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PCI: Protect pci_driver->sriov_configure() usage with device_lock()

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Every method in struct device_driver or structures derived from it like
struct pci_driver MUST provide exclusion vs the driver's ->remove() method,
usually by using device_lock().

Protect use of pci_driver->sriov_configure() by holding the device lock
while calling it.

The PCI core sets the pci_dev->driver pointer in local_pci_probe() before
calling ->probe() and only clears it after ->remove().  This means driver's
->sriov_configure() callback will happily race with probe() and remove(),
most likely leading to BUGs, since drivers don't expect this.

Remove the iov lock completely, since we remove the last user.

[bhelgaas: changelog, thanks to Christoph for locking rule]
Link: http://lkml.kernel.org/r/20170522225023.14010-1-jakub.kicinski@netronome.com
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Jakub Kicinski 2017-05-22 15:50:23 -07:00 committed by Bjorn Helgaas
parent d40b7fd2cb
commit 17530e71e0
3 changed files with 2 additions and 8 deletions
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4
drivers/pci/iov.c
View File

@ -461,8 +461,6 @@ found:
else
iov->dev = dev;
mutex_init(&iov->lock);
dev->sriov = iov;
dev->is_physfn = 1;
rc = compute_max_vf_buses(dev);
@ -491,8 +489,6 @@ static void sriov_release(struct pci_dev *dev)
if (dev != dev->sriov->dev)
pci_dev_put(dev->sriov->dev);
mutex_destroy(&dev->sriov->lock);
kfree(dev->sriov);
dev->sriov = NULL;
}

5
drivers/pci/pci-sysfs.c
View File

@ -472,7 +472,6 @@ static ssize_t sriov_numvfs_store(struct device *dev,
const char *buf, size_t count)
{
struct pci_dev *pdev = to_pci_dev(dev);
struct pci_sriov *iov = pdev->sriov;
int ret;
u16 num_vfs;
@ -483,7 +482,7 @@ static ssize_t sriov_numvfs_store(struct device *dev,
if (num_vfs > pci_sriov_get_totalvfs(pdev))
return -ERANGE;
mutex_lock(&iov->dev->sriov->lock);
device_lock(&pdev->dev);
if (num_vfs == pdev->sriov->num_VFs)
goto exit;
@ -518,7 +517,7 @@ static ssize_t sriov_numvfs_store(struct device *dev,
num_vfs, ret);
exit:
mutex_unlock(&iov->dev->sriov->lock);
device_unlock(&pdev->dev);
if (ret < 0)
return ret;

1
drivers/pci/pci.h
View File

@ -272,7 +272,6 @@ struct pci_sriov {
u16 driver_max_VFs; /* max num VFs driver supports */
struct pci_dev *dev; /* lowest numbered PF */
struct pci_dev *self; /* this PF */
struct mutex lock; /* lock for setting sriov_numvfs in sysfs */
resource_size_t barsz[PCI_SRIOV_NUM_BARS]; /* VF BAR size */
bool drivers_autoprobe; /* auto probing of VFs by driver */
};