1 files changed, 104 insertions, 25 deletions

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 6a33f6b1b465..67e6f83fe0f8 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -100,6 +100,7 @@ struct dmirror {
 struct dmirror_chunk {
 	struct dev_pagemap	pagemap;
 	struct dmirror_device	*mdevice;
+	bool remove;
 };
 
 /*
@@ -192,11 +193,15 @@ static int dmirror_fops_release(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static struct dmirror_chunk *dmirror_page_to_chunk(struct page *page)
+{
+	return container_of(page->pgmap, struct dmirror_chunk, pagemap);
+}
+
 static struct dmirror_device *dmirror_page_to_device(struct page *page)
 
 {
-	return container_of(page->pgmap, struct dmirror_chunk,
-			    pagemap)->mdevice;
+	return dmirror_page_to_chunk(page)->mdevice;
 }
 
 static int dmirror_do_fault(struct dmirror *dmirror, struct hmm_range *range)
@@ -627,8 +632,8 @@ static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
 			goto error;
 	}
 
+	zone_device_page_init(dpage);
 	dpage->zone_device_data = rpage;
-	lock_page(dpage);
 	return dpage;
 
 error:
@@ -907,7 +912,7 @@ static int dmirror_migrate_to_system(struct dmirror *dmirror,
 	struct vm_area_struct *vma;
 	unsigned long src_pfns[64] = { 0 };
 	unsigned long dst_pfns[64] = { 0 };
-	struct migrate_vma args;
+	struct migrate_vma args = { 0 };
 	unsigned long next;
 	int ret;
 
@@ -968,7 +973,7 @@ static int dmirror_migrate_to_device(struct dmirror *dmirror,
 	unsigned long src_pfns[64] = { 0 };
 	unsigned long dst_pfns[64] = { 0 };
 	struct dmirror_bounce bounce;
-	struct migrate_vma args;
+	struct migrate_vma args = { 0 };
 	unsigned long next;
 	int ret;
 
@@ -1218,6 +1223,85 @@ static int dmirror_snapshot(struct dmirror *dmirror,
 	return ret;
 }
 
+static void dmirror_device_evict_chunk(struct dmirror_chunk *chunk)
+{
+	unsigned long start_pfn = chunk->pagemap.range.start >> PAGE_SHIFT;
+	unsigned long end_pfn = chunk->pagemap.range.end >> PAGE_SHIFT;
+	unsigned long npages = end_pfn - start_pfn + 1;
+	unsigned long i;
+	unsigned long *src_pfns;
+	unsigned long *dst_pfns;
+
+	src_pfns = kcalloc(npages, sizeof(*src_pfns), GFP_KERNEL);
+	dst_pfns = kcalloc(npages, sizeof(*dst_pfns), GFP_KERNEL);
+
+	migrate_device_range(src_pfns, start_pfn, npages);
+	for (i = 0; i < npages; i++) {
+		struct page *dpage, *spage;
+
+		spage = migrate_pfn_to_page(src_pfns[i]);
+		if (!spage || !(src_pfns[i] & MIGRATE_PFN_MIGRATE))
+			continue;
+
+		if (WARN_ON(!is_device_private_page(spage) &&
+			    !is_device_coherent_page(spage)))
+			continue;
+		spage = BACKING_PAGE(spage);
+		dpage = alloc_page(GFP_HIGHUSER_MOVABLE | __GFP_NOFAIL);
+		lock_page(dpage);
+		copy_highpage(dpage, spage);
+		dst_pfns[i] = migrate_pfn(page_to_pfn(dpage));
+		if (src_pfns[i] & MIGRATE_PFN_WRITE)
+			dst_pfns[i] |= MIGRATE_PFN_WRITE;
+	}
+	migrate_device_pages(src_pfns, dst_pfns, npages);
+	migrate_device_finalize(src_pfns, dst_pfns, npages);
+	kfree(src_pfns);
+	kfree(dst_pfns);
+}
+
+/* Removes free pages from the free list so they can't be re-allocated */
+static void dmirror_remove_free_pages(struct dmirror_chunk *devmem)
+{
+	struct dmirror_device *mdevice = devmem->mdevice;
+	struct page *page;
+
+	for (page = mdevice->free_pages; page; page = page->zone_device_data)
+		if (dmirror_page_to_chunk(page) == devmem)
+			mdevice->free_pages = page->zone_device_data;
+}
+
+static void dmirror_device_remove_chunks(struct dmirror_device *mdevice)
+{
+	unsigned int i;
+
+	mutex_lock(&mdevice->devmem_lock);
+	if (mdevice->devmem_chunks) {
+		for (i = 0; i < mdevice->devmem_count; i++) {
+			struct dmirror_chunk *devmem =
+				mdevice->devmem_chunks[i];
+
+			spin_lock(&mdevice->lock);
+			devmem->remove = true;
+			dmirror_remove_free_pages(devmem);
+			spin_unlock(&mdevice->lock);
+
+			dmirror_device_evict_chunk(devmem);
+			memunmap_pages(&devmem->pagemap);
+			if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
+				release_mem_region(devmem->pagemap.range.start,
+						   range_len(&devmem->pagemap.range));
+			kfree(devmem);
+		}
+		mdevice->devmem_count = 0;
+		mdevice->devmem_capacity = 0;
+		mdevice->free_pages = NULL;
+		kfree(mdevice->devmem_chunks);
+		mdevice->devmem_chunks = NULL;
+	}
+	mutex_unlock(&mdevice->devmem_lock);
+}
+
 static long dmirror_fops_unlocked_ioctl(struct file *filp,
 					unsigned int command,
 					unsigned long arg)
@@ -1272,6 +1356,11 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp,
 		ret = dmirror_snapshot(dmirror, &cmd);
 		break;
 
