and > what I want to do is just set sriov_totalvfs to 0 in this case. > > As far as I can tell, pci_sriov_set_totalvfs (drivers/pci/iov.c) is the > function to call, but I'm confused by the comment on that function which > states "Should be called from PF driver's probe routine with device's > mutex held." > > Specifically, it's unclear what mutex is meant. struct pci_dev doesn't > have one; struct pci_sriov /does/ but the struct is only defined in > drivers/pci/pci.h which I don't appear to be able to include from a > driver. There's also one in the 'struct device dev' member of struct > pci_dev, but that seems rather unlikely. > > Also, the wording of the comment makes me wonder if being in the PF > probe routine /implies/ that the mutex is held already, in which case I > don't have to do anything. This is supported by the only callers, > igb_probe (via igb_sw_init and igb_probe_vfs) and ixgbe_probe, not > appearing to take any mutexes before calling pci_sriov_set_totalvfs. I believe this is referring to device_lock(), which should already be held on the PF during probe. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
