Merge branch 'component-for-driver' of git://ftp.arm.linux.org.uk/~rmk/linux-arm into driver-core-next

Russell writes:

These updates fix one bug in the component helper where the matched
components are not properly cleaned up when the master fails to bind.
I'll provide a version of this for stable trees if it's deemed that
we need to backport it.

The second patch causes the component helper to ignore duplicate
matches when adding components - this is something that was originally
needed for imx-drm, but since that has now been updated, we no longer
need to skip over a component which has already been matched.

The final patch starts the process of updating the component helper
API to achieve two goals: to allow the API to be more efficient when
deferred probing occurs, and to allow for future improvements to the
component helper without having a major impact on the users.

This represents groundwork for some other changes; once this has been
merged, I will then send two further pull requests (one for the staging
tree, and one for the DRM tree) to update the drivers to the new API.
This will result in these three commits being shared with those trees.

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index d4daa05efe60..499b4366a98d 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -45,7 +45,7 @@ struct pri_queue {
 struct pasid_state {
 	struct list_head list;			/* For global state-list */
 	atomic_t count;				/* Reference count */
-	atomic_t mmu_notifier_count;		/* Counting nested mmu_notifier
+	unsigned mmu_notifier_count;		/* Counting nested mmu_notifier
 						   calls */
 	struct task_struct *task;		/* Task bound to this PASID */
 	struct mm_struct *mm;			/* mm_struct for the faults */
@@ -53,7 +53,8 @@ struct pasid_state {
 	struct pri_queue pri[PRI_QUEUE_SIZE];	/* PRI tag states */
 	struct device_state *device_state;	/* Link to our device_state */
 	int pasid;				/* PASID index */
-	spinlock_t lock;			/* Protect pri_queues */
+	spinlock_t lock;			/* Protect pri_queues and
+						   mmu_notifer_count */
 	wait_queue_head_t wq;			/* To wait for count == 0 */
 };
 
@@ -431,15 +432,19 @@ static void mn_invalidate_range_start(struct mmu_notifier *mn,
 {
 	struct pasid_state *pasid_state;
 	struct device_state *dev_state;
+	unsigned long flags;
 
 	pasid_state = mn_to_state(mn);
 	dev_state   = pasid_state->device_state;
 
-	if (atomic_add_return(1, &pasid_state->mmu_notifier_count) == 1) {
+	spin_lock_irqsave(&pasid_state->lock, flags);
+	if (pasid_state->mmu_notifier_count == 0) {
 		amd_iommu_domain_set_gcr3(dev_state->domain,
 					  pasid_state->pasid,
 					  __pa(empty_page_table));
 	}
+	pasid_state->mmu_notifier_count += 1;
+	spin_unlock_irqrestore(&pasid_state->lock, flags);
 }
 
 static void mn_invalidate_range_end(struct mmu_notifier *mn,
@@ -448,15 +453,19 @@ static void mn_invalidate_range_end(struct mmu_notifier *mn,
 {
 	struct pasid_state *pasid_state;
 	struct device_state *dev_state;
+	unsigned long flags;
 
 	pasid_state = mn_to_state(mn);
 	dev_state   = pasid_state->device_state;
 
-	if (atomic_dec_and_test(&pasid_state->mmu_notifier_count)) {
+	spin_lock_irqsave(&pasid_state->lock, flags);
+	pasid_state->mmu_notifier_count -= 1;
+	if (pasid_state->mmu_notifier_count == 0) {
 		amd_iommu_domain_set_gcr3(dev_state->domain,
 					  pasid_state->pasid,
 					  __pa(pasid_state->mm->pgd));
 	}
+	spin_unlock_irqrestore(&pasid_state->lock, flags);
 }
 
 static void mn_release(struct mmu_notifier *mn, struct mm_struct *mm)
@@ -650,7 +659,6 @@ int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,
 		goto out;
 
 	atomic_set(&pasid_state->count, 1);
-	atomic_set(&pasid_state->mmu_notifier_count, 0);
 	init_waitqueue_head(&pasid_state->wq);
 	spin_lock_init(&pasid_state->lock);