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>

diff --git a/include/crypto/acompress.h b/include/crypto/acompress.h
index 574cffc90730f5f3296262375a08474dab6ec59d..80e243611fe243aa9b048efe282d472efc89f941 100644 (file)
--- a/include/crypto/acompress.h
+++ b/include/crypto/acompress.h
@@ -160,6 +160,12 @@ static inline void acomp_request_set_tfm(struct acomp_req *req,
        req->base.tfm = crypto_acomp_tfm(tfm);
 }
 
+static inline bool acomp_is_async(struct crypto_acomp *tfm)
+{
+       return crypto_comp_alg_common(tfm)->base.cra_flags &
+              CRYPTO_ALG_ASYNC;
+}
+
 static inline struct crypto_acomp *crypto_acomp_reqtfm(struct acomp_req *req)
 {
        return __crypto_acomp_tfm(req->base.tfm);