[PATCH v4 07/12] crypto: atmel-i2c - introduce shared teardown helpers and fix queue flush

[Lothar Rubusch]

Introduce atmel_i2c_deactivate_client() and atmel_i2c_unregister_client()
helpers in the atmel-i2c core library to modularize client teardown. This
encapsulates common client state tracking and list manipulation operations.

Convert the ECC driver's error recovery and device removal paths to utilize
these new helpers, ensuring consistent execution ordering when modifying
device-readiness states and deleting linked-list nodes.

Additionally, migrate the atmel_i2c_flush_queue() call out of the module
exit path. It now runs inside the core unregistration helper. Export both
new tracking symbols via EXPORT_SYMBOL_GPL() to match the existing core
driver licensing standard.

Signed-off-by: Lothar Rubusch <l.rubusch at gmail.com>
---
 drivers/crypto/atmel-ecc.c | 25 ++++++-------------------
 drivers/crypto/atmel-i2c.c | 20 ++++++++++++++++++++
 drivers/crypto/atmel-i2c.h |  3 +++
 3 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/drivers/crypto/atmel-ecc.c b/drivers/crypto/atmel-ecc.c
index 1ae9c52812df..e6d3e6574251 100644
--- a/drivers/crypto/atmel-ecc.c
+++ b/drivers/crypto/atmel-ecc.c
@@ -351,12 +351,8 @@ static int atmel_ecc_probe(struct i2c_client *client)
 						      msecs_to_jiffies(2000));
 		mutex_lock(&atmel_ecc_kpp_lock);
 		if (timeout == 0) {
-			spin_lock(&atmel_i2c_mgmt.i2c_list_lock);
-			i2c_priv->ready = false;
-			list_del(&i2c_priv->i2c_client_list_node);
-			spin_unlock(&atmel_i2c_mgmt.i2c_list_lock);
-			mutex_unlock(&atmel_ecc_kpp_lock);
-
+			atmel_i2c_deactivate_client(i2c_priv);
+			atmel_i2c_unregister_client(i2c_priv);
 			dev_err(&client->dev, "probe timed out, former driver instance not fully deregistered\n");
 			return -ETIMEDOUT;
 		}
@@ -365,12 +361,8 @@ static int atmel_ecc_probe(struct i2c_client *client)
 	if (atmel_ecc_kpp_refcnt == 0) {
 		ret = crypto_register_kpp(&atmel_ecdh_nist_p256);
 		if (ret) {
-			spin_lock(&atmel_i2c_mgmt.i2c_list_lock);
-			i2c_priv->ready = false;
-			list_del(&i2c_priv->i2c_client_list_node);
-			spin_unlock(&atmel_i2c_mgmt.i2c_list_lock);
-			mutex_unlock(&atmel_ecc_kpp_lock);
-
+			atmel_i2c_deactivate_client(i2c_priv);
+			atmel_i2c_unregister_client(i2c_priv);
 			dev_err(&client->dev, "%s alg registration failed\n",
 				atmel_ecdh_nist_p256.base.cra_driver_name);
 			return ret;
@@ -388,9 +380,7 @@ static void atmel_ecc_remove(struct i2c_client *client)
 	struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
 	bool trigger_unreg = false;
 
-	spin_lock(&atmel_i2c_mgmt.i2c_list_lock);
-	i2c_priv->ready = false;
-	spin_unlock(&atmel_i2c_mgmt.i2c_list_lock);
+	atmel_i2c_deactivate_client(i2c_priv);
 
 	/*
 	 * The Linux crypto core automatically blocks until all active
@@ -410,9 +400,7 @@ static void atmel_ecc_remove(struct i2c_client *client)
 	if (atomic_read(&i2c_priv->tfm_count))
 		wait_for_completion(&i2c_priv->remove_done);
 
-	spin_lock(&atmel_i2c_mgmt.i2c_list_lock);
-	list_del(&i2c_priv->i2c_client_list_node);
-	spin_unlock(&atmel_i2c_mgmt.i2c_list_lock);
+	atmel_i2c_unregister_client(i2c_priv);
 
 	/*
 	 * The driver registers once an algorithm, but maintains a list of
@@ -461,7 +449,6 @@ static int __init atmel_ecc_init(void)
 
 static void __exit atmel_ecc_exit(void)
 {
-	atmel_i2c_flush_queue();
 	i2c_del_driver(&atmel_ecc_driver);
 }
 
diff --git a/drivers/crypto/atmel-i2c.c b/drivers/crypto/atmel-i2c.c
index a42b0ea30033..db818ce55033 100644
--- a/drivers/crypto/atmel-i2c.c
+++ b/drivers/crypto/atmel-i2c.c
@@ -354,6 +354,26 @@ static int device_sanity_check(struct i2c_client *client)
 	return ret;
 }
 
+void atmel_i2c_deactivate_client(struct atmel_i2c_client_priv *i2c_priv)
+{
+	spin_lock(&atmel_i2c_mgmt.i2c_list_lock);
+	i2c_priv->ready = false;
+	spin_unlock(&atmel_i2c_mgmt.i2c_list_lock);
+}
+EXPORT_SYMBOL_GPL(atmel_i2c_deactivate_client);
+
+void atmel_i2c_unregister_client(struct atmel_i2c_client_priv *i2c_priv)
+{
+	spin_lock(&atmel_i2c_mgmt.i2c_list_lock);
+	if (!list_empty(&i2c_priv->i2c_client_list_node))
+		list_del_init(&i2c_priv->i2c_client_list_node);
+	spin_unlock(&atmel_i2c_mgmt.i2c_list_lock);
+
+	/* don't sleep inside spin locks */
+	atmel_i2c_flush_queue();
+}
+EXPORT_SYMBOL_GPL(atmel_i2c_unregister_client);
+
 int atmel_i2c_probe(struct i2c_client *client)
 {
 	struct atmel_i2c_client_priv *i2c_priv;
diff --git a/drivers/crypto/atmel-i2c.h b/drivers/crypto/atmel-i2c.h
index 82321c35c21f..07fd2248e20b 100644
--- a/drivers/crypto/atmel-i2c.h
+++ b/drivers/crypto/atmel-i2c.h
@@ -193,4 +193,7 @@ void atmel_i2c_init_genkey_cmd(struct atmel_i2c_cmd *cmd, u16 keyid);
 int atmel_i2c_init_ecdh_cmd(struct atmel_i2c_cmd *cmd,
 			    struct scatterlist *pubkey);
 
+void atmel_i2c_deactivate_client(struct atmel_i2c_client_priv *i2c_priv);
+void atmel_i2c_unregister_client(struct atmel_i2c_client_priv *i2c_priv);
+
 #endif /* __ATMEL_I2C_H__ */
-- 
2.39.5