xref: /kernel/linux/patches/linux-5.10/zhiyuan_patch/kernel.patch

From c31b4def60d6d4b0669aea357113f7eb87c84e67 Mon Sep 17 00:00:00 2001
From: ygopenhm <ygopenhm@vyagoo.com>
Date: Wed, 6 Jul 2022 11:13:34 +0800
Subject: [PATCH] kernel

Signed-off-by: ygopenhm <ygopenhm@vyagoo.com>
---
 Kconfig                                      |   2 +
 Makefile                                     |   2 +
 drivers/dma-buf/Kconfig                      |  24 -
 drivers/dma-buf/Makefile                     |   3 -
 drivers/dma-buf/dma-buf.c                    |  53 +-
 drivers/dma-buf/dma-heap.c                   | 223 +++++--
 drivers/dma-buf/heaps/Kconfig                |  16 +-
 drivers/dma-buf/heaps/Makefile               |   3 +-
 drivers/dma-buf/heaps/cma_heap.c             | 338 +++++++++--
 drivers/dma-buf/heaps/deferred-free-helper.c | 139 +++++
 drivers/dma-buf/heaps/deferred-free-helper.h |  57 ++
 drivers/dma-buf/heaps/heap-helpers.c         |   1 -
 drivers/dma-buf/heaps/page_pool.c            | 247 ++++++++
 drivers/dma-buf/heaps/page_pool.h            |  55 ++
 drivers/dma-buf/heaps/system_heap.c          | 576 +++++++++++++++++--
 drivers/gpu/drm/drm_gem_framebuffer_helper.c |   7 +-
 drivers/gpu/drm/drm_vblank.c                 |   2 +-
 include/linux/dma-buf.h                      |  29 +-
 include/linux/dma-heap.h                     |  62 +-
 kernel/sched/core.c                          |   3 +
 20 files changed, 1580 insertions(+), 262 deletions(-)
 create mode 100755 drivers/dma-buf/heaps/deferred-free-helper.c
 create mode 100755 drivers/dma-buf/heaps/deferred-free-helper.h
 create mode 100755 drivers/dma-buf/heaps/page_pool.c
 create mode 100755 drivers/dma-buf/heaps/page_pool.h

diff --git a/Kconfig b/Kconfig
index 745bc773f..e6c33a96d 100644
--- a/Kconfig
+++ b/Kconfig
@@ -7,6 +7,8 @@ mainmenu "Linux/$(ARCH) $(KERNELVERSION) Kernel Configuration"
 
 source "scripts/Kconfig.include"
 
+source "bsp/Kconfig"
+
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"
diff --git a/Makefile b/Makefile
index dce02fbb7..a60ed51b8 100644
--- a/Makefile
+++ b/Makefile
@@ -491,6 +491,7 @@ LINUXINCLUDE    := \
 		-I$(objtree)/arch/$(SRCARCH)/include/generated \
 		$(if $(building_out_of_srctree),-I$(srctree)/include) \
 		-I$(objtree)/include \
+		-I$(srctree)/bsp/include \
 		$(USERINCLUDE)
 
 KBUILD_AFLAGS   := -D__ASSEMBLY__ -fno-PIE
@@ -650,6 +651,7 @@ ifeq ($(KBUILD_EXTMOD),)
 # Objects we will link into vmlinux / subdirs we need to visit
 core-y		:= init/ usr/
 drivers-y	:= drivers/ sound/
+drivers-y	+= bsp/
 drivers-$(CONFIG_SAMPLES) += samples/
 drivers-y	+= net/ virt/
 libs-y		:= lib/
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index 594b77d89..3ca7de37d 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -56,19 +56,6 @@ config DMABUF_SELFTESTS
 	default n
 	depends on DMA_SHARED_BUFFER
 
-config DMABUF_PROCESS_INFO
-	bool "Show dmabuf usage of all processes"
-	default n
-	depends on DMA_SHARED_BUFFER
-	depends on PROC_FS || DEBUG_FS
-	help
-	  Choose this option to show dmabuf objects usage of all processes.
-	  Firstly, with this option, when a process creates a dmabuf object,
-	  its pid and task_comm will be recorded in the dmabuf.
-	  Secondly, this option creates dma_buf/process_bufinfo file in
-	  debugfs (if DEBUG_FS enabled) and process_dmabuf_info file in procfs
-	  (if PROC_FS enabled) to show dmabuf objects usage of all processes.
-
 menuconfig DMABUF_HEAPS
 	bool "DMA-BUF Userland Memory Heaps"
 	select DMA_SHARED_BUFFER
@@ -78,17 +65,6 @@ menuconfig DMABUF_HEAPS
 	  allows userspace to allocate dma-bufs that can be shared
 	  between drivers.
 
-menuconfig DMABUF_SYSFS_STATS
-	bool "DMA-BUF sysfs statistics"
-	depends on DMA_SHARED_BUFFER
-	help
-	   Choose this option to enable DMA-BUF sysfs statistics
-	   in location /sys/kernel/dmabuf/buffers.
-
-	   /sys/kernel/dmabuf/buffers/<inode_number> will contain
-	   statistics for the DMA-BUF with the unique inode number
-	   <inode_number>.
-
 source "drivers/dma-buf/heaps/Kconfig"
 
 endmenu
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index cfbc5e3da..995e05f60 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -6,7 +6,6 @@ obj-$(CONFIG_DMABUF_HEAPS)	+= heaps/
 obj-$(CONFIG_SYNC_FILE)		+= sync_file.o
 obj-$(CONFIG_SW_SYNC)		+= sw_sync.o sync_debug.o
 obj-$(CONFIG_UDMABUF)		+= udmabuf.o
-obj-$(CONFIG_DMABUF_SYSFS_STATS) += dma-buf-sysfs-stats.o
 
 dmabuf_selftests-y := \
 	selftest.o \
@@ -14,5 +13,3 @@ dmabuf_selftests-y := \
 	st-dma-fence-chain.o
 
 obj-$(CONFIG_DMABUF_SELFTESTS)	+= dmabuf_selftests.o
-
-obj-$(CONFIG_DMABUF_PROCESS_INFO)	+= dma-buf-process-info.o
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index b6ae42d59..922416b3a 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -29,9 +29,6 @@
 #include <uapi/linux/dma-buf.h>
 #include <uapi/linux/magic.h>
 
-#include "dma-buf-sysfs-stats.h"
-#include "dma-buf-process-info.h"
-
 static inline int is_dma_buf_file(struct file *);
 
 struct dma_buf_list {
@@ -82,7 +79,6 @@ static void dma_buf_release(struct dentry *dentry)
 	if (dmabuf->resv == (struct dma_resv *)&dmabuf[1])
 		dma_resv_fini(dmabuf->resv);
 
-	dma_buf_stats_teardown(dmabuf);
 	module_put(dmabuf->owner);
 	kfree(dmabuf->name);
 	kfree(dmabuf);
@@ -583,10 +579,6 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 	file->f_mode |= FMODE_LSEEK;
 	dmabuf->file = file;
 
-	ret = dma_buf_stats_setup(dmabuf);
-	if (ret)
-		goto err_sysfs;
-
 	mutex_init(&dmabuf->lock);
 	INIT_LIST_HEAD(&dmabuf->attachments);
 
@@ -594,17 +586,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 	list_add(&dmabuf->list_node, &db_list.head);
 	mutex_unlock(&db_list.lock);
 
-	init_dma_buf_task_info(dmabuf);
 	return dmabuf;
 
-err_sysfs:
-	/*
-	 * Set file->f_path.dentry->d_fsdata to NULL so that when
-	 * dma_buf_release() gets invoked by dentry_ops, it exits
-	 * early before calling the release() dma_buf op.
-	 */
-	file->f_path.dentry->d_fsdata = NULL;
-	fput(file);
 err_dmabuf:
 	kfree(dmabuf);
 err_module:
@@ -1304,10 +1287,8 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
 		return ret;
 
 	seq_puts(s, "\nDma-buf Objects:\n");
-	seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\t"
-		   "%-16s\t%-16s\t%-16s\n",
-		   "size", "flags", "mode", "count", "ino",
-		   "buf_name", "exp_pid",  "exp_task_comm");
+	seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n",
+		   "size", "flags", "mode", "count", "ino");
 
 	list_for_each_entry(buf_obj, &db_list.head, list_node) {
 
@@ -1315,16 +1296,13 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
 		if (ret)
 			goto error_unlock;
 
-		seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\t"
-			   "%-16d\t%-16s\n",
+		seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n",
 				buf_obj->size,
 				buf_obj->file->f_flags, buf_obj->file->f_mode,
 				file_count(buf_obj->file),
 				buf_obj->exp_name,
 				file_inode(buf_obj->file)->i_ino,
-				buf_obj->name ?: "NULL",
-				dma_buf_exp_pid(buf_obj),
-				dma_buf_exp_task_comm(buf_obj) ?: "NULL");
+				buf_obj->name ?: "");
 
 		robj = buf_obj->resv;
 		while (true) {
@@ -1405,7 +1383,6 @@ static int dma_buf_init_debugfs(void)
 		err = PTR_ERR(d);
 	}
 
-	dma_buf_process_info_init_debugfs(dma_buf_debugfs_dir);
 	return err;
 }
 
@@ -1423,27 +1400,8 @@ static inline void dma_buf_uninit_debugfs(void)
 }
 #endif
 
