> On 25. Sep 2019, at 06:22, Joerg Roedel <j...@8bytes.org> wrote:
>
> From: Joerg Roedel <jroe...@suse.de>
>
> The code-paths before __attach_device() and __detach_device() are called
> also access and modify domain state, so take the domain lock there too.
> This allows to get rid of the __detach_device() function.
>
> Fixes: 92d420ec028d ("iommu/amd: Relax locking in dma_ops path")
> Signed-off-by: Joerg Roedel <jroe...@suse.de>
> ---
> drivers/iommu/amd_iommu.c | 65 ++++++++++++++++-----------------------
> 1 file changed, 26 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 37a9c04fc728..2919168577ff 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -2079,27 +2079,13 @@ static void do_detach(struct iommu_dev_data *dev_data)
> static int __attach_device(struct iommu_dev_data *dev_data,
> struct protection_domain *domain)
> {
> - unsigned long flags;
> - int ret;
> -
> - /* lock domain */
> - spin_lock_irqsave(&domain->lock, flags);
> -
> - ret = -EBUSY;
> if (dev_data->domain != NULL)
> - goto out_unlock;
> + return -EBUSY;
>
> /* Attach alias group root */
> do_attach(dev_data, domain);
>
> - ret = 0;
> -
> -out_unlock:
> -
> - /* ready */
> - spin_unlock_irqrestore(&domain->lock, flags);
> -
> - return ret;
> + return 0;
> }
>
>
> @@ -2181,8 +2167,11 @@ static int attach_device(struct device *dev,
> {
> struct pci_dev *pdev;
> struct iommu_dev_data *dev_data;
> + unsigned long flags;
> int ret;
>
> + spin_lock_irqsave(&domain->lock, flags);
> +
> dev_data = get_dev_data(dev);
>
> if (!dev_is_pci(dev))
> @@ -2190,12 +2179,13 @@ static int attach_device(struct device *dev,
>
> pdev = to_pci_dev(dev);
> if (domain->flags & PD_IOMMUV2_MASK) {
> + ret = -EINVAL;
> if (!dev_data->passthrough)
> - return -EINVAL;
> + goto out;
>
> if (dev_data->iommu_v2) {
> if (pdev_iommuv2_enable(pdev) != 0)
> - return -EINVAL;
> + goto out;
>
> dev_data->ats.enabled = true;
> dev_data->ats.qdep = pci_ats_queue_depth(pdev);
> @@ -2219,24 +2209,10 @@ static int attach_device(struct device *dev,
>
> domain_flush_complete(domain);
>
> - return ret;
> -}
> -
> -/*
> - * Removes a device from a protection domain (unlocked)
> - */
> -static void __detach_device(struct iommu_dev_data *dev_data)
> -{
> - struct protection_domain *domain;
> - unsigned long flags;
> -
> - domain = dev_data->domain;
> -
> - spin_lock_irqsave(&domain->lock, flags);
> -
> - do_detach(dev_data);
> -
> +out:
> spin_unlock_irqrestore(&domain->lock, flags);
> +
> + return ret;
> }
>
> /*
> @@ -2246,10 +2222,13 @@ static void detach_device(struct device *dev)
> {
> struct protection_domain *domain;
> struct iommu_dev_data *dev_data;
> + unsigned long flags;
>
> dev_data = get_dev_data(dev);
> domain = dev_data->domain;
>
> + spin_lock_irqsave(&domain->lock, flags);
> +
> /*
> * First check if the device is still attached. It might already
> * be detached from its domain because the generic
> @@ -2257,12 +2236,12 @@ static void detach_device(struct device *dev)
> * our alias handling.
> */
> if (WARN_ON(!dev_data->domain))
> - return;
> + goto out;
>
> - __detach_device(dev_data);
> + do_detach(dev_data);
>
> if (!dev_is_pci(dev))
> - return;
> + goto out;
>
> if (domain->flags & PD_IOMMUV2_MASK && dev_data->iommu_v2)
> pdev_iommuv2_disable(to_pci_dev(dev));
> @@ -2270,6 +2249,9 @@ static void detach_device(struct device *dev)
> pci_disable_ats(to_pci_dev(dev));
>
> dev_data->ats.enabled = false;
> +
> +out:
> + spin_unlock_irqrestore(&domain->lock, flags);
> }
>
> static int amd_iommu_add_device(struct device *dev)
> @@ -2904,13 +2886,18 @@ int __init amd_iommu_init_dma_ops(void)
> static void cleanup_domain(struct protection_domain *domain)
> {
> struct iommu_dev_data *entry;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&domain->lock, flags);
>
> while (!list_empty(&domain->dev_list)) {
> entry = list_first_entry(&domain->dev_list,
> struct iommu_dev_data, list);
> BUG_ON(!entry->domain);
> - __detach_device(entry);
> + do_detach(entry);
> }
> +
> + spin_unlock_irqrestore(&domain->lock, flags);
> }
>
> static void protection_domain_free(struct protection_domain *domain)
> --
> 2.17.1
>
Reviewed-by: Filippo Sironi <sir...@amazon.de>
Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879
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