+	case HMM_DMIRROR_RELEASE:
+		dmirror_device_remove_chunks(dmirror->mdevice);
+		ret = 0;
+		break;
+
 	default:
 		return -EINVAL;
 	}
@@ -1326,15 +1415,19 @@ static void dmirror_devmem_free(struct page *page)
 
 	mdevice = dmirror_page_to_device(page);
 	spin_lock(&mdevice->lock);
-	mdevice->cfree++;
-	page->zone_device_data = mdevice->free_pages;
-	mdevice->free_pages = page;
+
+	/* Return page to our allocator if not freeing the chunk */
+	if (!dmirror_page_to_chunk(page)->remove) {
+		mdevice->cfree++;
+		page->zone_device_data = mdevice->free_pages;
+		mdevice->free_pages = page;
+	}
 	spin_unlock(&mdevice->lock);
 }
 
 static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
 {
-	struct migrate_vma args;
+	struct migrate_vma args = { 0 };
 	unsigned long src_pfns = 0;
 	unsigned long dst_pfns = 0;
 	struct page *rpage;
@@ -1357,6 +1450,7 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
 	args.dst = &dst_pfns;
 	args.pgmap_owner = dmirror->mdevice;
 	args.flags = dmirror_select_device(dmirror);
+	args.fault_page = vmf->page;
 
 	if (migrate_vma_setup(&args))
 		return VM_FAULT_SIGBUS;
@@ -1407,22 +1501,7 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id)
 
 static void dmirror_device_remove(struct dmirror_device *mdevice)
 {
-	unsigned int i;
-
-	if (mdevice->devmem_chunks) {
-		for (i = 0; i < mdevice->devmem_count; i++) {
-			struct dmirror_chunk *devmem =
-				mdevice->devmem_chunks[i];
-
-			memunmap_pages(&devmem->pagemap);
-			if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
-				release_mem_region(devmem->pagemap.range.start,
-						   range_len(&devmem->pagemap.range));
-			kfree(devmem);
-		}
-		kfree(mdevice->devmem_chunks);
-	}
-
+	dmirror_device_remove_chunks(mdevice);
 	cdev_device_del(&mdevice->cdevice, &mdevice->device);
 }