-#ifdef CONFIG_DMABUF_PROCESS_INFO
-struct dma_buf *get_dma_buf_from_file(struct file *f)
-{
-	if (IS_ERR_OR_NULL(f))
-		return NULL;
-
-	if (!is_dma_buf_file(f))
-		return NULL;
-
-	return f->private_data;
-}
-#endif /* CONFIG_DMABUF_PROCESS_INFO */
-
 static int __init dma_buf_init(void)
 {
-	int ret;
-
-	ret = dma_buf_init_sysfs_statistics();
-	if (ret)
-		return ret;
-
 	dma_buf_mnt = kern_mount(&dma_buf_fs_type);
 	if (IS_ERR(dma_buf_mnt))
 		return PTR_ERR(dma_buf_mnt);
@@ -1451,7 +1409,6 @@ static int __init dma_buf_init(void)
 	mutex_init(&db_list.lock);
 	INIT_LIST_HEAD(&db_list.head);
 	dma_buf_init_debugfs();
-	dma_buf_process_info_init_procfs();
 	return 0;
 }
 subsys_initcall(dma_buf_init);
@@ -1460,7 +1417,5 @@ static void __exit dma_buf_deinit(void)
 {
 	dma_buf_uninit_debugfs();
 	kern_unmount(dma_buf_mnt);
-	dma_buf_uninit_sysfs_statistics();
-	dma_buf_process_info_uninit_procfs();
 }
 __exitcall(dma_buf_deinit);
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index 70e410c64..26d59b48f 100644
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -14,6 +14,7 @@
 #include <linux/xarray.h>
 #include <linux/list.h>
 #include <linux/slab.h>
+#include <linux/nospec.h>
 #include <linux/uaccess.h>
 #include <linux/syscalls.h>
 #include <linux/dma-heap.h>
@@ -30,6 +31,7 @@
  * @heap_devt		heap device node
  * @list		list head connecting to list of heaps
  * @heap_cdev		heap char device
+ * @heap_dev		heap device struct
  *
  * Represents a heap of memory from which buffers can be made.
  */
@@ -40,6 +42,8 @@ struct dma_heap {
 	dev_t heap_devt;
 	struct list_head list;
 	struct cdev heap_cdev;
+	struct kref refcount;
+	struct device *heap_dev;
 };
 
 static LIST_HEAD(heap_list);
@@ -48,20 +52,72 @@ static dev_t dma_heap_devt;
 static struct class *dma_heap_class;
 static DEFINE_XARRAY_ALLOC(dma_heap_minors);
 
-static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
-				 unsigned int fd_flags,
-				 unsigned int heap_flags)
+struct dma_heap *dma_heap_find(const char *name)
 {
+	struct dma_heap *h;
+
+	mutex_lock(&heap_list_lock);
+	list_for_each_entry(h, &heap_list, list) {
+		if (!strcmp(h->name, name)) {
+			kref_get(&h->refcount);
+			mutex_unlock(&heap_list_lock);
+			return h;
+		}
+	}
+	mutex_unlock(&heap_list_lock);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(dma_heap_find);
+
+
+void dma_heap_buffer_free(struct dma_buf *dmabuf)
+{
+	dma_buf_put(dmabuf);
+}
+EXPORT_SYMBOL_GPL(dma_heap_buffer_free);
+
+struct dma_buf *dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
+				      unsigned int fd_flags,
+				      unsigned int heap_flags)
+{
+	if (fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
+		return ERR_PTR(-EINVAL);
+
+	if (heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
+		return ERR_PTR(-EINVAL);
 	/*
 	 * Allocations from all heaps have to begin
 	 * and end on page boundaries.
 	 */
 	len = PAGE_ALIGN(len);
 	if (!len)
-		return -EINVAL;
+		return ERR_PTR(-EINVAL);
 
 	return heap->ops->allocate(heap, len, fd_flags, heap_flags);
 }
+EXPORT_SYMBOL_GPL(dma_heap_buffer_alloc);
+
+int dma_heap_bufferfd_alloc(struct dma_heap *heap, size_t len,
+			    unsigned int fd_flags,
+			    unsigned int heap_flags)
+{
+	struct dma_buf *dmabuf;
+	int fd;
+
+	dmabuf = dma_heap_buffer_alloc(heap, len, fd_flags, heap_flags);
+
+	if (IS_ERR(dmabuf))
+		return PTR_ERR(dmabuf);
+
+	fd = dma_buf_fd(dmabuf, fd_flags);
+	if (fd < 0) {
+		dma_buf_put(dmabuf);
+		/* just return, as put will call release and that will free */
+	}
+	return fd;
+
+}
+EXPORT_SYMBOL_GPL(dma_heap_bufferfd_alloc);
 
 static int dma_heap_open(struct inode *inode, struct file *file)
 {
@@ -89,15 +145,9 @@ static long dma_heap_ioctl_allocate(struct file *file, void *data)
 	if (heap_allocation->fd)
 		return -EINVAL;
 
-	if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
-		return -EINVAL;
-
-	if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
-		return -EINVAL;
-
-	fd = dma_heap_buffer_alloc(heap, heap_allocation->len,
-				   heap_allocation->fd_flags,
-				   heap_allocation->heap_flags);
+	fd = dma_heap_bufferfd_alloc(heap, heap_allocation->len,
+				     heap_allocation->fd_flags,
+				     heap_allocation->heap_flags);
 	if (fd < 0)
 		return fd;
 
@@ -123,6 +173,7 @@ static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
 	if (nr >= ARRAY_SIZE(dma_heap_ioctl_cmds))
 		return -EINVAL;
 
+	nr = array_index_nospec(nr, ARRAY_SIZE(dma_heap_ioctl_cmds));
 	/* Get the kernel ioctl cmd that matches */
 	kcmd = dma_heap_ioctl_cmds[nr];
 
@@ -189,6 +240,47 @@ void *dma_heap_get_drvdata(struct dma_heap *heap)
 {
 	return heap->priv;
 }
+EXPORT_SYMBOL_GPL(dma_heap_get_drvdata);
+
+static void dma_heap_release(struct kref *ref)
+{
+	struct dma_heap *heap = container_of(ref, struct dma_heap, refcount);
+	int minor = MINOR(heap->heap_devt);
+
+	/* Note, we already holding the heap_list_lock here */
+	list_del(&heap->list);
+
+	device_destroy(dma_heap_class, heap->heap_devt);
+	cdev_del(&heap->heap_cdev);
+	xa_erase(&dma_heap_minors, minor);
+
+	kfree(heap);
+}
+
+void dma_heap_put(struct dma_heap *h)
+{
+	/*
+	 * Take the heap_list_lock now to avoid racing with code
+	 * scanning the list and then taking a kref.
+	 */
+	mutex_lock(&heap_list_lock);
+	kref_put(&h->refcount, dma_heap_release);
+	mutex_unlock(&heap_list_lock);
+}
+EXPORT_SYMBOL_GPL(dma_heap_put);
+
+/**
+ * dma_heap_get_dev() - get device struct for the heap
+ * @heap: DMA-Heap to retrieve device struct from
+ *
+ * Returns:
+ * The device struct for the heap.
+ */
+struct device *dma_heap_get_dev(struct dma_heap *heap)
+{
+	return heap->heap_dev;
+}
+EXPORT_SYMBOL_GPL(dma_heap_get_dev);
 
 /**
  * dma_heap_get_name() - get heap name
@@ -201,11 +293,11 @@ const char *dma_heap_get_name(struct dma_heap *heap)
 {
 	return heap->name;
 }
+EXPORT_SYMBOL_GPL(dma_heap_get_name);
 
 struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 {
-	struct dma_heap *heap, *h, *err_ret;
-	struct device *dev_ret;
+	struct dma_heap *heap, *err_ret;
 	unsigned int minor;
 	int ret;
 
@@ -220,21 +312,19 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 	}
 
 	/* check the name is unique */
-	mutex_lock(&heap_list_lock);
-	list_for_each_entry(h, &heap_list, list) {
-		if (!strcmp(h->name, exp_info->name)) {
-			mutex_unlock(&heap_list_lock);
-			pr_err("dma_heap: Already registered heap named %s\n",
-			       exp_info->name);
-			return ERR_PTR(-EINVAL);
-		}
+	heap = dma_heap_find(exp_info->name);
+	if (heap) {
+		pr_err("dma_heap: Already registered heap named %s\n",
+		       exp_info->name);
+		dma_heap_put(heap);
+		return ERR_PTR(-EINVAL);
 	}
-	mutex_unlock(&heap_list_lock);
 
 	heap = kzalloc(sizeof(*heap), GFP_KERNEL);
 	if (!heap)
 		return ERR_PTR(-ENOMEM);
 
+	kref_init(&heap->refcount);
 	heap->name = exp_info->name;
 	heap->ops = exp_info->ops;
 	heap->priv = exp_info->priv;
@@ -259,16 +349,20 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 		goto err1;
 	}
 
-	dev_ret = device_create(dma_heap_class,
-				NULL,
-				heap->heap_devt,
-				NULL,
-				heap->name);
-	if (IS_ERR(dev_ret)) {
+	heap->heap_dev = device_create(dma_heap_class,
+				       NULL,
+				       heap->heap_devt,
+				       NULL,
+				       heap->name);
+	if (IS_ERR(heap->heap_dev)) {
 		pr_err("dma_heap: Unable to create device\n");
-		err_ret = ERR_CAST(dev_ret);
+		err_ret = ERR_CAST(heap->heap_dev);
 		goto err2;
 	}
+
+	/* Make sure it doesn't disappear on us */
+	heap->heap_dev = get_device(heap->heap_dev);
+
 	/* Add heap to the list */
 	mutex_lock(&heap_list_lock);
 	list_add(&heap->list, &heap_list);
@@ -284,27 +378,88 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
 	kfree(heap);
 	return err_ret;
 }
+EXPORT_SYMBOL_GPL(dma_heap_add);
 
 static char *dma_heap_devnode(struct device *dev, umode_t *mode)
 {
 	return kasprintf(GFP_KERNEL, "dma_heap/%s", dev_name(dev));
 }
 
+static ssize_t total_pools_kb_show(struct kobject *kobj,
+				   struct kobj_attribute *attr, char *buf)
+{
+	struct dma_heap *heap;
+	u64 total_pool_size = 0;
+
+	mutex_lock(&heap_list_lock);
+	list_for_each_entry(heap, &heap_list, list) {
+		if (heap->ops->get_pool_size)
+			total_pool_size += heap->ops->get_pool_size(heap);
+	}
+	mutex_unlock(&heap_list_lock);
+
+	return sysfs_emit(buf, "%llu\n", total_pool_size / 1024);
+}
+
+static struct kobj_attribute total_pools_kb_attr =
+	__ATTR_RO(total_pools_kb);
+
+static struct attribute *dma_heap_sysfs_attrs[] = {
+	&total_pools_kb_attr.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(dma_heap_sysfs);
+
+static struct kobject *dma_heap_kobject;
+
+static int dma_heap_sysfs_setup(void)
+{
+	int ret;
+
+	dma_heap_kobject = kobject_create_and_add("dma_heap", kernel_kobj);
+	if (!dma_heap_kobject)
+		return -ENOMEM;
+
+	ret = sysfs_create_groups(dma_heap_kobject, dma_heap_sysfs_groups);
+	if (ret) {
+		kobject_put(dma_heap_kobject);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void dma_heap_sysfs_teardown(void)
+{
+	kobject_put(dma_heap_kobject);
+}
+
 static int dma_heap_init(void)
 {
 	int ret;
 
