From: Peter Zijlstra Date: Tue, 3 Feb 2015 12:25:51 +0000 (+0100) Subject: iommu/amd: Fix amd_iommu_free_device() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=91f65facba5add493fffb643acdb258bd9f54eb2;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git iommu/amd: Fix amd_iommu_free_device() put_device_state_wait() doesn't loop on the condition and a spurious wakeup will have it free the device state even though there might still be references out to it. Fix this by using 'normal' wait primitives. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index 90f70d0e1141..b6398d7285f7 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -151,18 +151,6 @@ static void put_device_state(struct device_state *dev_state) wake_up(&dev_state->wq); } -static void put_device_state_wait(struct device_state *dev_state) -{ - DEFINE_WAIT(wait); - - prepare_to_wait(&dev_state->wq, &wait, TASK_UNINTERRUPTIBLE); - if (!atomic_dec_and_test(&dev_state->count)) - schedule(); - finish_wait(&dev_state->wq, &wait); - - free_device_state(dev_state); -} - /* Must be called under dev_state->lock */ static struct pasid_state **__get_pasid_state_ptr(struct device_state *dev_state, int pasid, bool alloc) @@ -851,7 +839,13 @@ void amd_iommu_free_device(struct pci_dev *pdev) /* Get rid of any remaining pasid states */ free_pasid_states(dev_state); - put_device_state_wait(dev_state); + put_device_state(dev_state); + /* + * Wait until the last reference is dropped before freeing + * the device state. + */ + wait_event(dev_state->wq, !atomic_read(&dev_state->count)); + free_device_state(dev_state); } EXPORT_SYMBOL(amd_iommu_free_device);