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Message-ID: <20251109155844.GUaRC6NHP2x4oO2Dk0@fat_crate.local>
Date: Sun, 9 Nov 2025 16:58:44 +0100
From: Borislav Petkov <bp@...en8.de>
To: Shubhrajyoti Datta <shubhrajyoti.datta@....com>
Cc: linux-kernel@...r.kernel.org, linux-edac@...r.kernel.org,
shubhrajyoti.datta@...il.com, Tony Luck <tony.luck@...el.com>,
James Morse <james.morse@....com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Robert Richter <rric@...nel.org>
Subject: Re: [PATCH v2] EDAC/versalnet: Refactor memory controller
initialization and cleanup
On Tue, Nov 04, 2025 at 03:09:20PM +0530, Shubhrajyoti Datta wrote:
> Simplify the initialization and cleanup flow for Versal Net DDRMC
> controllers in the EDAC driver.
>
> Introduce `init_single_versalnet()` for per-controller setup and
> `init_versalnet()` for looping through NUM_CONTROLLERS, also add
> rollback logic to handle partial init failures.
>
> Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@....com>
> ---
>
> Changes in v2:
> - Rename init_single_versalnet() to init_mc() for clarity.
> - Rename remove_single_versalnet() to remove_mc() to match naming convention.
> - Simplify error handling in init_versalnet() by replacing goto with a rollback loop.
> - Reduce indentation and consolidate cleanup logic.
Better, here's some more improvements and cleanups ontop. You probably should
apply the diff to better see what I mean:
- 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
Do run it on the hw and have the code fail at certain places on purpose to
make sure the unwinding happens properly.
HTH.
---
diff --git a/drivers/edac/versalnet_edac.c b/drivers/edac/versalnet_edac.c
index 01edc7408a5c..dc6108f7cee3 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.
@@ -758,7 +760,7 @@ static void versal_edac_release(struct device *dev)
kfree(dev);
}
-static void remove_mc(struct mc_priv *priv, int i)
+static void remove_one_mc(struct mc_priv *priv, int i)
{
struct mem_ctl_info *mci;
@@ -768,7 +770,7 @@ static void remove_mc(struct mc_priv *priv, int i)
edac_mc_free(mci);
}
-static int init_mc(struct mc_priv *priv, struct platform_device *pdev, int i)
+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];
@@ -809,41 +811,54 @@ static int init_mc(struct mc_priv *priv, struct platform_device *pdev, int i)
layers[1].is_virt_csrow = false;
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);
+ name = kzalloc(MC_NAME_LEN, GFP_KERNEL);
+ if (!name)
return rc;
- }
- priv->mci[i] = mci;
- priv->dwidth = dt;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
- goto err_mc_free;
- dev->release = versal_edac_release;
- name = kmalloc(32, GFP_KERNEL);
+ 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;
+ }
+
sprintf(name, "versal-net-ddrmc5-edac-%d", i);
+
dev->init_name = name;
+ dev->release = versal_edac_release;
+
rc = device_register(dev);
if (rc)
goto err_mc_free;
mci->pdev = dev;
-
- platform_set_drvdata(pdev, priv);
-
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_unreg;
}
+
+ priv->mci[i] = mci;
+ priv->dwidth = dt;
+
+ 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;
}
@@ -852,10 +867,10 @@ static int init_versalnet(struct mc_priv *priv, struct platform_device *pdev)
int rc, i;
for (i = 0; i < NUM_CONTROLLERS; i++) {
- rc = init_mc(priv, pdev, i);
+ rc = init_one_mc(priv, pdev, i);
if (rc) {
while (i--)
- remove_mc(priv, i);
+ remove_one_mc(priv, i);
return rc;
}
}
@@ -864,14 +879,8 @@ static int init_versalnet(struct mc_priv *priv, struct platform_device *pdev)
static void remove_versalnet(struct mc_priv *priv)
{
- struct mem_ctl_info *mci;
- int i;
-
- for (i = 0; i < NUM_CONTROLLERS; i++) {
- device_unregister(priv->mci[i]->pdev);
- mci = edac_mc_del_mc(priv->mci[i]->pdev);
- edac_mc_free(mci);
- }
+ for (int i = 0; i < NUM_CONTROLLERS; i++)
+ remove_one_mc(priv, i);
}
static int mc_probe(struct platform_device *pdev)
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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