-	ret = alloc_chrdev_region(&dma_heap_devt, 0, NUM_HEAP_MINORS, DEVNAME);
+	ret = dma_heap_sysfs_setup();
 	if (ret)
 		return ret;
 
+	ret = alloc_chrdev_region(&dma_heap_devt, 0, NUM_HEAP_MINORS, DEVNAME);
+	if (ret)
+		goto err_chrdev;
+
 	dma_heap_class = class_create(THIS_MODULE, DEVNAME);
 	if (IS_ERR(dma_heap_class)) {
-		unregister_chrdev_region(dma_heap_devt, NUM_HEAP_MINORS);
-		return PTR_ERR(dma_heap_class);
+		ret = PTR_ERR(dma_heap_class);
+		goto err_class;
 	}
 	dma_heap_class->devnode = dma_heap_devnode;
 
 	return 0;
+
+err_class:
+	unregister_chrdev_region(dma_heap_devt, NUM_HEAP_MINORS);
+err_chrdev:
+	dma_heap_sysfs_teardown();
+	return ret;
 }
 subsys_initcall(dma_heap_init);
diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index a5eef06c4..ff52efa83 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -1,12 +1,22 @@
+menuconfig DMABUF_HEAPS_DEFERRED_FREE
+	bool "DMA-BUF heaps deferred-free library"
+	help
+	  Choose this option to enable the DMA-BUF heaps deferred-free library.
+
+menuconfig DMABUF_HEAPS_PAGE_POOL
+	bool "DMA-BUF heaps page-pool library"
+	help
+	  Choose this option to enable the DMA-BUF heaps page-pool library.
+
 config DMABUF_HEAPS_SYSTEM
-	bool "DMA-BUF System Heap"
-	depends on DMABUF_HEAPS
+	tristate "DMA-BUF System Heap"
+	depends on DMABUF_HEAPS && DMABUF_HEAPS_DEFERRED_FREE && DMABUF_HEAPS_PAGE_POOL
 	help
 	  Choose this option to enable the system dmabuf heap. The system heap
 	  is backed by pages from the buddy allocator. If in doubt, say Y.
 
 config DMABUF_HEAPS_CMA
-	bool "DMA-BUF CMA Heap"
+	tristate "DMA-BUF CMA Heap"
 	depends on DMABUF_HEAPS && DMA_CMA
 	help
 	  Choose this option to enable dma-buf CMA heap. This heap is backed
diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
index 6e54cdec3..4d4cd94a3 100644
--- a/drivers/dma-buf/heaps/Makefile
+++ b/drivers/dma-buf/heaps/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-y					+= heap-helpers.o
+obj-$(CONFIG_DMABUF_HEAPS_DEFERRED_FREE) += deferred-free-helper.o
+obj-$(CONFIG_DMABUF_HEAPS_PAGE_POOL)	+= page_pool.o
 obj-$(CONFIG_DMABUF_HEAPS_SYSTEM)	+= system_heap.o
 obj-$(CONFIG_DMABUF_HEAPS_CMA)		+= cma_heap.o
diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
index e55384dc1..fd564aa70 100644
--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -2,76 +2,306 @@
 /*
  * DMABUF CMA heap exporter
  *
- * Copyright (C) 2012, 2019 Linaro Ltd.
+ * Copyright (C) 2012, 2019, 2020 Linaro Ltd.
  * Author: <benjamin.gaignard@linaro.org> for ST-Ericsson.
+ *
+ * Also utilizing parts of Andrew Davis' SRAM heap:
+ * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
+ *	Andrew F. Davis <afd@ti.com>
  */
-
 #include <linux/cma.h>
-#include <linux/device.h>
 #include <linux/dma-buf.h>
 #include <linux/dma-heap.h>
 #include <linux/dma-map-ops.h>
 #include <linux/err.h>
-#include <linux/errno.h>
 #include <linux/highmem.h>
+#include <linux/io.h>
+#include <linux/mm.h>
 #include <linux/module.h>
-#include <linux/slab.h>
 #include <linux/scatterlist.h>
-#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
 
-#include "heap-helpers.h"
 
 struct cma_heap {
 	struct dma_heap *heap;
 	struct cma *cma;
 };
 
-static void cma_heap_free(struct heap_helper_buffer *buffer)
+struct cma_heap_buffer {
+	struct cma_heap *heap;
+	struct list_head attachments;
+	struct mutex lock;
+	unsigned long len;
+	struct page *cma_pages;
+	struct page **pages;
+	pgoff_t pagecount;
+	int vmap_cnt;
+	void *vaddr;
+};
+
+struct dma_heap_attachment {
+	struct device *dev;
+	struct sg_table table;
+	struct list_head list;
+	bool mapped;
+};
+
+static int cma_heap_attach(struct dma_buf *dmabuf,
+			   struct dma_buf_attachment *attachment)
+{
+	struct cma_heap_buffer *buffer = dmabuf->priv;
+	struct dma_heap_attachment *a;
+	int ret;
+
+	a = kzalloc(sizeof(*a), GFP_KERNEL);
+	if (!a)
+		return -ENOMEM;
+
+	ret = sg_alloc_table_from_pages(&a->table, buffer->pages,
+					buffer->pagecount, 0,
+					buffer->pagecount << PAGE_SHIFT,
+					GFP_KERNEL);
+	if (ret) {
+		kfree(a);
+		return ret;
+	}
+
+	a->dev = attachment->dev;
+	INIT_LIST_HEAD(&a->list);
+	a->mapped = false;
+
+	attachment->priv = a;
+
+	mutex_lock(&buffer->lock);
+	list_add(&a->list, &buffer->attachments);
+	mutex_unlock(&buffer->lock);
+
+	return 0;
+}
+
+static void cma_heap_detach(struct dma_buf *dmabuf,
+			    struct dma_buf_attachment *attachment)
+{
+	struct cma_heap_buffer *buffer = dmabuf->priv;
+	struct dma_heap_attachment *a = attachment->priv;
+
+	mutex_lock(&buffer->lock);
+	list_del(&a->list);
+	mutex_unlock(&buffer->lock);
+
+	sg_free_table(&a->table);
+	kfree(a);
+}
+
+static struct sg_table *cma_heap_map_dma_buf(struct dma_buf_attachment *attachment,
+					     enum dma_data_direction direction)
 {
-	struct cma_heap *cma_heap = dma_heap_get_drvdata(buffer->heap);
-	unsigned long nr_pages = buffer->pagecount;
-	struct page *cma_pages = buffer->priv_virt;
+	struct dma_heap_attachment *a = attachment->priv;
+	struct sg_table *table = &a->table;
+	int attrs = attachment->dma_map_attrs;
+	int ret;
+
+	ret = dma_map_sgtable(attachment->dev, table, direction, attrs);
+	if (ret)
+		return ERR_PTR(-ENOMEM);
+	a->mapped = true;
+	return table;
+}
+
+static void cma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
+				   struct sg_table *table,
+				   enum dma_data_direction direction)
+{
+	struct dma_heap_attachment *a = attachment->priv;
+	int attrs = attachment->dma_map_attrs;
+
+	a->mapped = false;
+	dma_unmap_sgtable(attachment->dev, table, direction, attrs);
+}
+
+static int cma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
+					     enum dma_data_direction direction)
+{
+	struct cma_heap_buffer *buffer = dmabuf->priv;
+	struct dma_heap_attachment *a;
+
+	if (buffer->vmap_cnt)
+		invalidate_kernel_vmap_range(buffer->vaddr, buffer->len);
+
+	mutex_lock(&buffer->lock);
+	list_for_each_entry(a, &buffer->attachments, list) {
+		if (!a->mapped)
+			continue;
+		dma_sync_sgtable_for_cpu(a->dev, &a->table, direction);
+	}
+	mutex_unlock(&buffer->lock);
+
+	return 0;
+}
+
+static int cma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
+					   enum dma_data_direction direction)
+{
+	struct cma_heap_buffer *buffer = dmabuf->priv;
+	struct dma_heap_attachment *a;
+
+	if (buffer->vmap_cnt)
+		flush_kernel_vmap_range(buffer->vaddr, buffer->len);
+
+	mutex_lock(&buffer->lock);
+	list_for_each_entry(a, &buffer->attachments, list) {
+		if (!a->mapped)
+			continue;
+		dma_sync_sgtable_for_device(a->dev, &a->table, direction);
+	}
+	mutex_unlock(&buffer->lock);
+
+	return 0;
+}
+
+static vm_fault_t cma_heap_vm_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct cma_heap_buffer *buffer = vma->vm_private_data;
+
+	if (vmf->pgoff > buffer->pagecount)
+		return VM_FAULT_SIGBUS;
+
+	vmf->page = buffer->pages[vmf->pgoff];
+	get_page(vmf->page);
+
+	return 0;
+}
+
+static const struct vm_operations_struct dma_heap_vm_ops = {
+	.fault = cma_heap_vm_fault,
+};
+
+static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
+{
+	struct cma_heap_buffer *buffer = dmabuf->priv;
+
+	if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
+		return -EINVAL;
+
+	vma->vm_ops = &dma_heap_vm_ops;
+	vma->vm_private_data = buffer;
+
+	return 0;
+}
+
+static void *cma_heap_do_vmap(struct cma_heap_buffer *buffer)
+{
+	void *vaddr;
+
+	vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL);
+	if (!vaddr)
+		return ERR_PTR(-ENOMEM);
+
+	return vaddr;
+}
+
+static void *cma_heap_vmap(struct dma_buf *dmabuf)
+{
+	struct cma_heap_buffer *buffer = dmabuf->priv;
+	void *vaddr;
+
+	mutex_lock(&buffer->lock);
+	if (buffer->vmap_cnt) {
+		buffer->vmap_cnt++;
+		vaddr = buffer->vaddr;
+		goto out;
+	}
+
+	vaddr = cma_heap_do_vmap(buffer);
+	if (IS_ERR(vaddr))
+		goto out;
+
+	buffer->vaddr = vaddr;
+	buffer->vmap_cnt++;
+out:
+	mutex_unlock(&buffer->lock);
+
+	return vaddr;
+}
+
+static void cma_heap_vunmap(struct dma_buf *dmabuf, void *vaddr)
+{
+	struct cma_heap_buffer *buffer = dmabuf->priv;
+
+	mutex_lock(&buffer->lock);
+	if (!--buffer->vmap_cnt) {
+		vunmap(buffer->vaddr);
+		buffer->vaddr = NULL;
+	}
+	mutex_unlock(&buffer->lock);
+}
+
+static void cma_heap_dma_buf_release(struct dma_buf *dmabuf)
+{
+	struct cma_heap_buffer *buffer = dmabuf->priv;
+	struct cma_heap *cma_heap = buffer->heap;
+
+	if (buffer->vmap_cnt > 0) {
+		WARN(1, "%s: buffer still mapped in the kernel\n", __func__);
+		vunmap(buffer->vaddr);
+	}
 
