On Wed, Apr 06, 2011 at 11:16:07AM -0400, Alan Stern wrote: > On Wed, 6 Apr 2011, Joerg Roedel wrote: > The counter really should be a bool: Has the chipset already been > probed or not? After all, nobody cares how many times this routine was > called. > > > + spin_unlock_irqrestore(&amd_lock, flags); > > This code now contains a bug: You incremented the probe_count _before_ > doing the probe. If another thread calls this routine right now, it > will get an incorrect result. > > Fixing this up should be fairly easy. Hmm, we can get rid of the amd_lock completly if every thread uses the following call-order: usb_amd_find_chipset_info(); usb_amd_quirk_pll_enable(); usb_amd_quirk_pll_disable(); usb_amd_dev_put(); In that case we can just change the probe_count and isoc_reqs into atomic_t with some care and should be fine, no? Problem is that I don't know if the above call-order is guaranteed. Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
