[PATCH 4/9] EDAC/versalnet: Fix device_register() error handling in init_one_mc()

[Shubhrajyoti Datta]

From: Prasanna Kumar T S M <ptsm@xxxxxxxxxxxxxxxxxxx>

When device_register() fails, it must be followed by put_device()
rather than kfree(), because device_register() calls
device_initialize() which sets up the device refcount. The matching
release function versal_edac_release() handles the actual kfree().

To simplify error handling and avoid complex unwinding, split
device_register() into device_initialize() and device_add().
Initialize the device early so put_device() can be used in all
error paths.

Fixes: d5fe2fec6c40 ("EDAC: Add a driver for the AMD Versal NET DDR controller")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Prasanna Kumar T S M <ptsm@xxxxxxxxxxxxxxxxxxx>
Co-authored-by: Copilot <223556219+Copilot@xxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxx>
---

 drivers/edac/versalnet_edac.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/edac/versalnet_edac.c b/drivers/edac/versalnet_edac.c
index 03b6e0958f17..3c9eaea5a106 100644
--- a/drivers/edac/versalnet_edac.c
+++ b/drivers/edac/versalnet_edac.c
@@ -785,7 +785,7 @@ static int init_one_mc(struct mc_priv *priv, int i)
 	char name[MC_NAME_LEN];
 	struct device *dev;
 	enum dev_type dt;
-	int rc;
+	int rc = -ENOMEM;
 
 	config = priv->adec[CONF + i * ADEC_NUM];
 	num_chans = FIELD_GET(MC5_NUM_CHANS_MASK, config);
@@ -817,23 +817,23 @@ static int init_one_mc(struct mc_priv *priv, int i)
 	layers[1].size = num_chans;
 	layers[1].is_virt_csrow = false;
 
-	rc = -ENOMEM;
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (!dev)
 		return rc;
 
-	mci = edac_mc_alloc(i, ARRAY_SIZE(layers), layers, sizeof(struct mc_priv));
-	if (!mci) {
-		edac_printk(KERN_ERR, EDAC_MC, "Failed memory allocation for MC%d\n", i);
-		goto err_dev_free;
-	}
-
 	sprintf(name, "versal-net-ddrmc5-edac-%d", i);
 
 	dev->init_name = name;
 	dev->release = versal_edac_release;
+	device_initialize(dev);
 
-	rc = device_register(dev);
+	mci = edac_mc_alloc(i, ARRAY_SIZE(layers), layers, sizeof(struct mc_priv));
+	if (!mci) {
+		edac_printk(KERN_ERR, EDAC_MC, "Failed memory allocation for MC%d\n", i);
+		goto err_put_dev;
+	}
+
+	rc = device_add(dev);
 	if (rc)
 		goto err_mc_free;
 
@@ -843,7 +843,7 @@ static int init_one_mc(struct mc_priv *priv, int i)
 	rc = edac_mc_add_mc(mci);
 	if (rc) {
 		edac_printk(KERN_ERR, EDAC_MC, "Failed to register MC%d with EDAC core\n", i);
-		goto err_unreg;
+		goto err_dev_del;
 	}
 
 	priv->mci[i] = mci;
@@ -851,12 +851,12 @@ static int init_one_mc(struct mc_priv *priv, int i)
 
 	return 0;
 
-err_unreg:
-	device_unregister(mci->pdev);
+err_dev_del:
+	device_del(dev);
 err_mc_free:
 	edac_mc_free(mci);
-err_dev_free:
-	kfree(dev);
+err_put_dev:
+	put_device(dev);
 
 	return rc;
 }
-- 
2.34.1