[PATCH 09/12] crypto: atmel - check client data in remove callbacks

[Lothar Rubusch <l.rubusch@gmail.com>]

Check the i2c client private data pointer in the remove callbacks of
the Atmel ECC and SHA204A drivers before accessing driver state.
Move sysfs group removal ahead of the NULL check so cleanup can still
proceed even if client data is unavailable. Also downgrade the
busy-device warning in the ECC remove path from dev_emerg() to
dev_warn().

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/crypto/atmel-ecc.c     | 20 ++++++--------------
 drivers/crypto/atmel-sha204a.c |  7 +++++--
 2 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/drivers/crypto/atmel-ecc.c b/drivers/crypto/atmel-ecc.c
index f6d1a9694d63..9ad6d42b6eef 100644
--- a/drivers/crypto/atmel-ecc.c
+++ b/drivers/crypto/atmel-ecc.c
@@ -380,19 +380,13 @@ static void atmel_ecc_remove(struct i2c_client *client)
 {
 	struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
 
-	/* Return EBUSY if i2c client already allocated. */
-	if (atomic_read(&i2c_priv->tfm_count)) {
-		/*
-		 * After we return here, the memory backing the device is freed.
-		 * That happens no matter what the return value of this function
-		 * is because in the Linux device model there is no error
-		 * handling for unbinding a driver.
-		 * If there is still some action pending, it probably involves
-		 * accessing the freed memory.
-		 */
-		dev_emerg(&client->dev, "Device is busy, expect memory corruption.\n");
+	sysfs_remove_group(&client->dev.kobj, &atmel_ecc508a_groups);
+
+	if (!i2c_priv)
 		return;
-	}
+
+	if (atomic_read(&i2c_priv->tfm_count))
+		dev_warn(&client->dev, "Device is busy, remove it anyhow\n");
 
 	atmel_i2c_unregister_client(i2c_priv);
 	atmel_i2c_flush_queue();
@@ -403,8 +397,6 @@ static void atmel_ecc_remove(struct i2c_client *client)
 		kfree((void *)i2c_priv->hwrng.priv);
 		i2c_priv->hwrng.priv = 0;
 	}
-
-	sysfs_remove_group(&client->dev.kobj, &atmel_ecc508a_groups);
 }
 
 static const struct atmel_i2c_of_match_data atecc508a_match_data = {
diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c
index 88726f6ef87c..6a41024ae40d 100644
--- a/drivers/crypto/atmel-sha204a.c
+++ b/drivers/crypto/atmel-sha204a.c
@@ -111,6 +111,11 @@ static void atmel_sha204a_remove(struct i2c_client *client)
 {
 	struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
 
+	sysfs_remove_group(&client->dev.kobj, &atmel_sha204a_groups);
+
+	if (!i2c_priv)
+		return;
+
 	devm_hwrng_unregister(&client->dev, &i2c_priv->hwrng);
 	atmel_i2c_flush_queue();
 
@@ -118,8 +123,6 @@ static void atmel_sha204a_remove(struct i2c_client *client)
 		kfree((void *)i2c_priv->hwrng.priv);
 		i2c_priv->hwrng.priv = 0;
 	}
-
-	sysfs_remove_group(&client->dev.kobj, &atmel_sha204a_groups);
 }
 
 static const struct atmel_i2c_of_match_data atsha204_match_data = {
-- 
2.53.0