 	/* free page list */
 	kfree(buffer->pages);
 	/* release memory */
-	cma_release(cma_heap->cma, cma_pages, nr_pages);
+	cma_release(cma_heap->cma, buffer->cma_pages, buffer->pagecount);
 	kfree(buffer);
 }
 
-/* dmabuf heap CMA operations functions */
-static int cma_heap_allocate(struct dma_heap *heap,
-			     unsigned long len,
-			     unsigned long fd_flags,
-			     unsigned long heap_flags)
+static const struct dma_buf_ops cma_heap_buf_ops = {
+	.attach = cma_heap_attach,
+	.detach = cma_heap_detach,
+	.map_dma_buf = cma_heap_map_dma_buf,
+	.unmap_dma_buf = cma_heap_unmap_dma_buf,
+	.begin_cpu_access = cma_heap_dma_buf_begin_cpu_access,
+	.end_cpu_access = cma_heap_dma_buf_end_cpu_access,
+	.mmap = cma_heap_mmap,
+	.vmap = cma_heap_vmap,
+	.vunmap = cma_heap_vunmap,
+	.release = cma_heap_dma_buf_release,
+};
+
+static struct dma_buf *cma_heap_allocate(struct dma_heap *heap,
+					 unsigned long len,
+					 unsigned long fd_flags,
+					 unsigned long heap_flags)
 {
 	struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
-	struct heap_helper_buffer *helper_buffer;
-	struct page *cma_pages;
+	struct cma_heap_buffer *buffer;
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 	size_t size = PAGE_ALIGN(len);
-	unsigned long nr_pages = size >> PAGE_SHIFT;
+	pgoff_t pagecount = size >> PAGE_SHIFT;
 	unsigned long align = get_order(size);
+	struct page *cma_pages;
 	struct dma_buf *dmabuf;
 	int ret = -ENOMEM;
 	pgoff_t pg;
 
-	if (align > CONFIG_CMA_ALIGNMENT)
-		align = CONFIG_CMA_ALIGNMENT;
+	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+	if (!buffer)
+		return ERR_PTR(-ENOMEM);
 
-	helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
-	if (!helper_buffer)
-		return -ENOMEM;
+	INIT_LIST_HEAD(&buffer->attachments);
+	mutex_init(&buffer->lock);
+	buffer->len = size;
 
-	init_heap_helper_buffer(helper_buffer, cma_heap_free);
-	helper_buffer->heap = heap;
-	helper_buffer->size = len;
+	if (align > CONFIG_CMA_ALIGNMENT)
+		align = CONFIG_CMA_ALIGNMENT;
 
-	cma_pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
+	cma_pages = cma_alloc(cma_heap->cma, pagecount, align, GFP_KERNEL);
 	if (!cma_pages)
-		goto free_buf;
+		goto free_buffer;
 
+	/* Clear the cma pages */
 	if (PageHighMem(cma_pages)) {
-		unsigned long nr_clear_pages = nr_pages;
+		unsigned long nr_clear_pages = pagecount;
 		struct page *page = cma_pages;
 
 		while (nr_clear_pages > 0) {
@@ -85,7 +315,6 @@ static int cma_heap_allocate(struct dma_heap *heap,
 			 */
 			if (fatal_signal_pending(current))
 				goto free_cma;
-
 			page++;
 			nr_clear_pages--;
 		}
@@ -93,44 +322,41 @@ static int cma_heap_allocate(struct dma_heap *heap,
 		memset(page_address(cma_pages), 0, size);
 	}
 
-	helper_buffer->pagecount = nr_pages;
-	helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
-					     sizeof(*helper_buffer->pages),
-					     GFP_KERNEL);
-	if (!helper_buffer->pages) {
+	buffer->pages = kmalloc_array(pagecount, sizeof(*buffer->pages), GFP_KERNEL);
+	if (!buffer->pages) {
 		ret = -ENOMEM;
 		goto free_cma;
 	}
 
-	for (pg = 0; pg < helper_buffer->pagecount; pg++)
-		helper_buffer->pages[pg] = &cma_pages[pg];
+	for (pg = 0; pg < pagecount; pg++)
+		buffer->pages[pg] = &cma_pages[pg];
+
+	buffer->cma_pages = cma_pages;
+	buffer->heap = cma_heap;
+	buffer->pagecount = pagecount;
 
 	/* create the dmabuf */
-	dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
+	exp_info.exp_name = dma_heap_get_name(heap);
+	exp_info.ops = &cma_heap_buf_ops;
+	exp_info.size = buffer->len;
+	exp_info.flags = fd_flags;
+	exp_info.priv = buffer;
+	dmabuf = dma_buf_export(&exp_info);
 	if (IS_ERR(dmabuf)) {
 		ret = PTR_ERR(dmabuf);
 		goto free_pages;
 	}
 
-	helper_buffer->dmabuf = dmabuf;
-	helper_buffer->priv_virt = cma_pages;
-
-	ret = dma_buf_fd(dmabuf, fd_flags);
-	if (ret < 0) {
-		dma_buf_put(dmabuf);
-		/* just return, as put will call release and that will free */
-		return ret;
-	}
-
-	return ret;
+	return dmabuf;
 
 free_pages:
-	kfree(helper_buffer->pages);
+	kfree(buffer->pages);
 free_cma:
-	cma_release(cma_heap->cma, cma_pages, nr_pages);
-free_buf:
-	kfree(helper_buffer);
-	return ret;
+	cma_release(cma_heap->cma, cma_pages, pagecount);
+free_buffer:
+	kfree(buffer);
+
+	return ERR_PTR(ret);
 }
 
