[PATCH 7.0.y 1/2] EDAC/versalnet: Refactor memory controller initialization and cleanup

[Sasha Levin <sashal@kernel.org>]

From: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>

[ Upstream commit 62a9fc50e8d947601ea3484e732b1a65a0a54b96 ]

Simplify the initialization and cleanup flow for Versal Net DDRMC
controllers in the EDAC driver by carving out the single controller init
into a separate function which allows for a much better and more
readable error handling and unwinding.

  [ bp:
	- do the kzalloc allocations first
	- "publish" the structures only after they've been initialized
	  properly so that you don't need to unwind unnecessarily when
	  it fails later
	- remove_versalnet() is now trivial
   ]

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20251104093932.3838876-1-shubhrajyoti.datta@amd.com
Stable-dep-of: 8cf5dd235eff ("EDAC/versalnet: Fix device name memory leak")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/edac/versalnet_edac.c | 174 +++++++++++++++++++---------------
 1 file changed, 97 insertions(+), 77 deletions(-)

diff --git a/drivers/edac/versalnet_edac.c b/drivers/edac/versalnet_edac.c
index 162fb1736f55f..ec13155824141 100644
--- a/drivers/edac/versalnet_edac.c
+++ b/drivers/edac/versalnet_edac.c
@@ -70,6 +70,8 @@
 #define XDDR5_BUS_WIDTH_32		1
 #define XDDR5_BUS_WIDTH_16		2
 
+#define MC_NAME_LEN			32
+
 /**
  * struct ecc_error_info - ECC error log information.
  * @burstpos:		Burst position.
@@ -760,7 +762,17 @@ static void versal_edac_release(struct device *dev)
 	kfree(dev);
 }
 
-static int init_versalnet(struct mc_priv *priv, struct platform_device *pdev)
+static void remove_one_mc(struct mc_priv *priv, int i)
+{
+	struct mem_ctl_info *mci;
+
+	mci = priv->mci[i];
+	device_unregister(mci->pdev);
+	edac_mc_del_mc(mci->pdev);
+	edac_mc_free(mci);
+}
+
+static int init_one_mc(struct mc_priv *priv, struct platform_device *pdev, int i)
 {
 	u32 num_chans, rank, dwidth, config;
 	struct edac_mc_layer layers[2];
@@ -768,102 +780,110 @@ static int init_versalnet(struct mc_priv *priv, struct platform_device *pdev)
 	struct device *dev;
 	enum dev_type dt;
 	char *name;
-	int rc, i;
-
-	for (i = 0; i < NUM_CONTROLLERS; i++) {
-		config = priv->adec[CONF + i * ADEC_NUM];
-		num_chans = FIELD_GET(MC5_NUM_CHANS_MASK, config);
-		rank = 1 << FIELD_GET(MC5_RANK_MASK, config);
-		dwidth = FIELD_GET(MC5_BUS_WIDTH_MASK, config);
-
-		switch (dwidth) {
-		case XDDR5_BUS_WIDTH_16:
-			dt = DEV_X16;
-			break;
-		case XDDR5_BUS_WIDTH_32:
-			dt = DEV_X32;
-			break;
-		case XDDR5_BUS_WIDTH_64:
-			dt = DEV_X64;
-			break;
-		default:
-			dt = DEV_UNKNOWN;
-		}
+	int rc;
 
-		if (dt == DEV_UNKNOWN)
-			continue;
+	config = priv->adec[CONF + i * ADEC_NUM];
+	num_chans = FIELD_GET(MC5_NUM_CHANS_MASK, config);
+	rank = 1 << FIELD_GET(MC5_RANK_MASK, config);
+	dwidth = FIELD_GET(MC5_BUS_WIDTH_MASK, config);
+
+	switch (dwidth) {
+	case XDDR5_BUS_WIDTH_16:
+		dt = DEV_X16;
+		break;
+	case XDDR5_BUS_WIDTH_32:
+		dt = DEV_X32;
+		break;
+	case XDDR5_BUS_WIDTH_64:
+		dt = DEV_X64;
+		break;
+	default:
+		dt = DEV_UNKNOWN;
+	}
 
-		/* Find the first enabled device and register that one. */
-		layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
-		layers[0].size = rank;
-		layers[0].is_virt_csrow = true;
-		layers[1].type = EDAC_MC_LAYER_CHANNEL;
-		layers[1].size = num_chans;
-		layers[1].is_virt_csrow = false;
+	if (dt == DEV_UNKNOWN)
+		return 0;
 
-		rc = -ENOMEM;
-		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_alloc;
-		}
+	/* Find the first enabled device and register that one. */
+	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
+	layers[0].size = rank;
+	layers[0].is_virt_csrow = true;
+	layers[1].type = EDAC_MC_LAYER_CHANNEL;
+	layers[1].size = num_chans;
+	layers[1].is_virt_csrow = false;
+
+	rc = -ENOMEM;
+	name = kzalloc(MC_NAME_LEN, GFP_KERNEL);
+	if (!name)
+		return rc;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		goto err_name_free;
+
+	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;
+	}
 
-		priv->mci[i] = mci;
-		priv->dwidth = dt;
+	sprintf(name, "versal-net-ddrmc5-edac-%d", i);
 
-		dev = kzalloc_obj(*dev);
-		dev->release = versal_edac_release;
-		name = kmalloc(32, GFP_KERNEL);
-		sprintf(name, "versal-net-ddrmc5-edac-%d", i);
-		dev->init_name = name;
-		rc = device_register(dev);
-		if (rc)
-			goto err_alloc;
+	dev->init_name = name;
+	dev->release = versal_edac_release;
 
-		mci->pdev = dev;
+	rc = device_register(dev);
+	if (rc)
+		goto err_mc_free;
 
-		platform_set_drvdata(pdev, priv);
+	mci->pdev = dev;
+	mc_init(mci, dev);
 
-		mc_init(mci, dev);
-		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_alloc;
-		}
+	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;
 	}
-	return 0;
 
-err_alloc:
-	while (i--) {
-		mci = priv->mci[i];
-		if (!mci)
-			continue;
-
-		if (mci->pdev) {
-			device_unregister(mci->pdev);
-			edac_mc_del_mc(mci->pdev);
-		}
+	priv->mci[i] = mci;
+	priv->dwidth = dt;
 
-		edac_mc_free(mci);
-	}
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+
+err_unreg:
+	device_unregister(mci->pdev);
+err_mc_free:
+	edac_mc_free(mci);
+err_dev_free:
+	kfree(dev);
+err_name_free:
+	kfree(name);
 
 	return rc;
 }
 
-static void remove_versalnet(struct mc_priv *priv)
+static int init_versalnet(struct mc_priv *priv, struct platform_device *pdev)
 {
-	struct mem_ctl_info *mci;
-	int i;
+	int rc, i;
 
 	for (i = 0; i < NUM_CONTROLLERS; i++) {
-		device_unregister(priv->mci[i]->pdev);
-		mci = edac_mc_del_mc(priv->mci[i]->pdev);
-		if (!mci)
-			return;
+		rc = init_one_mc(priv, pdev, i);
+		if (rc) {
+			while (i--)
+				remove_one_mc(priv, i);
 
-		edac_mc_free(mci);
+			return rc;
+		}
 	}
+	return 0;
+}
+
+static void remove_versalnet(struct mc_priv *priv)
+{
+	for (int i = 0; i < NUM_CONTROLLERS; i++)
+		remove_one_mc(priv, i);
 }
 
 static int mc_probe(struct platform_device *pdev)
-- 
2.53.0