Re: [PATCH 4/8] rhashtable: fix race in nested_table_alloc()

Herbert Xu
2018-05-06T05:19:09Z

On Sun, May 06, 2018 at 07:48:20AM +1000, NeilBrown wrote:
>
> The spinlock protects 2 or more buckets. The nested table contains at
> least 512 buckets, maybe more.
> It is quite possible for two insertions into 2 different buckets to both
> get their spinlock and both try to instantiate the same nested table.

I think you missed the fact that when we use nested tables the spin
lock table is limited to just a single page and hence corresponds
to the first level in the nested table. Therefore it's always safe.

Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
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