 static const struct dma_heap_ops cma_heap_ops = {
diff --git a/drivers/dma-buf/heaps/deferred-free-helper.c b/drivers/dma-buf/heaps/deferred-free-helper.c
new file mode 100755
index 000000000..1330d279f
--- /dev/null
+++ b/drivers/dma-buf/heaps/deferred-free-helper.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Deferred dmabuf freeing helper
+ *
+ * Copyright (C) 2020 Linaro, Ltd.
+ *
+ * Based on the ION page pool code
+ * Copyright (C) 2011 Google, Inc.
+ */
+
+#include <linux/freezer.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/sched/signal.h>
+
+#include "deferred-free-helper.h"
+
+static LIST_HEAD(free_list);
+static size_t list_nr_pages;
+wait_queue_head_t freelist_waitqueue;
+struct task_struct *freelist_task;
+static DEFINE_SPINLOCK(free_list_lock);
+
+void deferred_free(struct deferred_freelist_item *item,
+		   void (*free)(struct deferred_freelist_item*,
+				enum df_reason),
+		   size_t nr_pages)
+{
+	unsigned long flags;
+
+	INIT_LIST_HEAD(&item->list);
+	item->nr_pages = nr_pages;
+	item->free = free;
+
+	spin_lock_irqsave(&free_list_lock, flags);
+	list_add(&item->list, &free_list);
+	list_nr_pages += nr_pages;
+	spin_unlock_irqrestore(&free_list_lock, flags);
+	wake_up(&freelist_waitqueue);
+}
+EXPORT_SYMBOL_GPL(deferred_free);
+
+static size_t free_one_item(enum df_reason reason)
+{
+	unsigned long flags;
+	size_t nr_pages;
+	struct deferred_freelist_item *item;
+
+	spin_lock_irqsave(&free_list_lock, flags);
+	if (list_empty(&free_list)) {
+		spin_unlock_irqrestore(&free_list_lock, flags);
+		return 0;
+	}
+	item = list_first_entry(&free_list, struct deferred_freelist_item, list);
+	list_del(&item->list);
+	nr_pages = item->nr_pages;
+	list_nr_pages -= nr_pages;
+	spin_unlock_irqrestore(&free_list_lock, flags);
+
+	item->free(item, reason);
+	return nr_pages;
+}
+
+unsigned long get_freelist_nr_pages(void)
+{
+	unsigned long nr_pages;
+	unsigned long flags;
+
+	spin_lock_irqsave(&free_list_lock, flags);
+	nr_pages = list_nr_pages;
+	spin_unlock_irqrestore(&free_list_lock, flags);
+	return nr_pages;
+}
+EXPORT_SYMBOL_GPL(get_freelist_nr_pages);
+
+static unsigned long freelist_shrink_count(struct shrinker *shrinker,
+					   struct shrink_control *sc)
+{
+	return get_freelist_nr_pages();
+}
+
+static unsigned long freelist_shrink_scan(struct shrinker *shrinker,
+					  struct shrink_control *sc)
+{
+	unsigned long total_freed = 0;
+
+	if (sc->nr_to_scan == 0)
+		return 0;
+
+	while (total_freed < sc->nr_to_scan) {
+		size_t pages_freed = free_one_item(DF_UNDER_PRESSURE);
+
+		if (!pages_freed)
+			break;
+
+		total_freed += pages_freed;
+	}
+
+	return total_freed;
+}
+
+static struct shrinker freelist_shrinker = {
+	.count_objects = freelist_shrink_count,
+	.scan_objects = freelist_shrink_scan,
+	.seeks = DEFAULT_SEEKS,
+	.batch = 0,
+};
+
+static int deferred_free_thread(void *data)
+{
+	while (true) {
+		wait_event_freezable(freelist_waitqueue,
+				     get_freelist_nr_pages() > 0);
+
+		free_one_item(DF_NORMAL);
+	}
+
+	return 0;
+}
+
+static int deferred_freelist_init(void)
+{
+	list_nr_pages = 0;
+
+	init_waitqueue_head(&freelist_waitqueue);
+	freelist_task = kthread_run(deferred_free_thread, NULL,
+				    "%s", "dmabuf-deferred-free-worker");
+	if (IS_ERR(freelist_task)) {
+		pr_err("Creating thread for deferred free failed\n");
+		return -1;
+	}
+	sched_set_normal(freelist_task, 19);
+
+	return register_shrinker(&freelist_shrinker);
+}
+module_init(deferred_freelist_init);
+MODULE_LICENSE("GPL v2");
+
diff --git a/drivers/dma-buf/heaps/deferred-free-helper.h b/drivers/dma-buf/heaps/deferred-free-helper.h
new file mode 100755
index 000000000..415440314
--- /dev/null
+++ b/drivers/dma-buf/heaps/deferred-free-helper.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef DEFERRED_FREE_HELPER_H
+#define DEFERRED_FREE_HELPER_H
+
+/**
+ * df_reason - enum for reason why item was freed
+ *
+ * This provides a reason for why the free function was called
+ * on the item. This is useful when deferred_free is used in
+ * combination with a pagepool, so under pressure the page can
+ * be immediately freed.
+ *
+ * DF_NORMAL:         Normal deferred free
+ *
+ * DF_UNDER_PRESSURE: Free was called because the system
+ *                    is under memory pressure. Usually
+ *                    from a shrinker. Avoid allocating
+ *                    memory in the free call, as it may
+ *                    fail.
+ */
+enum df_reason {
+	DF_NORMAL,
+	DF_UNDER_PRESSURE,
+};
+
+/**
+ * deferred_freelist_item - item structure for deferred freelist
+ *
+ * This is to be added to the structure for whatever you want to
+ * defer freeing on.
+ *
+ * @nr_pages: number of pages used by item to be freed
+ * @free: function pointer to be called when freeing the item
+ * @list: list entry for the deferred list
+ */
+struct deferred_freelist_item {
+	size_t nr_pages;
+	void (*free)(struct deferred_freelist_item *i,
+		     enum df_reason reason);
+	struct list_head list;
+};
+
+/**
+ * deferred_free - call to add item to the deferred free list
+ *
+ * @item: Pointer to deferred_freelist_item field of a structure
+ * @free: Function pointer to the free call
+ * @nr_pages: number of pages to be freed
+ */
+void deferred_free(struct deferred_freelist_item *item,
+		   void (*free)(struct deferred_freelist_item *i,
+				enum df_reason reason),
+		   size_t nr_pages);
+
+unsigned long get_freelist_nr_pages(void);
+#endif
diff --git a/drivers/dma-buf/heaps/heap-helpers.c b/drivers/dma-buf/heaps/heap-helpers.c
index 35aa65bbf..d0696cf93 100644
--- a/drivers/dma-buf/heaps/heap-helpers.c
+++ b/drivers/dma-buf/heaps/heap-helpers.c
@@ -30,7 +30,6 @@ struct dma_buf *heap_helper_export_dmabuf(struct heap_helper_buffer *buffer,
 {
 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 
-	exp_info.exp_name = dma_heap_get_name(buffer->heap);
 	exp_info.ops = &heap_helper_ops;
 	exp_info.size = buffer->size;
 	exp_info.flags = fd_flags;
diff --git a/drivers/dma-buf/heaps/page_pool.c b/drivers/dma-buf/heaps/page_pool.c
new file mode 100755
index 000000000..b79e737ba
--- /dev/null
+++ b/drivers/dma-buf/heaps/page_pool.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DMA BUF page pool system
+ *
+ * Copyright (C) 2020 Linaro Ltd.
+ *
+ * Based on the ION page pool code
+ * Copyright (C) 2011 Google, Inc.
+ */
+
+#include <linux/freezer.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/sched/signal.h>
+#include "page_pool.h"
+
+static LIST_HEAD(pool_list);
+static DEFINE_MUTEX(pool_list_lock);
+
+static inline
+struct page *dmabuf_page_pool_alloc_pages(struct dmabuf_page_pool *pool)
+{
+	if (fatal_signal_pending(current))
+		return NULL;
+	return alloc_pages(pool->gfp_mask, pool->order);
+}
+
+static inline void dmabuf_page_pool_free_pages(struct dmabuf_page_pool *pool,
+					       struct page *page)
+{
+	__free_pages(page, pool->order);
+}
+
+static void dmabuf_page_pool_add(struct dmabuf_page_pool *pool, struct page *page)
+{
+	int index;
+
+	if (PageHighMem(page))
+		index = POOL_HIGHPAGE;
+	else
+		index = POOL_LOWPAGE;
+
+	mutex_lock(&pool->mutex);
+	list_add_tail(&page->lru, &pool->items[index]);
+	pool->count[index]++;
+	mod_node_page_state(page_pgdat(page), NR_KERNEL_MISC_RECLAIMABLE,
+			    1 << pool->order);
+	mutex_unlock(&pool->mutex);
+}
+
+static struct page *dmabuf_page_pool_remove(struct dmabuf_page_pool *pool, int index)
+{
+	struct page *page;
+
+	mutex_lock(&pool->mutex);
+	page = list_first_entry_or_null(&pool->items[index], struct page, lru);
+	if (page) {
+		pool->count[index]--;
+		list_del(&page->lru);
+		mod_node_page_state(page_pgdat(page), NR_KERNEL_MISC_RECLAIMABLE,
+				    -(1 << pool->order));
+	}
+	mutex_unlock(&pool->mutex);
+
+	return page;
+}
+
+static struct page *dmabuf_page_pool_fetch(struct dmabuf_page_pool *pool)
+{
+	struct page *page = NULL;
+
+	page = dmabuf_page_pool_remove(pool, POOL_HIGHPAGE);
+	if (!page)
+		page = dmabuf_page_pool_remove(pool, POOL_LOWPAGE);
+
+	return page;
+}
+
+struct page *dmabuf_page_pool_alloc(struct dmabuf_page_pool *pool)
+{
+	struct page *page = NULL;
+
+	if (WARN_ON(!pool))
+		return NULL;
+
+	page = dmabuf_page_pool_fetch(pool);
+
+	if (!page)
+		page = dmabuf_page_pool_alloc_pages(pool);
+	return page;
+}
+EXPORT_SYMBOL_GPL(dmabuf_page_pool_alloc);
+
+void dmabuf_page_pool_free(struct dmabuf_page_pool *pool, struct page *page)
+{
+	if (WARN_ON(pool->order != compound_order(page)))
+		return;
+
+	dmabuf_page_pool_add(pool, page);
+}
+EXPORT_SYMBOL_GPL(dmabuf_page_pool_free);
+
+static int dmabuf_page_pool_total(struct dmabuf_page_pool *pool, bool high)
+{
+	int count = pool->count[POOL_LOWPAGE];
+
+	if (high)
+		count += pool->count[POOL_HIGHPAGE];
+
+	return count << pool->order;
+}
+
+struct dmabuf_page_pool *dmabuf_page_pool_create(gfp_t gfp_mask, unsigned int order)
+{
+	struct dmabuf_page_pool *pool = kmalloc(sizeof(*pool), GFP_KERNEL);
+	int i;
+
+	if (!pool)
+		return NULL;
+
+	for (i = 0; i < POOL_TYPE_SIZE; i++) {
+		pool->count[i] = 0;
+		INIT_LIST_HEAD(&pool->items[i]);
+	}
+	pool->gfp_mask = gfp_mask | __GFP_COMP;
+	pool->order = order;
+	mutex_init(&pool->mutex);
+
+	mutex_lock(&pool_list_lock);
+	list_add(&pool->list, &pool_list);
+	mutex_unlock(&pool_list_lock);
+
+	return pool;
+}
+EXPORT_SYMBOL_GPL(dmabuf_page_pool_create);
+
+void dmabuf_page_pool_destroy(struct dmabuf_page_pool *pool)
+{
+	struct page *page;
+	int i;
+
+	/* Remove us from the pool list */
+	mutex_lock(&pool_list_lock);
+	list_del(&pool->list);
+	mutex_unlock(&pool_list_lock);
+
+	/* Free any remaining pages in the pool */
+	for (i = 0; i < POOL_TYPE_SIZE; i++) {
+		while ((page = dmabuf_page_pool_remove(pool, i)))
+			dmabuf_page_pool_free_pages(pool, page);
+	}
+
+	kfree(pool);
+}
+EXPORT_SYMBOL_GPL(dmabuf_page_pool_destroy);
+
+static int dmabuf_page_pool_do_shrink(struct dmabuf_page_pool *pool, gfp_t gfp_mask,
+				      int nr_to_scan)
+{
+	int freed = 0;
+	bool high;
+
+	if (current_is_kswapd())
+		high = true;
+	else
+		high = !!(gfp_mask & __GFP_HIGHMEM);
+
+	if (nr_to_scan == 0)
+		return dmabuf_page_pool_total(pool, high);
+
+	while (freed < nr_to_scan) {
+		struct page *page;
+
+		/* Try to free low pages first */
+		page = dmabuf_page_pool_remove(pool, POOL_LOWPAGE);
+		if (!page)
+			page = dmabuf_page_pool_remove(pool, POOL_HIGHPAGE);
+
+		if (!page)
+			break;
+
+		dmabuf_page_pool_free_pages(pool, page);
+		freed += (1 << pool->order);
+	}
+
+	return freed;
+}
+
+static int dmabuf_page_pool_shrink(gfp_t gfp_mask, int nr_to_scan)
+{
+	struct dmabuf_page_pool *pool;
+	int nr_total = 0;
+	int nr_freed;
+	int only_scan = 0;
+
+	if (!nr_to_scan)
+		only_scan = 1;
+
+	mutex_lock(&pool_list_lock);
+	list_for_each_entry(pool, &pool_list, list) {
+		if (only_scan) {
+			nr_total += dmabuf_page_pool_do_shrink(pool,
+							       gfp_mask,
+							       nr_to_scan);
+		} else {
+			nr_freed = dmabuf_page_pool_do_shrink(pool,
+							      gfp_mask,
+							      nr_to_scan);
+			nr_to_scan -= nr_freed;
+			nr_total += nr_freed;
+			if (nr_to_scan <= 0)
+				break;
+		}
+	}
+	mutex_unlock(&pool_list_lock);
+
+	return nr_total;
+}
+
+static unsigned long dmabuf_page_pool_shrink_count(struct shrinker *shrinker,
+						   struct shrink_control *sc)
+{
+	return dmabuf_page_pool_shrink(sc->gfp_mask, 0);
+}
+
+static unsigned long dmabuf_page_pool_shrink_scan(struct shrinker *shrinker,
+						  struct shrink_control *sc)
+{
+	if (sc->nr_to_scan == 0)
+		return 0;
+	return dmabuf_page_pool_shrink(sc->gfp_mask, sc->nr_to_scan);
+}
+
+struct shrinker pool_shrinker = {
+	.count_objects = dmabuf_page_pool_shrink_count,
+	.scan_objects = dmabuf_page_pool_shrink_scan,
+	.seeks = DEFAULT_SEEKS,
+	.batch = 0,
+};
+
+static int dmabuf_page_pool_init_shrinker(void)
+{
+	return register_shrinker(&pool_shrinker);
+}
+module_init(dmabuf_page_pool_init_shrinker);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/dma-buf/heaps/page_pool.h b/drivers/dma-buf/heaps/page_pool.h
new file mode 100755
index 000000000..6b083b04f
--- /dev/null
+++ b/drivers/dma-buf/heaps/page_pool.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * DMA BUF PagePool implementation
+ * Based on earlier ION code by Google
+ *
+ * Copyright (C) 2011 Google, Inc.
+ * Copyright (C) 2020 Linaro Ltd.
+ */
+
+#ifndef _DMABUF_PAGE_POOL_H
+#define _DMABUF_PAGE_POOL_H
+
+#include <linux/device.h>
+#include <linux/kref.h>
+#include <linux/mm_types.h>
+#include <linux/mutex.h>
+#include <linux/shrinker.h>
+#include <linux/types.h>
+
+/* page types we track in the pool */
+enum {
+	POOL_LOWPAGE,      /* Clean lowmem pages */
+	POOL_HIGHPAGE,     /* Clean highmem pages */
+
+	POOL_TYPE_SIZE,
+};
+
+/**
+ * struct dmabuf_page_pool - pagepool struct
+ * @count[]:		array of number of pages of that type in the pool
+ * @items[]:		array of list of pages of the specific type
+ * @mutex:		lock protecting this struct and especially the count
+ *			item list
+ * @gfp_mask:		gfp_mask to use from alloc
+ * @order:		order of pages in the pool
+ * @list:		list node for list of pools
+ *
+ * Allows you to keep a pool of pre allocated pages to use
+ */
+struct dmabuf_page_pool {
+	int count[POOL_TYPE_SIZE];
+	struct list_head items[POOL_TYPE_SIZE];
+	struct mutex mutex;
+	gfp_t gfp_mask;
+	unsigned int order;
+	struct list_head list;
+};
+
+struct dmabuf_page_pool *dmabuf_page_pool_create(gfp_t gfp_mask,
+						 unsigned int order);
+void dmabuf_page_pool_destroy(struct dmabuf_page_pool *pool);
+struct page *dmabuf_page_pool_alloc(struct dmabuf_page_pool *pool);
+void dmabuf_page_pool_free(struct dmabuf_page_pool *pool, struct page *page);
+
+#endif /* _DMABUF_PAGE_POOL_H */
diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index 0bf688e3c..bbca2e195 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -3,7 +3,11 @@
  * DMABUF System heap exporter
  *
  * Copyright (C) 2011 Google, Inc.
- * Copyright (C) 2019 Linaro Ltd.
+ * Copyright (C) 2019, 2020 Linaro Ltd.
+ *
+ * Portions based off of Andrew Davis' SRAM heap:
+ * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
+ *	Andrew F. Davis <afd@ti.com>
  */
 
