iommu/amd: Take domain->lock for complete attach/detach path

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")
Reviewed-by: Filippo Sironi <sironi@amazon.de>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 37a9c04fc728fe2cd2e1d871ba011ed40cdf2b52..2919168577ffa14eda7f16f32f4fbff8dacc843b 100644 (file)
--- 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 @@ skip_ats_check:
 
        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)