Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "16 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/devm_memremap_pages: fix final page put race
  PCI/P2PDMA: track pgmap references per resource, not globally
  lib/genalloc: introduce chunk owners
  PCI/P2PDMA: fix the gen_pool_add_virt() failure path
  mm/devm_memremap_pages: introduce devm_memunmap_pages
  drivers/base/devres: introduce devm_release_action()
  mm/vmscan.c: fix trying to reclaim unevictable LRU page
  coredump: fix race condition between collapse_huge_page() and core dumping
  mm/mlock.c: change count_mm_mlocked_page_nr return type
  mm: mmu_gather: remove __tlb_reset_range() for force flush
  fs/ocfs2: fix race in ocfs2_dentry_attach_lock()
  mm/vmscan.c: fix recent_rotated history
  mm/mlock.c: mlockall error for flag MCL_ONFAULT
  scripts/decode_stacktrace.sh: prefix addr2line with $CROSS_COMPILE
  mm/list_lru.c: fix memory leak in __memcg_init_list_lru_node
  mm: memcontrol: don't batch updates of local VM stats and events

4 files changed, 111 insertions, 58 deletions

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index e038e2b3b7ea..0bbb328bd17f 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -755,10 +755,32 @@ void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
 
 	WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
 			       &devres));
-
 }
 EXPORT_SYMBOL_GPL(devm_remove_action);
 
+/**
+ * devm_release_action() - release previously added custom action
+ * @dev: Device that owns the action
+ * @action: Function implementing the action
+ * @data: Pointer to data passed to @action implementation
+ *
+ * Releases and removes instance of @action previously added by
+ * devm_add_action().  Both action and data should match one of the
+ * existing entries.
+ */
+void devm_release_action(struct device *dev, void (*action)(void *), void *data)
+{
+	struct action_devres devres = {
+		.data = data,
+		.action = action,
+	};
+
+	WARN_ON(devres_release(dev, devm_action_release, devm_action_match,
+			       &devres));
+
+}
+EXPORT_SYMBOL_GPL(devm_release_action);
+
 /*
  * Managed kmalloc/kfree
  */
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 996d68ff992a..8465d12fecba 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -27,9 +27,8 @@ static void dev_dax_percpu_release(struct percpu_ref *ref)
 	complete(&dev_dax->cmp);
 }
 
-static void dev_dax_percpu_exit(void *data)
+static void dev_dax_percpu_exit(struct percpu_ref *ref)
 {
-	struct percpu_ref *ref = data;
 	struct dev_dax *dev_dax = ref_to_dev_dax(ref);
 
 	dev_dbg(&dev_dax->dev, "%s\n", __func__);
@@ -466,18 +465,12 @@ int dev_dax_probe(struct device *dev)
 	if (rc)
 		return rc;
 
-	rc = devm_add_action_or_reset(dev, dev_dax_percpu_exit, &dev_dax->ref);
-	if (rc)
-		return rc;
-
 	dev_dax->pgmap.ref = &dev_dax->ref;
 	dev_dax->pgmap.kill = dev_dax_percpu_kill;
+	dev_dax->pgmap.cleanup = dev_dax_percpu_exit;
 	addr = devm_memremap_pages(dev, &dev_dax->pgmap);
-	if (IS_ERR(addr)) {
-		devm_remove_action(dev, dev_dax_percpu_exit, &dev_dax->ref);
-		percpu_ref_exit(&dev_dax->ref);
+	if (IS_ERR(addr))
 		return PTR_ERR(addr);
-	}
 
 	inode = dax_inode(dax_dev);
 	cdev = inode->i_cdev;
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 28cb44c61d4a..24d7fe7c74ed 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -303,11 +303,19 @@ static const struct attribute_group *pmem_attribute_groups[] = {
 	NULL,
 };
 
-static void pmem_release_queue(void *q)
+static void __pmem_release_queue(struct percpu_ref *ref)
 {
+	struct request_queue *q;
+
+	q = container_of(ref, typeof(*q), q_usage_counter);
 	blk_cleanup_queue(q);
 }
 
+static void pmem_release_queue(void *ref)
+{
+	__pmem_release_queue(ref);
+}
+
 static void pmem_freeze_queue(struct percpu_ref *ref)
 {
 	struct request_queue *q;
@@ -399,12 +407,10 @@ static int pmem_attach_disk(struct device *dev,
 	if (!q)
 		return -ENOMEM;
 