 #include <linux/dma-buf.h>
@@ -15,99 +19,547 @@
 #include <linux/module.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
-#include <linux/sched/signal.h>
-#include <asm/page.h>
+#include <linux/vmalloc.h>
+
+#include "page_pool.h"
+#include "deferred-free-helper.h"
+
+static struct dma_heap *sys_heap;
+static struct dma_heap *sys_uncached_heap;
+
+struct system_heap_buffer {
+	struct dma_heap *heap;
+	struct list_head attachments;
+	struct mutex lock;
+	unsigned long len;
+	struct sg_table sg_table;
+	int vmap_cnt;
+	void *vaddr;
+	struct deferred_freelist_item deferred_free;
+
+	bool uncached;
+};
+
+struct dma_heap_attachment {
+	struct device *dev;
+	struct sg_table *table;
+	struct list_head list;
+	bool mapped;
 
-#include "heap-helpers.h"
+	bool uncached;
+};
 
-struct dma_heap *sys_heap;
+#define LOW_ORDER_GFP (GFP_HIGHUSER | __GFP_ZERO | __GFP_COMP)
+#define MID_ORDER_GFP (LOW_ORDER_GFP | __GFP_NOWARN)
+#define HIGH_ORDER_GFP  (((GFP_HIGHUSER | __GFP_ZERO | __GFP_NOWARN \
+				| __GFP_NORETRY) & ~__GFP_RECLAIM) \
+				| __GFP_COMP)
+static gfp_t order_flags[] = {HIGH_ORDER_GFP, MID_ORDER_GFP, LOW_ORDER_GFP};
+/*
+ * The selection of the orders used for allocation (1MB, 64K, 4K) is designed
+ * to match with the sizes often found in IOMMUs. Using order 4 pages instead
+ * of order 0 pages can significantly improve the performance of many IOMMUs
+ * by reducing TLB pressure and time spent updating page tables.
+ */
+static const unsigned int orders[] = {8, 4, 0};
+#define NUM_ORDERS ARRAY_SIZE(orders)
+struct dmabuf_page_pool *pools[NUM_ORDERS];
 
-static void system_heap_free(struct heap_helper_buffer *buffer)
+static struct sg_table *dup_sg_table(struct sg_table *table)
 {
-	pgoff_t pg;
+	struct sg_table *new_table;
+	int ret, i;
+	struct scatterlist *sg, *new_sg;
 
-	for (pg = 0; pg < buffer->pagecount; pg++)
-		__free_page(buffer->pages[pg]);
-	kfree(buffer->pages);
-	kfree(buffer);
+	new_table = kzalloc(sizeof(*new_table), GFP_KERNEL);
+	if (!new_table)
+		return ERR_PTR(-ENOMEM);
+
+	ret = sg_alloc_table(new_table, table->orig_nents, GFP_KERNEL);
+	if (ret) {
+		kfree(new_table);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	new_sg = new_table->sgl;
+	for_each_sgtable_sg(table, sg, i) {
+		sg_set_page(new_sg, sg_page(sg), sg->length, sg->offset);
+		new_sg = sg_next(new_sg);
+	}
+
+	return new_table;
 }
 
-static int system_heap_allocate(struct dma_heap *heap,
-				unsigned long len,
-				unsigned long fd_flags,
-				unsigned long heap_flags)
+static int system_heap_attach(struct dma_buf *dmabuf,
+			      struct dma_buf_attachment *attachment)
 {
-	struct heap_helper_buffer *helper_buffer;
-	struct dma_buf *dmabuf;
-	int ret = -ENOMEM;
-	pgoff_t pg;
+	struct system_heap_buffer *buffer = dmabuf->priv;
+	struct dma_heap_attachment *a;
+	struct sg_table *table;
+
+	a = kzalloc(sizeof(*a), GFP_KERNEL);
+	if (!a)
+		return -ENOMEM;
 
-	helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
-	if (!helper_buffer)
+	table = dup_sg_table(&buffer->sg_table);
+	if (IS_ERR(table)) {
+		kfree(a);
 		return -ENOMEM;
+	}
+
+	a->table = table;
+	a->dev = attachment->dev;
+	INIT_LIST_HEAD(&a->list);
+	a->mapped = false;
+	a->uncached = buffer->uncached;
+	attachment->priv = a;
+
+	mutex_lock(&buffer->lock);
+	list_add(&a->list, &buffer->attachments);
+	mutex_unlock(&buffer->lock);
+
+	return 0;
+}
+
+static void system_heap_detach(struct dma_buf *dmabuf,
+			       struct dma_buf_attachment *attachment)
+{
+	struct system_heap_buffer *buffer = dmabuf->priv;
+	struct dma_heap_attachment *a = attachment->priv;
+
+	mutex_lock(&buffer->lock);
+	list_del(&a->list);
+	mutex_unlock(&buffer->lock);
+
+	sg_free_table(a->table);
+	kfree(a->table);
+	kfree(a);
+}
 
-	init_heap_helper_buffer(helper_buffer, system_heap_free);
-	helper_buffer->heap = heap;
-	helper_buffer->size = len;
+static struct sg_table *system_heap_map_dma_buf(struct dma_buf_attachment *attachment,
+						enum dma_data_direction direction)
+{
+	struct dma_heap_attachment *a = attachment->priv;
+	struct sg_table *table = a->table;
+	int attr = attachment->dma_map_attrs;
+	int ret;
+
+	if (a->uncached)
+		attr |= DMA_ATTR_SKIP_CPU_SYNC;
+
+	ret = dma_map_sgtable(attachment->dev, table, direction, attr);
+	if (ret)
+		return ERR_PTR(ret);
+
+	a->mapped = true;
+	return table;
+}
+
+static void system_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
+				      struct sg_table *table,
+				      enum dma_data_direction direction)
+{
+	struct dma_heap_attachment *a = attachment->priv;
+	int attr = attachment->dma_map_attrs;
+
+	if (a->uncached)
+		attr |= DMA_ATTR_SKIP_CPU_SYNC;
+	a->mapped = false;
+	dma_unmap_sgtable(attachment->dev, table, direction, attr);
+}
 
