Re: [patch V2 20/23] PCI/MSI: Move msi_lock to struct pci_dev

Jason Gunthorpe
2021-12-08T15:29:33Z

On Mon, Dec 06, 2021 at 11:27:56PM +0100, Thomas Gleixner wrote:
> It's only required for PCI/MSI. So no point in having it in every struct
> device.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> V2: New patch
> ---
> drivers/base/core.c | 1 -
> drivers/pci/msi/msi.c | 2 +-
> drivers/pci/probe.c | 4 +++-
> include/linux/device.h | 2 --
> include/linux/pci.h | 1 +
> 5 files changed, 5 insertions(+), 5 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -2875,7 +2875,6 @@ void device_initialize(struct device *de
> device_pm_init(dev);
> set_dev_node(dev, NUMA_NO_NODE);
> #ifdef CONFIG_GENERIC_MSI_IRQ
> - raw_spin_lock_init(&dev->msi_lock);
> INIT_LIST_HEAD(&dev->msi_list);
> #endif
> INIT_LIST_HEAD(&dev->links.consumers);
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -18,7 +18,7 @@ int pci_msi_ignore_mask;
>
> static noinline void pci_msi_update_mask(struct msi_desc *desc, u32 clear, u32 set)
> {
> - raw_spinlock_t *lock = &desc->dev->msi_lock;
> + raw_spinlock_t *lock = &to_pci_dev(desc->dev)->msi_lock;
> unsigned long flags;
>
> if (!desc->pci.msi_attrib.can_mask)

It looks like most of the time this is called by an irq_chip, except
for a few special cases list pci_msi_shutdown()

Is this something that should ideally go away someday and use some
lock in the irq_chip - not unlike what we've thought is needed for
IMS?

Jason