crypto: introduce: acomp_is_async to expose if comp drivers might sleep

crypto: introduce: acomp_is_async to expose if comp drivers might sleep

acomp's users might want to know if acomp is really async to optimize
themselves.  One typical user which can benefit from exposed async stat is
zswap.

In zswap, zsmalloc is the most commonly used allocator for (and perhaps
the only one).  For zsmalloc, we cannot sleep while we map the compressed
memory, so we copy it to a temporary buffer.  By knowing the alg won't
sleep can help zswap to avoid the need for a buffer.  This shows
noticeable improvement in load/store latency of zswap.

Link: https://lkml.kernel.org/r/20240222081135.173040-2-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Chris Li <chrisl@kernel.org>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>