linux-kernel - [PATCH v9 12/19] crypto: iaa - Enable async mode and make it the default.

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Message-Id: <20250430205305.22844-13-kanchana.p.sridhar@intel.com>
Date: Wed, 30 Apr 2025 13:52:58 -0700
From: Kanchana P Sridhar <kanchana.p.sridhar@...el.com>
To: linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	hannes@...xchg.org,
	yosry.ahmed@...ux.dev,
	nphamcs@...il.com,
	chengming.zhou@...ux.dev,
	usamaarif642@...il.com,
	ryan.roberts@....com,
	21cnbao@...il.com,
	ying.huang@...ux.alibaba.com,
	akpm@...ux-foundation.org,
	linux-crypto@...r.kernel.org,
	herbert@...dor.apana.org.au,
	davem@...emloft.net,
	clabbe@...libre.com,
	ardb@...nel.org,
	ebiggers@...gle.com,
	surenb@...gle.com,
	kristen.c.accardi@...el.com
Cc: wajdi.k.feghali@...el.com,
	vinodh.gopal@...el.com,
	kanchana.p.sridhar@...el.com
Subject: [PATCH v9 12/19] crypto: iaa - Enable async mode and make it the default.

This patch enables the 'async' sync_mode in the driver. Further, it sets
the default sync_mode to 'async', which makes it easier for IAA hardware
acceleration in the iaa_crypto driver to be loaded by default in the most
efficient/recommended 'async' mode for parallel
compressions/decompressions, namely, asynchronous submission of
descriptors, followed by polling for job completions. Earlier, the
"sync" mode used to be the default.

The iaa_crypto driver documentation has been updated with these
changes.

This way, anyone who wants to use IAA for zswap/zram can do so after
building the kernel, and without having to go through these steps to use
async mode:

  1) disable all the IAA device/wq bindings that happen at boot time
  2) rmmod iaa_crypto
  3) modprobe iaa_crypto
  4) echo async > /sys/bus/dsa/drivers/crypto/sync_mode
  5) re-run initialization of the IAA devices and wqs

Signed-off-by: Kanchana P Sridhar <kanchana.p.sridhar@...el.com>
---
 Documentation/driver-api/crypto/iaa/iaa-crypto.rst | 11 ++---------
 drivers/crypto/intel/iaa/iaa_crypto_main.c         |  4 ++--
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/Documentation/driver-api/crypto/iaa/iaa-crypto.rst b/Documentation/driver-api/crypto/iaa/iaa-crypto.rst
index 949bfa1ef624..8e0e98d50972 100644
--- a/Documentation/driver-api/crypto/iaa/iaa-crypto.rst
+++ b/Documentation/driver-api/crypto/iaa/iaa-crypto.rst
@@ -272,7 +272,7 @@ The available attributes are:
       echo async_irq > /sys/bus/dsa/drivers/crypto/sync_mode
 
     Async mode without interrupts (caller must poll) can be enabled by
-    writing 'async' to it (please see Caveat)::
+    writing 'async' to it::
 
       echo async > /sys/bus/dsa/drivers/crypto/sync_mode
 
@@ -281,14 +281,7 @@ The available attributes are:
 
       echo sync > /sys/bus/dsa/drivers/crypto/sync_mode
 
-    The default mode is 'sync'.
-
-    Caveat: since the only mechanism that iaa_crypto currently implements
-    for async polling without interrupts is via the 'sync' mode as
-    described earlier, writing 'async' to
-    '/sys/bus/dsa/drivers/crypto/sync_mode' will internally enable the
-    'sync' mode. This is to ensure correct iaa_crypto behavior until true
-    async polling without interrupts is enabled in iaa_crypto.
+    The default mode is 'async'.
 
   - g_comp_wqs_per_iaa
 
diff --git a/drivers/crypto/intel/iaa/iaa_crypto_main.c b/drivers/crypto/intel/iaa/iaa_crypto_main.c
index d577f555d6ab..cfd4f5ead67b 100644
--- a/drivers/crypto/intel/iaa/iaa_crypto_main.c
+++ b/drivers/crypto/intel/iaa/iaa_crypto_main.c
@@ -115,7 +115,7 @@ static bool iaa_verify_compress = true;
  */
 
 /* Use async mode */
-static bool async_mode;
+static bool async_mode = true;
 /* Use interrupts */
 static bool use_irq;
 
@@ -169,7 +169,7 @@ static int set_iaa_sync_mode(const char *name)
 		async_mode = false;
 		use_irq = false;
 	} else if (sysfs_streq(name, "async")) {
-		async_mode = false;
+		async_mode = true;
 		use_irq = false;
 	} else if (sysfs_streq(name, "async_irq")) {
 		async_mode = true;
-- 
2.27.0