[PATCH] EDAC/highbank_l2: manage dci lifetime via devres and simplify ioremap

[Rosen Penev <rosenp@gmail.com>]

Replace the open-coded platform_get_resource() +
devm_request_mem_region() + devm_ioremap() sequence with the single
helper devm_platform_ioremap_resource(), and move the platform_get_irq()
calls earlier, dropping the redundant -ENODEV/-EBUSY/-ENOMEM error
paths. (The previous open-coded resource check wrongly used IS_ERR() on
platform_get_resource()'s NULL return, which would never trigger.)

highbank_l2_err_probe() requests its interrupts with devm_request_irq(),
passing dci as the handler context, but highbank_l2_err_remove() frees
dci via edac_device_free_ctl_info() before devres releases the IRQs,
leaving a use-after-free window in the shared interrupt handler.
Register an edac_device_free_ctl_info() callback via
devm_add_action_or_reset() right after edac_device_alloc_ctl_info() so
dci is owned by devres and freed only after the IRQs are released. Drop
the explicit edac_device_free_ctl_info() from both the probe error path
and highbank_l2_err_remove(), and remove the now-redundant devres group
open/close/release calls.

Built for arm (CONFIG_EDAC_HIGHBANK) with LLVM=1;
drivers/edac/highbank_l2_edac.o compiles cleanly and passes checkpatch
--strict.

Assisted-by: opencode:hy3-free
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/edac/highbank_l2_edac.c | 67 +++++++++++++++------------------
 1 file changed, 31 insertions(+), 36 deletions(-)

diff --git a/drivers/edac/highbank_l2_edac.c b/drivers/edac/highbank_l2_edac.c
index 24f163ff323f..2436be7a32fe 100644
--- a/drivers/edac/highbank_l2_edac.c
+++ b/drivers/edac/highbank_l2_edac.c
@@ -45,85 +45,80 @@ static const struct of_device_id hb_l2_err_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, hb_l2_err_of_match);
 
+static void highbank_l2_edac_free(void *data)
+{
+	struct edac_device_ctl_info *dci = data;
+
+	edac_device_free_ctl_info(dci);
+}
+
 static int highbank_l2_err_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *id;
 	struct edac_device_ctl_info *dci;
 	struct hb_l2_drvdata *drvdata;
-	struct resource *r;
-	int res = 0;
+	void __iomem *base;
+	int db_irq;
+	int sb_irq;
+	int res;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	db_irq = platform_get_irq(pdev, 0);
+	if (db_irq < 0)
+		return db_irq;
+
+	sb_irq = platform_get_irq(pdev, 1);
+	if (sb_irq < 0)
+		return sb_irq;
 
 	dci = edac_device_alloc_ctl_info(sizeof(*drvdata), "cpu",
 					 1, "L", 1, 2, 0);
 	if (!dci)
 		return -ENOMEM;
 
+	if (devm_add_action_or_reset(&pdev->dev, highbank_l2_edac_free, dci))
+		return -ENOMEM;
+
 	drvdata = dci->pvt_info;
 	dci->dev = &pdev->dev;
 	platform_set_drvdata(pdev, dci);
 
-	if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL))
-		return -ENOMEM;
-
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!r) {
-		dev_err(&pdev->dev, "Unable to get mem resource\n");
-		res = -ENODEV;
-		goto err;
-	}
-
-	if (!devm_request_mem_region(&pdev->dev, r->start,
-				     resource_size(r), dev_name(&pdev->dev))) {
-		dev_err(&pdev->dev, "Error while requesting mem region\n");
-		res = -EBUSY;
-		goto err;
-	}
-
-	drvdata->base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
-	if (!drvdata->base) {
-		dev_err(&pdev->dev, "Unable to map regs\n");
-		res = -ENOMEM;
-		goto err;
-	}
-
 	id = of_match_device(hb_l2_err_of_match, &pdev->dev);
 	dci->mod_name = pdev->dev.driver->name;
 	dci->ctl_name = id ? id->compatible : "unknown";
 	dci->dev_name = dev_name(&pdev->dev);
 
 	if (edac_device_add_device(dci))
-		goto err;
+		return 0;
+
+	drvdata->base = base;
+	drvdata->db_irq = db_irq;
+	drvdata->sb_irq = sb_irq;
 
-	drvdata->db_irq = platform_get_irq(pdev, 0);
 	res = devm_request_irq(&pdev->dev, drvdata->db_irq,
 			       highbank_l2_err_handler,
 			       0, dev_name(&pdev->dev), dci);
 	if (res < 0)
 		goto err2;
 
-	drvdata->sb_irq = platform_get_irq(pdev, 1);
 	res = devm_request_irq(&pdev->dev, drvdata->sb_irq,
 			       highbank_l2_err_handler,
 			       0, dev_name(&pdev->dev), dci);
 	if (res < 0)
 		goto err2;
 
-	devres_close_group(&pdev->dev, NULL);
 	return 0;
 err2:
 	edac_device_del_device(&pdev->dev);
-err:
-	devres_release_group(&pdev->dev, NULL);
-	edac_device_free_ctl_info(dci);
 	return res;
 }
 
 static void highbank_l2_err_remove(struct platform_device *pdev)
 {
-	struct edac_device_ctl_info *dci = platform_get_drvdata(pdev);
-
 	edac_device_del_device(&pdev->dev);
-	edac_device_free_ctl_info(dci);
 }
 
 static struct platform_driver highbank_l2_edac_driver = {
-- 
2.55.0