On Sunday, October 30, 2016 05:22:13 PM Rafael J. Wysocki wrote: > Hi, > > Let me quote from the previous intro messages for this series first: > > > > Time for another update. :-) > > > > > > Fewer changes this time, mostly to address issues found by Lukas and > > > Marek. > > > > > > The most significant one is to make device_link_add() cope with the case > > > when > > > the consumer device has not been registered yet when it is called. The > > > supplier device still is required to be registered and the function will > > > return NULL if that is not the case. > > > > > > Another significant change is in patch [4/5] that now makes the core apply > > > pm_runtime_get_sync()/pm_runtime_put() to supplier devices around the > > > probing of a consumer one (in analogy with the parent). > > > > One more update after some conversations during LinuxCon Europe. > > > > The main point was to make it possible for device_link_add() to figure out > > the initial state of the link instead of expecting the caller to provide it > > which might not be reliable enough in general. > > > > In this version device_link_add() takes three arguments, the supplier and > > consumer pointers and flags and it sets the correct initial state of the > > link automatically (unless invoked with the "stateless" flag, of course). > > The cost is one additional field in struct device (I moved all of the > > links-related fields in struct device to a separate sub-structure while at > > it) to track the "driver presence status" of the device (to be used by > > device_link_add()). > > > > In addition to that, the links list walks in the core.c and dd.c code are > > under the device links mutex now, so the iternal link spinlock is not needed > > any more and I have renamed symbols to distinguish between flags, link > > states and device "driver presence statuses". > > The most significant change in this revision with respect to the previous one > is > related to the fact that SRCU is not available on some architectures, so the > code falls back to using an RW semaphore for synchronization if SRCU is not > there. Fortunately, the code changes needed for that turned out to be quite > straightforward and confined to the second patch. > > Apart from this, the flags are defined using BIT(x) now (instead of open > coding > the latter in the flag definitions). > > Updated is mostly patch [2/5]. Patches [1,3,5/5] have not changed (except for > trivial rebasing) and patch [4/5] needed to be refreshed on top of the > modified > [2/5]. > > FWIW, I've run the series through 0-day which has not reported any problems > with it.
BTW, the series is available from the device-links-test branch in my tree: git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git device-links-test in case someone wants to try it out. Thanks, Rafael