-	if (devm_add_action_or_reset(dev, pmem_release_queue, q))
-		return -ENOMEM;
-
 	pmem->pfn_flags = PFN_DEV;
 	pmem->pgmap.ref = &q->q_usage_counter;
 	pmem->pgmap.kill = pmem_freeze_queue;
+	pmem->pgmap.cleanup = __pmem_release_queue;
 	if (is_nd_pfn(dev)) {
 		if (setup_pagemap_fsdax(dev, &pmem->pgmap))
 			return -ENOMEM;
@@ -425,6 +431,9 @@ static int pmem_attach_disk(struct device *dev,
 		pmem->pfn_flags |= PFN_MAP;
 		memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
 	} else {
+		if (devm_add_action_or_reset(dev, pmem_release_queue,
+					&q->q_usage_counter))
+			return -ENOMEM;
 		addr = devm_memremap(dev, pmem->phys_addr,
 				pmem->size, ARCH_MEMREMAP_PMEM);
 		memcpy(&bb_res, &nsio->res, sizeof(bb_res));
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 742928d0053e..a98126ad9c3a 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -20,12 +20,16 @@
 #include <linux/seq_buf.h>
 
 struct pci_p2pdma {
-	struct percpu_ref devmap_ref;
-	struct completion devmap_ref_done;
 	struct gen_pool *pool;
 	bool p2pmem_published;
 };
 
+struct p2pdma_pagemap {
+	struct dev_pagemap pgmap;
+	struct percpu_ref ref;
+	struct completion ref_done;
+};
+
 static ssize_t size_show(struct device *dev, struct device_attribute *attr,
 			 char *buf)
 {
@@ -74,41 +78,45 @@ static const struct attribute_group p2pmem_group = {
 	.name = "p2pmem",
 };
 
+static struct p2pdma_pagemap *to_p2p_pgmap(struct percpu_ref *ref)
+{
+	return container_of(ref, struct p2pdma_pagemap, ref);
+}
+
 static void pci_p2pdma_percpu_release(struct percpu_ref *ref)
 {
-	struct pci_p2pdma *p2p =
-		container_of(ref, struct pci_p2pdma, devmap_ref);
+	struct p2pdma_pagemap *p2p_pgmap = to_p2p_pgmap(ref);
 
-	complete_all(&p2p->devmap_ref_done);
+	complete(&p2p_pgmap->ref_done);
 }
 
 static void pci_p2pdma_percpu_kill(struct percpu_ref *ref)
 {
-	/*
-	 * pci_p2pdma_add_resource() may be called multiple times
-	 * by a driver and may register the percpu_kill devm action multiple
-	 * times. We only want the first action to actually kill the
-	 * percpu_ref.
-	 */
-	if (percpu_ref_is_dying(ref))
-		return;
-
 	percpu_ref_kill(ref);
 }
 
+static void pci_p2pdma_percpu_cleanup(struct percpu_ref *ref)
+{
+	struct p2pdma_pagemap *p2p_pgmap = to_p2p_pgmap(ref);
+
+	wait_for_completion(&p2p_pgmap->ref_done);
+	percpu_ref_exit(&p2p_pgmap->ref);
+}
+
 static void pci_p2pdma_release(void *data)
 {
 	struct pci_dev *pdev = data;
+	struct pci_p2pdma *p2pdma = pdev->p2pdma;
 
-	if (!pdev->p2pdma)
+	if (!p2pdma)
 		return;
 
-	wait_for_completion(&pdev->p2pdma->devmap_ref_done);
-	percpu_ref_exit(&pdev->p2pdma->devmap_ref);
+	/* Flush and disable pci_alloc_p2p_mem() */
+	pdev->p2pdma = NULL;
+	synchronize_rcu();
 
-	gen_pool_destroy(pdev->p2pdma->pool);
+	gen_pool_destroy(p2pdma->pool);
 	sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group);
-	pdev->p2pdma = NULL;
 }
 
 static int pci_p2pdma_setup(struct pci_dev *pdev)
@@ -124,12 +132,6 @@ static int pci_p2pdma_setup(struct pci_dev *pdev)
 	if (!p2p->pool)
 		goto out;
 
-	init_completion(&p2p->devmap_ref_done);
-	error = percpu_ref_init(&p2p->devmap_ref,
-			pci_p2pdma_percpu_release, 0, GFP_KERNEL);
-	if (error)
-		goto out_pool_destroy;
-
 	error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev);
 	if (error)
 		goto out_pool_destroy;
@@ -163,6 +165,7 @@ out:
 int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
 			    u64 offset)
 {
+	struct p2pdma_pagemap *p2p_pgmap;
 	struct dev_pagemap *pgmap;
 	void *addr;
 	int error;
@@ -185,18 +188,27 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
 			return error;
 	}
 
