[PATCH RFC 1/2] crypto: introduce acomp_is_async to expose if a acomp has a scomp backend

[Barry Song <21cnbao@gmail.com>]

From: Barry Song <v-songbaohua@oppo.com>

Almost all CPU-based compressors/decompressors are actually synchronous
though they support acomp APIs. While some chips have hardware-based
accelerators to offload CPU's work such as hisilicon and intel/qat/,
their drivers are working in async mode.
Letting acomp's users know exactly if the acomp is really async will
help users know if the compression and decompression procedure can
sleep and make their decisions accordingly.

Signed-off-by: Barry Song <v-songbaohua@oppo.com>
---
 crypto/acompress.c         | 8 ++++++++
 include/crypto/acompress.h | 9 +++++++++
 2 files changed, 17 insertions(+)

diff --git a/crypto/acompress.c b/crypto/acompress.c
index 1c682810a484..99118e879a4a 100644
--- a/crypto/acompress.c
+++ b/crypto/acompress.c
@@ -152,6 +152,14 @@ struct crypto_acomp *crypto_alloc_acomp_node(const char *alg_name, u32 type,
 }
 EXPORT_SYMBOL_GPL(crypto_alloc_acomp_node);
 
+bool acomp_is_async(struct crypto_acomp *acomp)
+{
+	struct crypto_tfm *tfm = crypto_acomp_tfm(acomp);
+
+	return tfm->__crt_alg->cra_type == &crypto_acomp_type;
+}
+EXPORT_SYMBOL_GPL(acomp_is_async);
+
 struct acomp_req *acomp_request_alloc(struct crypto_acomp *acomp)
 {
 	struct crypto_tfm *tfm = crypto_acomp_tfm(acomp);
diff --git a/include/crypto/acompress.h b/include/crypto/acompress.h
index 574cffc90730..5831080479e9 100644
--- a/include/crypto/acompress.h
+++ b/include/crypto/acompress.h
@@ -195,6 +195,15 @@ static inline int crypto_has_acomp(const char *alg_name, u32 type, u32 mask)
  */
 struct acomp_req *acomp_request_alloc(struct crypto_acomp *tfm);
 
+/**
+ * acomp_is_async() -- check if an acomp is asynchronous(can sleep)
+ *
+ * @tfm:	ACOMPRESS tfm handle allocated with crypto_alloc_acomp()
+ *
+ * Return:	true if the acomp is asynchronous, otherwise, false
+ */
+bool acomp_is_async(struct crypto_acomp *tfm);
+
 /**
  * acomp_request_free() -- zeroize and free asynchronous (de)compression
  *			   request as well as the output buffer if allocated
-- 
2.34.1