Messages in this thread | | | Date | Tue, 19 Feb 2019 20:46:27 -0700 | From | Jason Gunthorpe <> | Subject | Re: xarray reserve/release? |
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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
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