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    Subject[PATCH v5 5/9] pci: Split out pci_dev lock/unlock and save/restore
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    Date
    Only cosmetic code changes to existing paths.  Expand the comment in
    the new pci_dev_save_and_disable() function since there's a lot
    hidden in that Command register write.

    Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
    ---
    drivers/pci/pci.c | 55 +++++++++++++++++++++++++++++++++++++----------------
    1 file changed, 38 insertions(+), 17 deletions(-)

    diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
    index 9407aab..4a0275c 100644
    --- a/drivers/pci/pci.c
    +++ b/drivers/pci/pci.c
    @@ -3317,22 +3317,49 @@ done:
    return rc;
    }

    +static void pci_dev_lock(struct pci_dev *dev)
    +{
    + pci_cfg_access_lock(dev);
    + /* block PM suspend, driver probe, etc. */
    + device_lock(&dev->dev);
    +}
    +
    +static void pci_dev_unlock(struct pci_dev *dev)
    +{
    + device_unlock(&dev->dev);
    + pci_cfg_access_unlock(dev);
    +}
    +
    +static void pci_dev_save_and_disable(struct pci_dev *dev)
    +{
    + pci_save_state(dev);
    + /*
    + * Disable the device by clearing the Command register, except for
    + * INTx-disable which is set. This not only disable MMIO and I/O port
    + * BARs, but also prevents the device from being Bus Master, preventing
    + * DMA from the device including MSI/MSI-X interrupts. For PCI 2.3
    + * compliant devices, INTx-disable prevents legacy interrupts.
    + */
    + pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
    +}
    +
    +static void pci_dev_restore(struct pci_dev *dev)
    +{
    + pci_restore_state(dev);
    +}
    +
    static int pci_dev_reset(struct pci_dev *dev, int probe)
    {
    int rc;

    - if (!probe) {
    - pci_cfg_access_lock(dev);
    - /* block PM suspend, driver probe, etc. */
    - device_lock(&dev->dev);
    - }
    + if (!probe)
    + pci_dev_lock(dev);

    rc = __pci_dev_reset(dev, probe);

    - if (!probe) {
    - device_unlock(&dev->dev);
    - pci_cfg_access_unlock(dev);
    - }
    + if (!probe)
    + pci_dev_unlock(dev);
    +
    return rc;
    }
    /**
    @@ -3423,17 +3450,11 @@ int pci_reset_function(struct pci_dev *dev)
    if (rc)
    return rc;

    - pci_save_state(dev);
    -
    - /*
    - * both INTx and MSI are disabled after the Interrupt Disable bit
    - * is set and the Bus Master bit is cleared.
    - */
    - pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
    + pci_dev_save_and_disable(dev);

    rc = pci_dev_reset(dev, 0);

    - pci_restore_state(dev);
    + pci_dev_restore(dev);

    return rc;
    }


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