[PATCH v2 12/15] platform/chrome: use krealloc() for `din` and `dout`

[Tzung-Bi Shih <tzungbi@kernel.org>]

Use krealloc() to re-allocate `din` and `dout`.  Don't use devm variant
because the two buffers could be re-allocated multiple times during
runtime.  Their life cycles aren't quite aligned to the device's.

Free the memory in cros_ec_unregister() if any.

No need to free memory if krealloc() fails.  They will be freed
eventually in either of the following:
- Error handling path in cros_ec_register().
- In cros_ec_unregister().
- Next krealloc() in cros_ec_query_all().

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
Changes from v1:
- Don't use devm.
- Free in cros_ec_unregister().

 drivers/platform/chrome/cros_ec.c            |  4 +++
 drivers/platform/chrome/cros_ec_proto.c      | 29 +++++++-------------
 drivers/platform/chrome/cros_ec_proto_test.c |  3 +-
 3 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 29d3b544dafb..fb8cb8a73295 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -285,6 +285,8 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 exit:
 	platform_device_unregister(ec_dev->ec);
 	platform_device_unregister(ec_dev->pd);
+	kfree(ec_dev->din);
+	kfree(ec_dev->dout);
 	return err;
 }
 EXPORT_SYMBOL(cros_ec_register);
@@ -302,6 +304,8 @@ void cros_ec_unregister(struct cros_ec_device *ec_dev)
 	if (ec_dev->pd)
 		platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
+	kfree(ec_dev->din);
+	kfree(ec_dev->dout);
 }
 EXPORT_SYMBOL(cros_ec_unregister);
 
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 473654f50bca..de6bc457e496 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -469,9 +469,9 @@ static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev,
  */
 int cros_ec_query_all(struct cros_ec_device *ec_dev)
 {
-	struct device *dev = ec_dev->dev;
 	u32 ver_mask = 0;
 	int ret;
+	u8 *din, *dout;
 
 	/* First try sending with proto v3. */
 	if (!cros_ec_get_proto_info(ec_dev, CROS_EC_DEV_EC_INDEX)) {
@@ -492,21 +492,15 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
 		}
 	}
 
-	devm_kfree(dev, ec_dev->din);
-	devm_kfree(dev, ec_dev->dout);
-
-	ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
-	if (!ec_dev->din) {
-		ret = -ENOMEM;
-		goto exit;
-	}
+	din = krealloc(ec_dev->din, ec_dev->din_size, GFP_KERNEL);
+	if (!din)
+		return -ENOMEM;
+	ec_dev->din = din;
 
-	ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
-	if (!ec_dev->dout) {
-		devm_kfree(dev, ec_dev->din);
-		ret = -ENOMEM;
-		goto exit;
-	}
+	dout = krealloc(ec_dev->dout, ec_dev->dout_size, GFP_KERNEL);
+	if (!dout)
+		return -ENOMEM;
+	ec_dev->dout = dout;
 
 	/* Probe if MKBP event is supported */
 	ret = cros_ec_get_host_command_version_mask(ec_dev,
@@ -555,10 +549,7 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
 				"failed to retrieve wake mask: %d\n", ret);
 	}
 
-	ret = 0;
-
-exit:
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(cros_ec_query_all);
 
diff --git a/drivers/platform/chrome/cros_ec_proto_test.c b/drivers/platform/chrome/cros_ec_proto_test.c
index 730248be42a7..27b81a5a9880 100644
--- a/drivers/platform/chrome/cros_ec_proto_test.c
+++ b/drivers/platform/chrome/cros_ec_proto_test.c
@@ -180,8 +180,7 @@ static void cros_ec_proto_test_query_all_pretest(struct kunit *test)
 
 	/*
 	 * cros_ec_query_all() will free din and dout and allocate them again to fit the usage by
-	 * calling devm_kfree() and devm_kzalloc().  Set them to NULL as they aren't managed by
-	 * ec_dev->dev.
+	 * calling krealloc().  Set them to NULL as they aren't allocated by kalloc().
 	 */
 	ec_dev->din = NULL;
 	ec_dev->dout = NULL;
-- 
2.36.1.255.ge46751e96f-goog