On Thu, Nov 22, 2018 at 06:29:34PM +0800, Gao Xiang wrote: > Hi Greg, > > On 2018/11/22 18:21, Greg Kroah-Hartman wrote: > > On Tue, Nov 20, 2018 at 10:34:19PM +0800, Gao Xiang wrote: > >> There are two minor issues in the current freeze interface: > >> > >> 1) Freeze interfaces have not related with CONFIG_DEBUG_SPINLOCK, > >> therefore fix the incorrect conditions; > >> > >> 2) For SMP platforms, it should also disable preemption before > >> doing atomic_cmpxchg in case that some high priority tasks > >> preempt between atomic_cmpxchg and disable_preempt, then spin > >> on the locked refcount later. > > > > spinning on a refcount implies that you are trying to do your own type > > of locking. Why not use the in-kernel locking api instead? It will > > always do better than trying to do your own logic as the developers > > there know locking across all types of cpus better than filesystem > > developers :) > > It is because refcount also plays a role as a spinlock on a specific value > (== EROFS_LOCKED_MAGIC), no need to introduce such a value since the spin > window is small. As I said in another email, doing two things with one variable is odd as those are two different types of functions. greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