-	pgmap = devm_kzalloc(&pdev->dev, sizeof(*pgmap), GFP_KERNEL);
-	if (!pgmap)
+	p2p_pgmap = devm_kzalloc(&pdev->dev, sizeof(*p2p_pgmap), GFP_KERNEL);
+	if (!p2p_pgmap)
 		return -ENOMEM;
 
+	init_completion(&p2p_pgmap->ref_done);
+	error = percpu_ref_init(&p2p_pgmap->ref,
+			pci_p2pdma_percpu_release, 0, GFP_KERNEL);
+	if (error)
+		goto pgmap_free;
+
+	pgmap = &p2p_pgmap->pgmap;
+
 	pgmap->res.start = pci_resource_start(pdev, bar) + offset;
 	pgmap->res.end = pgmap->res.start + size - 1;
 	pgmap->res.flags = pci_resource_flags(pdev, bar);
-	pgmap->ref = &pdev->p2pdma->devmap_ref;
+	pgmap->ref = &p2p_pgmap->ref;
 	pgmap->type = MEMORY_DEVICE_PCI_P2PDMA;
 	pgmap->pci_p2pdma_bus_offset = pci_bus_address(pdev, bar) -
 		pci_resource_start(pdev, bar);
 	pgmap->kill = pci_p2pdma_percpu_kill;
+	pgmap->cleanup = pci_p2pdma_percpu_cleanup;
 
 	addr = devm_memremap_pages(&pdev->dev, pgmap);
 	if (IS_ERR(addr)) {
@@ -204,19 +216,22 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
 		goto pgmap_free;
 	}
 
-	error = gen_pool_add_virt(pdev->p2pdma->pool, (unsigned long)addr,
+	error = gen_pool_add_owner(pdev->p2pdma->pool, (unsigned long)addr,
 			pci_bus_address(pdev, bar) + offset,
-			resource_size(&pgmap->res), dev_to_node(&pdev->dev));
+			resource_size(&pgmap->res), dev_to_node(&pdev->dev),
+			&p2p_pgmap->ref);
 	if (error)
-		goto pgmap_free;
+		goto pages_free;
 
 	pci_info(pdev, "added peer-to-peer DMA memory %pR\n",
 		 &pgmap->res);
 
 	return 0;
 
+pages_free:
+	devm_memunmap_pages(&pdev->dev, pgmap);
 pgmap_free:
-	devm_kfree(&pdev->dev, pgmap);
+	devm_kfree(&pdev->dev, p2p_pgmap);
 	return error;
 }
 EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource);
@@ -585,19 +600,30 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_find_many);
  */
 void *pci_alloc_p2pmem(struct pci_dev *pdev, size_t size)
 {
-	void *ret;
+	void *ret = NULL;
+	struct percpu_ref *ref;
 
+	/*
+	 * Pairs with synchronize_rcu() in pci_p2pdma_release() to
+	 * ensure pdev->p2pdma is non-NULL for the duration of the
+	 * read-lock.
+	 */
+	rcu_read_lock();
 	if (unlikely(!pdev->p2pdma))
-		return NULL;
-
-	if (unlikely(!percpu_ref_tryget_live(&pdev->p2pdma->devmap_ref)))
-		return NULL;
-
-	ret = (void *)gen_pool_alloc(pdev->p2pdma->pool, size);
+		goto out;
 
-	if (unlikely(!ret))
-		percpu_ref_put(&pdev->p2pdma->devmap_ref);
+	ret = (void *)gen_pool_alloc_owner(pdev->p2pdma->pool, size,
+			(void **) &ref);
+	if (!ret)
+		goto out;
 
+	if (unlikely(!percpu_ref_tryget_live(ref))) {
+		gen_pool_free(pdev->p2pdma->pool, (unsigned long) ret, size);
+		ret = NULL;
+		goto out;
+	}
+out:
+	rcu_read_unlock();
 	return ret;
 }
 EXPORT_SYMBOL_GPL(pci_alloc_p2pmem);
@@ -610,8 +636,11 @@ EXPORT_SYMBOL_GPL(pci_alloc_p2pmem);
  */
 void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size)
 {
-	gen_pool_free(pdev->p2pdma->pool, (uintptr_t)addr, size);
-	percpu_ref_put(&pdev->p2pdma->devmap_ref);
+	struct percpu_ref *ref;
+
+	gen_pool_free_owner(pdev->p2pdma->pool, (uintptr_t)addr, size,
+			(void **) &ref);
+	percpu_ref_put(ref);
 }
 EXPORT_SYMBOL_GPL(pci_free_p2pmem);