On Fri, May 04, 2018 at 01:54:14PM +1000, NeilBrown wrote: > Rather than borrowing one of the bucket locks to > protect ->future_tbl updates, use cmpxchg(). > This gives more freedom to change how bucket locking > is implemented. > > Signed-off-by: NeilBrown <ne...@suse.com>
This looks nice. > - spin_unlock_bh(old_tbl->locks); > + rcu_assign_pointer(tmp, new_tbl); Do we need this barrier since cmpxchg is supposed to provide memory barrier semantics? > + if (cmpxchg(&old_tbl->future_tbl, NULL, tmp) != NULL) > + return -EEXIST; Thanks, -- Email: Herbert Xu <herb...@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
