1 files changed, 36 insertions, 22 deletions

diff --git a/kernel/memremap.c b/kernel/memremap.c
index e517a16cb426..fb9b88787ebc 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -29,10 +29,10 @@ __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
 
 static void *try_ram_remap(resource_size_t offset, size_t size)
 {
-	struct page *page = pfn_to_page(offset >> PAGE_SHIFT);
+	unsigned long pfn = PHYS_PFN(offset);
 
 	/* In the simple case just return the existing linear address */
-	if (!PageHighMem(page))
+	if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)))
 		return __va(offset);
 	return NULL; /* fallback to ioremap_cache */
 }
@@ -47,7 +47,7 @@ static void *try_ram_remap(resource_size_t offset, size_t size)
  * being mapped does not have i/o side effects and the __iomem
  * annotation is not applicable.
  *
- * MEMREMAP_WB - matches the default mapping for "System RAM" on
+ * MEMREMAP_WB - matches the default mapping for System RAM on
  * the architecture.  This is usually a read-allocate write-back cache.
  * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
  * memremap() will bypass establishing a new mapping and instead return
@@ -56,11 +56,12 @@ static void *try_ram_remap(resource_size_t offset, size_t size)
  * MEMREMAP_WT - establish a mapping whereby writes either bypass the
  * cache or are written through to memory and never exist in a
  * cache-dirty state with respect to program visibility.  Attempts to
- * map "System RAM" with this mapping type will fail.
+ * map System RAM with this mapping type will fail.
  */
 void *memremap(resource_size_t offset, size_t size, unsigned long flags)
 {
-	int is_ram = region_intersects(offset, size, "System RAM");
+	int is_ram = region_intersects(offset, size,
+				       IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
 	void *addr = NULL;
 
 	if (is_ram == REGION_MIXED) {
@@ -76,7 +77,7 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
 		 * MEMREMAP_WB is special in that it can be satisifed
 		 * from the direct map.  Some archs depend on the
 		 * capability of memremap() to autodetect cases where
-		 * the requested range is potentially in "System RAM"
+		 * the requested range is potentially in System RAM.
 		 */
 		if (is_ram == REGION_INTERSECTS)
 			addr = try_ram_remap(offset, size);
@@ -88,7 +89,7 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
 	 * If we don't have a mapping yet and more request flags are
 	 * pending then we will be attempting to establish a new virtual
 	 * address mapping.  Enforce that this mapping is not aliasing
-	 * "System RAM"
+	 * System RAM.
 	 */
 	if (!addr && is_ram == REGION_INTERSECTS && flags) {
 		WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
@@ -114,7 +115,7 @@ EXPORT_SYMBOL(memunmap);
 
 static void devm_memremap_release(struct device *dev, void *res)
 {
-	memunmap(res);
+	memunmap(*(void **)res);
 }
 
 static int devm_memremap_match(struct device *dev, void *res, void *match_data)
@@ -136,8 +137,10 @@ void *devm_memremap(struct device *dev, resource_size_t offset,
 	if (addr) {
 		*ptr = addr;
 		devres_add(dev, ptr);
-	} else
+	} else {
 		devres_free(ptr);
+		return ERR_PTR(-ENXIO);
+	}
 
 	return addr;
 }
@@ -150,7 +153,7 @@ void devm_memunmap(struct device *dev, void *addr)
 }
 EXPORT_SYMBOL(devm_memunmap);
 
-pfn_t phys_to_pfn_t(dma_addr_t addr, unsigned long flags)
+pfn_t phys_to_pfn_t(phys_addr_t addr, u64 flags)
 {
 	return __pfn_to_pfn_t(addr >> PAGE_SHIFT, flags);
 }
@@ -183,7 +186,11 @@ EXPORT_SYMBOL(put_zone_device_page);
 
 static void pgmap_radix_release(struct resource *res)
 {
-	resource_size_t key;
+	resource_size_t key, align_start, align_size, align_end;
+
+	align_start = res->start & ~(SECTION_SIZE - 1);
+	align_size = ALIGN(resource_size(res), SECTION_SIZE);
+	align_end = align_start + align_size - 1;
 
 	mutex_lock(&pgmap_lock);
 	for (key = res->start; key <= res->end; key += SECTION_SIZE)
@@ -226,12 +233,11 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
 		percpu_ref_put(pgmap->ref);
 	}
 
-	pgmap_radix_release(res);
-
 	/* pages are dead and unused, undo the arch mapping */
 	align_start = res->start & ~(SECTION_SIZE - 1);
 	align_size = ALIGN(resource_size(res), SECTION_SIZE);
 	arch_remove_memory(align_start, align_size);
+	pgmap_radix_release(res);
 	dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
 			"%s: failed to free all reserved pages\n", __func__);
 }
@@ -265,13 +271,17 @@ struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
 void *devm_memremap_pages(struct device *dev, struct resource *res,
 		struct percpu_ref *ref, struct vmem_altmap *altmap)
 {
-	int is_ram = region_intersects(res->start, resource_size(res),
-			"System RAM");
-	resource_size_t key, align_start, align_size;
+	resource_size_t key, align_start, align_size, align_end;
 	struct dev_pagemap *pgmap;
 	struct page_map *page_map;
+	int error, nid, is_ram;
 	unsigned long pfn;
-	int error, nid;
+
+	align_start = res->start & ~(SECTION_SIZE - 1);
+	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
+		- align_start;
+	is_ram = region_intersects(align_start, align_size,
+		IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
 
 	if (is_ram == REGION_MIXED) {
 		WARN_ONCE(1, "%s attempted on mixed region %pr\n",
@@ -309,7 +319,8 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
 
 	mutex_lock(&pgmap_lock);
 	error = 0;
-	for (key = res->start; key <= res->end; key += SECTION_SIZE) {
+	align_end = align_start + align_size - 1;
+	for (key = align_start; key <= align_end; key += SECTION_SIZE) {
 		struct dev_pagemap *dup;
 
 		rcu_read_lock();
@@ -336,8 +347,6 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
 	if (nid < 0)
 		nid = numa_mem_id();
 
-	align_start = res->start & ~(SECTION_SIZE - 1);
-	align_size = ALIGN(resource_size(res), SECTION_SIZE);
 	error = arch_add_memory(nid, align_start, align_size, true);
 	if (error)
 		goto err_add_memory;
@@ -345,8 +354,13 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
 	for_each_device_pfn(pfn, page_map) {
 		struct page *page = pfn_to_page(pfn);
 
-		/* ZONE_DEVICE pages must never appear on a slab lru */
-		list_force_poison(&page->lru);
+		/*
+		 * ZONE_DEVICE pages union ->lru with a ->pgmap back
+		 * pointer.  It is a bug if a ZONE_DEVICE page is ever
+		 * freed or placed on a driver-private list.  Seed the
+		 * storage with LIST_POISON* values.
+		 */
+		list_del(&page->lru);
 		page->pgmap = pgmap;
 	}
 	devres_add(dev, page_map);