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hwrng: amd - Revert managed API changes 

After commit 31b2a73c9c ("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 31b2a73c9c ("hwrng: amd - Migrate to managed
API").

Cc: <stable@vger.kernel.org>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Fixes: 31b2a73c9c ("hwrng: amd - Migrate to managed API").
Cc: Matt Mackall <mpm@selenic.com>
Cc: Corentin LABBE <clabbe.montjoie@gmail.com>
Cc: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-geode@lists.infradead.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Prarit Bhargava 2017-03-14 07:36:01 -04:00 committed by Herbert Xu
parent 7c468447f4
commit 69db700931
1 changed files with 34 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
drivers/char/hw_random/amd-rng.c
View File

@ -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);