Patch "hwrng: amd - Revert managed API changes" has been added to the 4.10-stable tree

This is a note to let you know that I've just added the patch titled

hwrng: amd - Revert managed API changes

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
hwrng-amd-revert-managed-api-changes.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Prarit Bhargava <[email protected]>
Date: Tue, 14 Mar 2017 07:36:01 -0400
Subject: hwrng: amd - Revert managed API changes

From: Prarit Bhargava <[email protected]>

commit 69db7009318758769d625b023402161c750f7876 upstream.

After commit 31b2a73c9c5f ("hwrng: amd - Migrate to managed API"), the amd-rng driver uses devres with pci_dev->dev to keep track of resources, but does not actually register a PCI driver. This results in the following issues:

1. The message

WARNING: CPU: 2 PID: 621 at drivers/base/dd.c:349 driver_probe_device+0x38c

is output when the i2c_amd756 driver loads and attempts to register a PCI driver. The PCI & device subsystems assume that no resources have been registered for the device, and the WARN_ON() triggers since amd-rng has already do so.

2. The driver leaks memory because the driver does not attach to a
device. The driver only uses the PCI device as a reference. devm_*()
functions will release resources on driver detach, which the amd-rng driver will never do. As a result,

3. The driver cannot be reloaded because there is always a use of the ioport and region after the first load of the driver.

Revert the changes made by 31b2a73c9c5f ("hwrng: amd - Migrate to managed API").

---
 drivers/char/hw_random/amd-rng.c |   42 +++++++++++++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 8 deletions(-)

@@ -55,6 +55,7 @@ MODULE_DEVICE_TABLE(pci, pci_tbl);
 struct amd768_priv {
 	void __iomem *iobase;
 	struct pci_dev *pcidev;
+	u32 pmbase;
 };
 
 static int amd_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)

@@ -148,33 +149,58 @@ found:
 	if (pmbase == 0)
 		return -EIO;
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	if (!devm_request_region(&pdev->dev, pmbase + PMBASE_OFFSET,
-				PMBASE_SIZE, DRV_NAME)) {
+	if (!request_region(pmbase + PMBASE_OFFSET, PMBASE_SIZE, DRV_NAME)) {
 		dev_err(&pdev->dev, DRV_NAME " region 0x%x already in use!\n",
 			pmbase + 0xF0);
-		return -EBUSY;
+		err = -EBUSY;
+		goto out;
 	}
 
-	priv->iobase = devm_ioport_map(&pdev->dev, pmbase + PMBASE_OFFSET,
-			PMBASE_SIZE);
+	priv->iobase = ioport_map(pmbase + PMBASE_OFFSET, PMBASE_SIZE);
 	if (!priv->iobase) {
 		pr_err(DRV_NAME "Cannot map ioport\n");
-		return -ENOMEM;
+		err = -EINVAL;
+		goto err_iomap;
 	}
 
 	amd_rng.priv = (unsigned long)priv;
+	priv->pmbase = pmbase;
 	priv->pcidev = pdev;
 
 	pr_info(DRV_NAME " detected\n");
-	return devm_hwrng_register(&pdev->dev, &amd_rng);
+	err = hwrng_register(&amd_rng);
+	if (err) {
+		pr_err(DRV_NAME " registering failed (%d)\n", err);
+		goto err_hwrng;
+	}
+	return 0;
+
+err_hwrng:
+	ioport_unmap(priv->iobase);
+err_iomap:
+	release_region(pmbase + PMBASE_OFFSET, PMBASE_SIZE);
+out:
+	kfree(priv);
+	return err;
 }
 
 static void __exit mod_exit(void)
 {
+	struct amd768_priv *priv;
+
+	priv = (struct amd768_priv *)amd_rng.priv;
+
+	hwrng_unregister(&amd_rng);
+
+	ioport_unmap(priv->iobase);
+
+	release_region(priv->pmbase + PMBASE_OFFSET, PMBASE_SIZE);
+
+	kfree(priv);
 }
 
 module_init(mod_init);

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/hwrng-amd-revert-managed-api-changes.patch queue-4.10/hwrng-geode-revert-managed-api-changes.patch