X-Git-Url: http://git.monstr.eu/?p=linux-2.6-microblaze.git;a=blobdiff_plain;f=drivers%2Fiommu%2Fintel%2Fsvm.c;h=0c228787704f36a68e5503db7330e813af4b1dac;hp=2014fe8695ace20b560f5902f49a11f926c13e43;hb=d8e988b62f948d47dd86ec655c89d54053df1754;hpb=cc09ee80c3b18ae1a897a30a17fe710b2b2f620a

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 2014fe8695ac..0c228787704f 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -514,9 +514,6 @@ static void load_pasid(struct mm_struct *mm, u32 pasid)
 {
 	mutex_lock(&mm->context.lock);
 
-	/* Synchronize with READ_ONCE in update_pasid(). */
-	smp_store_release(&mm->pasid, pasid);
-
 	/* Update PASID MSR on all CPUs running the mm's tasks. */
 	on_each_cpu_mask(mm_cpumask(mm), _load_pasid, NULL, true);
 
@@ -792,7 +789,19 @@ prq_retry:
 		goto prq_retry;
 	}
 
+	/*
+	 * A work in IO page fault workqueue may try to lock pasid_mutex now.
+	 * Holding pasid_mutex while waiting in iopf_queue_flush_dev() for
+	 * all works in the workqueue to finish may cause deadlock.
+	 *
+	 * It's unnecessary to hold pasid_mutex in iopf_queue_flush_dev().
+	 * Unlock it to allow the works to be handled while waiting for
+	 * them to finish.
+	 */
+	lockdep_assert_held(&pasid_mutex);
+	mutex_unlock(&pasid_mutex);
 	iopf_queue_flush_dev(dev);
+	mutex_lock(&pasid_mutex);
 
 	/*
 	 * Perform steps described in VT-d spec CH7.10 to drain page