-	helper_buffer->pagecount = len / PAGE_SIZE;
-	helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
-					     sizeof(*helper_buffer->pages),
-					     GFP_KERNEL);
-	if (!helper_buffer->pages) {
-		ret = -ENOMEM;
-		goto err0;
+static int system_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
+						enum dma_data_direction direction)
+{
+	struct system_heap_buffer *buffer = dmabuf->priv;
+	struct dma_heap_attachment *a;
+
+	mutex_lock(&buffer->lock);
+
+	if (buffer->vmap_cnt)
+		invalidate_kernel_vmap_range(buffer->vaddr, buffer->len);
+
+	if (!buffer->uncached) {
+		list_for_each_entry(a, &buffer->attachments, list) {
+			if (!a->mapped)
+				continue;
+			dma_sync_sgtable_for_cpu(a->dev, a->table, direction);
+		}
 	}
+	mutex_unlock(&buffer->lock);
+
+	return 0;
+}
+
+static int system_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
+					      enum dma_data_direction direction)
+{
+	struct system_heap_buffer *buffer = dmabuf->priv;
+	struct dma_heap_attachment *a;
+
+	mutex_lock(&buffer->lock);
+
+	if (buffer->vmap_cnt)
+		flush_kernel_vmap_range(buffer->vaddr, buffer->len);
+
+	if (!buffer->uncached) {
+		list_for_each_entry(a, &buffer->attachments, list) {
+			if (!a->mapped)
+				continue;
+			dma_sync_sgtable_for_device(a->dev, a->table, direction);
+		}
+	}
+	mutex_unlock(&buffer->lock);
+
+	return 0;
+}
+
+static int system_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
+{
+	struct system_heap_buffer *buffer = dmabuf->priv;
+	struct sg_table *table = &buffer->sg_table;
+	unsigned long addr = vma->vm_start;
+	struct sg_page_iter piter;
+	int ret;
+
+	if (buffer->uncached)
+		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+
+	for_each_sgtable_page(table, &piter, vma->vm_pgoff) {
+		struct page *page = sg_page_iter_page(&piter);
+
+		ret = remap_pfn_range(vma, addr, page_to_pfn(page), PAGE_SIZE,
+				      vma->vm_page_prot);
+		if (ret)
+			return ret;
+		addr += PAGE_SIZE;
+		if (addr >= vma->vm_end)
+			return 0;
+	}
+	return 0;
+}
+
+static void *system_heap_do_vmap(struct system_heap_buffer *buffer)
+{
+	struct sg_table *table = &buffer->sg_table;
+	int npages = PAGE_ALIGN(buffer->len) / PAGE_SIZE;
+	struct page **pages = vmalloc(sizeof(struct page *) * npages);
+	struct page **tmp = pages;
+	struct sg_page_iter piter;
+	pgprot_t pgprot = PAGE_KERNEL;
+	void *vaddr;
+
+	if (!pages)
+		return ERR_PTR(-ENOMEM);
+
+	if (buffer->uncached)
+		pgprot = pgprot_writecombine(PAGE_KERNEL);
+
+	for_each_sgtable_page(table, &piter, 0) {
+		WARN_ON(tmp - pages >= npages);
+		*tmp++ = sg_page_iter_page(&piter);
+	}
+
+	vaddr = vmap(pages, npages, VM_MAP, pgprot);
+	vfree(pages);
+
+	if (!vaddr)
+		return ERR_PTR(-ENOMEM);
+
+	return vaddr;
+}
+
+static void *system_heap_vmap(struct dma_buf *dmabuf)
+{
+	struct system_heap_buffer *buffer = dmabuf->priv;
+	void *vaddr;
+
+	mutex_lock(&buffer->lock);
+	if (buffer->vmap_cnt) {
+		buffer->vmap_cnt++;
+		vaddr = buffer->vaddr;
+		goto out;
+	}
+
+	vaddr = system_heap_do_vmap(buffer);
+	if (IS_ERR(vaddr))
+		goto out;
+
+	buffer->vaddr = vaddr;
+	buffer->vmap_cnt++;
+out:
+	mutex_unlock(&buffer->lock);
 
-	for (pg = 0; pg < helper_buffer->pagecount; pg++) {
+	return vaddr;
+}
+
+static void system_heap_vunmap(struct dma_buf *dmabuf, void *vaddr)
+{
+	struct system_heap_buffer *buffer = dmabuf->priv;
+
+	mutex_lock(&buffer->lock);
+	if (!--buffer->vmap_cnt) {
+		vunmap(buffer->vaddr);
+		buffer->vaddr = NULL;
+	}
+	mutex_unlock(&buffer->lock);
+}
+
+static int system_heap_zero_buffer(struct system_heap_buffer *buffer)
+{
+	struct sg_table *sgt = &buffer->sg_table;
+	struct sg_page_iter piter;
+	struct page *p;
+	void *vaddr;
+	int ret = 0;
+
+	for_each_sgtable_page(sgt, &piter, 0) {
+		p = sg_page_iter_page(&piter);
+		vaddr = kmap_atomic(p);
+		memset(vaddr, 0, PAGE_SIZE);
+		kunmap_atomic(vaddr);
+	}
+
+	return ret;
+}
+
+static void system_heap_buf_free(struct deferred_freelist_item *item,
+				 enum df_reason reason)
+{
+	struct system_heap_buffer *buffer;
+	struct sg_table *table;
+	struct scatterlist *sg;
+	int i, j;
+
+	buffer = container_of(item, struct system_heap_buffer, deferred_free);
+	/* Zero the buffer pages before adding back to the pool */
+	if (reason == DF_NORMAL)
+		if (system_heap_zero_buffer(buffer))
+			reason = DF_UNDER_PRESSURE; // On failure, just free
+
+	table = &buffer->sg_table;
+	for_each_sgtable_sg(table, sg, i) {
+		struct page *page = sg_page(sg);
+
+		if (reason == DF_UNDER_PRESSURE) {
+			__free_pages(page, compound_order(page));
+		} else {
+			for (j = 0; j < NUM_ORDERS; j++) {
+				if (compound_order(page) == orders[j])
+					break;
+			}
+			dmabuf_page_pool_free(pools[j], page);
+		}
+	}
+	sg_free_table(table);
+	kfree(buffer);
+}
+
+static void system_heap_dma_buf_release(struct dma_buf *dmabuf)
+{
+	struct system_heap_buffer *buffer = dmabuf->priv;
+	int npages = PAGE_ALIGN(buffer->len) / PAGE_SIZE;
+
+	deferred_free(&buffer->deferred_free, system_heap_buf_free, npages);
+}
+
+static const struct dma_buf_ops system_heap_buf_ops = {
+	.attach = system_heap_attach,
+	.detach = system_heap_detach,
+	.map_dma_buf = system_heap_map_dma_buf,
+	.unmap_dma_buf = system_heap_unmap_dma_buf,
+	.begin_cpu_access = system_heap_dma_buf_begin_cpu_access,
+	.end_cpu_access = system_heap_dma_buf_end_cpu_access,
+	.mmap = system_heap_mmap,
+	.vmap = system_heap_vmap,
+	.vunmap = system_heap_vunmap,
+	.release = system_heap_dma_buf_release,
+};
+
+static struct page *alloc_largest_available(unsigned long size,
+					    unsigned int max_order)
+{
+	struct page *page;
+	int i;
+
+	for (i = 0; i < NUM_ORDERS; i++) {
+		if (size <  (PAGE_SIZE << orders[i]))
+			continue;
+		if (max_order < orders[i])
+			continue;
+		page = dmabuf_page_pool_alloc(pools[i]);
+		if (!page)
+			continue;
+		return page;
+	}
+	return NULL;
+}
+
+static struct dma_buf *system_heap_do_allocate(struct dma_heap *heap,
+					       unsigned long len,
+					       unsigned long fd_flags,
+					       unsigned long heap_flags,
+					       bool uncached)
+{
+	struct system_heap_buffer *buffer;
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+	unsigned long size_remaining = len;
+	unsigned int max_order = orders[0];
+	struct dma_buf *dmabuf;
+	struct sg_table *table;
+	struct scatterlist *sg;
+	struct list_head pages;
+	struct page *page, *tmp_page;
+	int i, ret = -ENOMEM;
+
+	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+	if (!buffer)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&buffer->attachments);
+	mutex_init(&buffer->lock);
+	buffer->heap = heap;
+	buffer->len = len;
+	buffer->uncached = uncached;
+
+	INIT_LIST_HEAD(&pages);
+	i = 0;
+	while (size_remaining > 0) {
 		/*
 		 * Avoid trying to allocate memory if the process
-		 * has been killed by by SIGKILL
+		 * has been killed by SIGKILL
 		 */
 		if (fatal_signal_pending(current))
-			goto err1;
+			goto free_buffer;
+
+		page = alloc_largest_available(size_remaining, max_order);
+		if (!page)
+			goto free_buffer;
+
+		list_add_tail(&page->lru, &pages);
+		size_remaining -= page_size(page);
+		max_order = compound_order(page);
+		i++;
+	}
 
-		helper_buffer->pages[pg] = alloc_page(GFP_KERNEL | __GFP_ZERO);
-		if (!helper_buffer->pages[pg])
-			goto err1;
+	table = &buffer->sg_table;
+	if (sg_alloc_table(table, i, GFP_KERNEL))
+		goto free_buffer;
+
+	sg = table->sgl;
+	list_for_each_entry_safe(page, tmp_page, &pages, lru) {
+		sg_set_page(sg, page, page_size(page), 0);
+		sg = sg_next(sg);
+		list_del(&page->lru);
 	}
 
 	/* create the dmabuf */
-	dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
+	exp_info.exp_name = dma_heap_get_name(heap);
+	exp_info.ops = &system_heap_buf_ops;
+	exp_info.size = buffer->len;
+	exp_info.flags = fd_flags;
+	exp_info.priv = buffer;
+	dmabuf = dma_buf_export(&exp_info);
 	if (IS_ERR(dmabuf)) {
 		ret = PTR_ERR(dmabuf);
-		goto err1;
+		goto free_pages;
+	}
+
+	/*
+	 * For uncached buffers, we need to initially flush cpu cache, since
+	 * the __GFP_ZERO on the allocation means the zeroing was done by the
+	 * cpu and thus it is likely cached. Map (and implicitly flush) and
+	 * unmap it now so we don't get corruption later on.
+	 */
+	if (buffer->uncached) {
+		dma_map_sgtable(dma_heap_get_dev(heap), table, DMA_BIDIRECTIONAL, 0);
+		dma_unmap_sgtable(dma_heap_get_dev(heap), table, DMA_BIDIRECTIONAL, 0);
 	}
 
-	helper_buffer->dmabuf = dmabuf;
+	return dmabuf;
 
-	ret = dma_buf_fd(dmabuf, fd_flags);
-	if (ret < 0) {
-		dma_buf_put(dmabuf);
-		/* just return, as put will call release and that will free */
-		return ret;
+free_pages:
+	for_each_sgtable_sg(table, sg, i) {
+		struct page *p = sg_page(sg);
+
+		__free_pages(p, compound_order(p));
 	}
+	sg_free_table(table);
+free_buffer:
+	list_for_each_entry_safe(page, tmp_page, &pages, lru)
+		__free_pages(page, compound_order(page));
+	kfree(buffer);
 
-	return ret;
+	return ERR_PTR(ret);
+}
 
-err1:
-	while (pg > 0)
-		__free_page(helper_buffer->pages[--pg]);
-	kfree(helper_buffer->pages);
-err0:
-	kfree(helper_buffer);
+static struct dma_buf *system_heap_allocate(struct dma_heap *heap,
+					    unsigned long len,
+					    unsigned long fd_flags,
+					    unsigned long heap_flags)
+{
+	return system_heap_do_allocate(heap, len, fd_flags, heap_flags, false);
+}
 
