On Tue, Feb 19, 2019 at 05:26:09PM -0800, Matthew Wilcox wrote: > On Tue, Feb 19, 2019 at 04:53:49PM -0700, Jason Gunthorpe wrote: > > Hey Matt, > > > > Did you intend that xa_release doesn't work on allocating arrays: > > That surprises me. I'll take a look in the morning.
I think the issue is that this: static inline void xa_release(struct xarray *xa, unsigned long index) { xa_cmpxchg(xa, index, NULL, NULL, 0); relies on the NULL actually being xas_store(NULL), but cmpxchg transforms it into xas_store(XA_ZERO_ENTRY) when allocating.. So xa_reserve(), xa_release() and xa_cmpxchg() all do the same thing for allocating arrays. Perhaps this: void __xa_release(struct xarray *xa, unsigned long index) { XA_STATE(xas, xa, index); void *curr; curr = xas_load(&xas); if (curr == XA_ZERO_ENTRY) xas_store(&xas, NULL); } ? Also, I wonder if xa_reserve() is better written as as xa_cmpxchg(xa, index, NULL, XA_ZERO_ENTRY) Bit clearer what is going on.. Jason