On Tue, Feb 09, 2010 at 10:28:15AM -0700, Grant Likely wrote: [...] > Rather than having a lock at the device tree data pointer level which > mixes usage with potentially many other drivers; wouldn't it make more > sense to use a mutex at the of_gc subsystem context?
I don't think so. of_gc = np->data; lock(of_gc); (or lock(devtree)) <do something with of_gc> doesn't provide us what we need, i.e. it doesn't guarantee that np->data (of_gc) is still alive. And here: lock(np->data); (or lock(devtree)) of_gc = np->data; lock(of_gc); <do something with of_gc> The second lock becomes useless (unless you also refcount np->data usage and can drop the devtree/np->data lock, and grab some other kind of lock, e.g. mutex, but this is silly). Thanks, -- Anton Vorontsov email: cbouatmai...@gmail.com irc://irc.freenode.net/bd2 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