-	return ret;
+static long system_get_pool_size(struct dma_heap *heap)
+{
+	int i;
+	long num_pages = 0;
+	struct dmabuf_page_pool **pool;
+
+	pool = pools;
+	for (i = 0; i < NUM_ORDERS; i++, pool++) {
+		num_pages += ((*pool)->count[POOL_LOWPAGE] +
+			      (*pool)->count[POOL_HIGHPAGE]) << (*pool)->order;
+	}
+
+	return num_pages << PAGE_SHIFT;
 }
 
 static const struct dma_heap_ops system_heap_ops = {
 	.allocate = system_heap_allocate,
+	.get_pool_size = system_get_pool_size,
+};
+
+static struct dma_buf *system_uncached_heap_allocate(struct dma_heap *heap,
+						     unsigned long len,
+						     unsigned long fd_flags,
+						     unsigned long heap_flags)
+{
+	return system_heap_do_allocate(heap, len, fd_flags, heap_flags, true);
+}
+
+/* Dummy function to be used until we can call coerce_mask_and_coherent */
+static struct dma_buf *system_uncached_heap_not_initialized(struct dma_heap *heap,
+							    unsigned long len,
+							    unsigned long fd_flags,
+							    unsigned long heap_flags)
+{
+	return ERR_PTR(-EBUSY);
+}
+
+static struct dma_heap_ops system_uncached_heap_ops = {
+	/* After system_heap_create is complete, we will swap this */
+	.allocate = system_uncached_heap_not_initialized,
 };
 
 static int system_heap_create(void)
 {
 	struct dma_heap_export_info exp_info;
-	int ret = 0;
+	int i;
+
+	for (i = 0; i < NUM_ORDERS; i++) {
+		pools[i] = dmabuf_page_pool_create(order_flags[i], orders[i]);
+
+		if (!pools[i]) {
+			int j;
+
+			pr_err("%s: page pool creation failed!\n", __func__);
+			for (j = 0; j < i; j++)
+				dmabuf_page_pool_destroy(pools[j]);
+			return -ENOMEM;
+		}
+	}
 
 	exp_info.name = "system";
 	exp_info.ops = &system_heap_ops;
@@ -115,9 +567,21 @@ static int system_heap_create(void)
 
 	sys_heap = dma_heap_add(&exp_info);
 	if (IS_ERR(sys_heap))
-		ret = PTR_ERR(sys_heap);
+		return PTR_ERR(sys_heap);
 
-	return ret;
+	exp_info.name = "system-uncached";
+	exp_info.ops = &system_uncached_heap_ops;
+	exp_info.priv = NULL;
+
+	sys_uncached_heap = dma_heap_add(&exp_info);
+	if (IS_ERR(sys_uncached_heap))
+		return PTR_ERR(sys_uncached_heap);
+
+	dma_coerce_mask_and_coherent(dma_heap_get_dev(sys_uncached_heap), DMA_BIT_MASK(64));
+	mb(); /* make sure we only set allocate after dma_mask is set */
+	system_uncached_heap_ops.allocate = system_uncached_heap_allocate;
+
+	return 0;
 }
 module_init(system_heap_create);
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
index 109d11fb4..4aac2ec86 100644
--- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
+++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
@@ -461,9 +461,10 @@ int drm_gem_fb_prepare_fb(struct drm_plane *plane,
 		return 0;
 
 	obj = drm_gem_fb_get_obj(state->fb, 0);
-	fence = dma_resv_get_excl_rcu(obj->resv);
-	drm_atomic_set_fence_for_plane(state, fence);
-
+	if (obj) {
+		fence = dma_resv_get_excl_rcu(obj->resv);
+		drm_atomic_set_fence_for_plane(state, fence);
+	}
 	return 0;
 }
 EXPORT_SYMBOL_GPL(drm_gem_fb_prepare_fb);
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index f135b7959..fc9c53e3e 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -1100,7 +1100,7 @@ static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
 		return dev->driver->enable_vblank(dev, pipe);
 	}
 
-	return -EINVAL;
+	return 0;
 }
 
 static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 0c5706abb..528cd83d3 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -289,14 +289,9 @@ struct dma_buf_ops {
  * @list_node: node for dma_buf accounting and debugging.
  * @priv: exporter specific private data for this buffer object.
  * @resv: reservation object linked to this dma-buf
- * @exp_pid: pid of exporter task which created this obj
- * @exp_task_comm: process name of exporter task which created this obj
  * @poll: for userspace poll support
  * @cb_excl: for userspace poll support
  * @cb_shared: for userspace poll support
- * @sysfs_entry: for exposing information about this buffer in sysfs.
- * The attachment_uid member of @sysfs_entry is protected by dma_resv lock
- * and is incremented on each attach.
  *
  * This represents a shared buffer, created by calling dma_buf_export(). The
  * userspace representation is a normal file descriptor, which can be created by
@@ -322,10 +317,6 @@ struct dma_buf {
 	struct list_head list_node;
 	void *priv;
 	struct dma_resv *resv;
-#ifdef CONFIG_DMABUF_PROCESS_INFO
-	pid_t exp_pid;
-	char exp_task_comm[TASK_COMM_LEN];
-#endif
 
 	/* poll support */
 	wait_queue_head_t poll;
@@ -336,13 +327,6 @@ struct dma_buf {
 
 		__poll_t active;
 	} cb_excl, cb_shared;
-#ifdef CONFIG_DMABUF_SYSFS_STATS
-	/* for sysfs stats */
-	struct dma_buf_sysfs_entry {
-		struct kobject kobj;
-		struct dma_buf *dmabuf;
-	} *sysfs_entry;
-#endif
 };
 
 /**
@@ -412,6 +396,7 @@ struct dma_buf_attachment {
 	const struct dma_buf_attach_ops *importer_ops;
 	void *importer_priv;
 	void *priv;
+	unsigned long dma_map_attrs;
 };
 
 /**
@@ -520,16 +505,4 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
 		 unsigned long);
 void *dma_buf_vmap(struct dma_buf *);
 void dma_buf_vunmap(struct dma_buf *, void *vaddr);
-
-#ifdef CONFIG_DMABUF_PROCESS_INFO
-/**
- * get_dma_buf_from_file - Get struct dma_buf* from struct file*
- * @f:	[in]	pointer to struct file, which is associated with a
- *		dma_buf object.
- *
- * If @f IS_ERR_OR_NULL, return NULL.
- * If @f is not a file associated with dma_buf, return NULL.
- */
-struct dma_buf *get_dma_buf_from_file(struct file *f);
-#endif /* CONFIG_DMABUF_PROCESS_INFO */
 #endif /* __DMA_BUF_H__ */
diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
index 83b8cfb2d..e8f0e92c2 100644
--- a/include/linux/dma-heap.h
+++ b/include/linux/dma-heap.h
@@ -16,15 +16,17 @@ struct dma_heap;
 
 /**
  * struct dma_heap_ops - ops to operate on a given heap
- * @allocate:		allocate dmabuf and return fd
+ * @allocate:		allocate dmabuf and return struct dma_buf ptr
+ * @get_pool_size:	if heap maintains memory pools, get pool size in bytes
  *
- * allocate returns dmabuf fd  on success, -errno on error.
+ * allocate returns dmabuf on success, ERR_PTR(-errno) on error.
  */
 struct dma_heap_ops {
-	int (*allocate)(struct dma_heap *heap,
+	struct dma_buf *(*allocate)(struct dma_heap *heap,
 			unsigned long len,
 			unsigned long fd_flags,
 			unsigned long heap_flags);
+	long (*get_pool_size)(struct dma_heap *heap);
 };
 
 /**
@@ -50,6 +52,15 @@ struct dma_heap_export_info {
  */
 void *dma_heap_get_drvdata(struct dma_heap *heap);
 
+/**
+ * dma_heap_get_dev() - get device struct for the heap
+ * @heap: DMA-Heap to retrieve device struct from
+ *
+ * Returns:
+ * The device struct for the heap.
+ */
+struct device *dma_heap_get_dev(struct dma_heap *heap);
+
 /**
  * dma_heap_get_name() - get heap name
  * @heap: DMA-Heap to retrieve private data for
@@ -65,4 +76,49 @@ const char *dma_heap_get_name(struct dma_heap *heap);
  */
 struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);
 
+/**
+ * dma_heap_put - drops a reference to a dmabuf heaps, potentially freeing it
+ * @heap:		heap pointer
+ */
+void dma_heap_put(struct dma_heap *heap);
+
+/**
+ * dma_heap_find - Returns the registered dma_heap with the specified name
+ * @name: Name of the heap to find
+ *
+ * NOTE: dma_heaps returned from this function MUST be released
+ * using dma_heap_put() when the user is done.
+ */
+struct dma_heap *dma_heap_find(const char *name);
+
+/**
+ * dma_heap_buffer_alloc - Allocate dma-buf from a dma_heap
+ * @heap:	dma_heap to allocate from
+ * @len:	size to allocate
+ * @fd_flags:	flags to set on returned dma-buf fd
+ * @heap_flags:	flags to pass to the dma heap
+ *
+ * This is for internal dma-buf allocations only.
+ */
+struct dma_buf *dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
+				      unsigned int fd_flags,
+				      unsigned int heap_flags);
+
+/** dma_heap_buffer_free - Free dma_buf allocated by dma_heap_buffer_alloc
+ * @dma_buf:	dma_buf to free
+ *
+ * This is really only a simple wrapper to dma_buf_put()
+ */
+void dma_heap_buffer_free(struct dma_buf *);
+
+/**
+ * dma_heap_bufferfd_alloc - Allocate dma-buf fd from a dma_heap
+ * @heap:	dma_heap to allocate from
+ * @len:	size to allocate
+ * @fd_flags:	flags to set on returned dma-buf fd
+ * @heap_flags:	flags to pass to the dma heap
+ */
+int dma_heap_bufferfd_alloc(struct dma_heap *heap, size_t len,
+			    unsigned int fd_flags,
+			    unsigned int heap_flags);
 #endif /* _DMA_HEAPS_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 46a0df7d1..2909709f4 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5636,16 +5636,19 @@ int sched_setscheduler(struct task_struct *p, int policy,
 {
 	return _sched_setscheduler(p, policy, param, true);
 }
+EXPORT_SYMBOL_GPL(sched_setscheduler);
 
 int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
 {
 	return __sched_setscheduler(p, attr, true, true);
 }
+EXPORT_SYMBOL_GPL(sched_setattr);
 
 int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
 {
 	return __sched_setscheduler(p, attr, false, true);
 }
+EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck);
 
 /**
  * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
-- 
2.25.1