Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 8fafbea..eccdda1 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -227,7 +227,7 @@
 
 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
 		struct resource *res, int target_node, unsigned int align,
-		unsigned long pfn_flags)
+		unsigned long long pfn_flags)
 {
 	struct dax_region *dax_region;
 
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index 8619e32..9e4eba6 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -11,7 +11,7 @@
 void dax_region_put(struct dax_region *dax_region);
 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
 		struct resource *res, int target_node, unsigned int align,
-		unsigned long flags);
+		unsigned long long flags);
 
 enum dev_dax_subsys {
 	DEV_DAX_BUS,
diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index 6ccca3b..3107ce8 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -32,7 +32,7 @@
 	struct device *dev;
 	unsigned int align;
 	struct resource res;
-	unsigned long pfn_flags;
+	unsigned long long pfn_flags;
 };
 
 /**
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 3d0a7e7..1e678bd 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -22,6 +22,7 @@
 	resource_size_t kmem_size;
 	resource_size_t kmem_end;
 	struct resource *new_res;
+	const char *new_res_name;
 	int numa_node;
 	int rc;
 
@@ -48,11 +49,16 @@
 	kmem_size &= ~(memory_block_size_bytes() - 1);
 	kmem_end = kmem_start + kmem_size;
 
-	/* Region is permanently reserved.  Hot-remove not yet implemented. */
-	new_res = request_mem_region(kmem_start, kmem_size, dev_name(dev));
+	new_res_name = kstrdup(dev_name(dev), GFP_KERNEL);
+	if (!new_res_name)
+		return -ENOMEM;
+
+	/* Region is permanently reserved if hotremove fails. */
+	new_res = request_mem_region(kmem_start, kmem_size, new_res_name);
 	if (!new_res) {
 		dev_warn(dev, "could not reserve region [%pa-%pa]\n",
 			 &kmem_start, &kmem_end);
+		kfree(new_res_name);
 		return -EBUSY;
 	}
 
@@ -63,12 +69,12 @@
 	 * unknown to us that will break add_memory() below.
 	 */
 	new_res->flags = IORESOURCE_SYSTEM_RAM;
-	new_res->name = dev_name(dev);
 
 	rc = add_memory(numa_node, new_res->start, resource_size(new_res));
 	if (rc) {
 		release_resource(new_res);
 		kfree(new_res);
+		kfree(new_res_name);
 		return rc;
 	}
 	dev_dax->dax_kmem_res = new_res;
@@ -83,6 +89,7 @@
 	struct resource *res = dev_dax->dax_kmem_res;
 	resource_size_t kmem_start = res->start;
 	resource_size_t kmem_size = resource_size(res);
+	const char *res_name = res->name;
 	int rc;
 
 	/*
@@ -102,6 +109,7 @@
 	/* Release and free dax resources */
 	release_resource(res);
 	kfree(res);
+	kfree(res_name);
 	dev_dax->dax_kmem_res = NULL;
 
 	return 0;
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 26a654d..8074e5d 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -318,11 +318,15 @@
 bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
 		int blocksize, sector_t start, sector_t len)
 {
+	if (!dax_dev)
+		return false;
+
 	if (!dax_alive(dax_dev))
 		return false;
 
 	return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
 }
+EXPORT_SYMBOL_GPL(dax_supported);
 
 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 		size_t bytes, struct iov_iter *i)
@@ -716,6 +720,7 @@
 
 static void __exit dax_core_exit(void)
 {
+	dax_bus_exit();
 	unregister_chrdev_region(dax_devt, MINORMASK+1);
 	ida_destroy(&dax_minor_ida);
 	dax_fs_exit();