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/mm/zsmalloc.c b/mm/zsmalloc.c
index 2b2b9aa..443b3b1 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -293,11 +293,7 @@
 };
 
 struct mapping_area {
-#ifdef CONFIG_PGTABLE_MAPPING
-	struct vm_struct *vm; /* vm area for mapping object that span pages */
-#else
 	char *vm_buf; /* copy buffer for objects that span pages */
-#endif
 	char *vm_addr; /* address of kmap_atomic()'ed pages */
 	enum zs_mapmode vm_mm; /* mapping mode */
 };
@@ -1113,46 +1109,6 @@
 	return zspage;
 }
 
-#ifdef CONFIG_PGTABLE_MAPPING
-static inline int __zs_cpu_up(struct mapping_area *area)
-{
-	/*
-	 * Make sure we don't leak memory if a cpu UP notification
-	 * and zs_init() race and both call zs_cpu_up() on the same cpu
-	 */
-	if (area->vm)
-		return 0;
-	area->vm = alloc_vm_area(PAGE_SIZE * 2, NULL);
-	if (!area->vm)
-		return -ENOMEM;
-	return 0;
-}
-
-static inline void __zs_cpu_down(struct mapping_area *area)
-{
-	if (area->vm)
-		free_vm_area(area->vm);
-	area->vm = NULL;
-}
-
-static inline void *__zs_map_object(struct mapping_area *area,
-				struct page *pages[2], int off, int size)
-{
-	BUG_ON(map_vm_area(area->vm, PAGE_KERNEL, pages));
-	area->vm_addr = area->vm->addr;
-	return area->vm_addr + off;
-}
-
-static inline void __zs_unmap_object(struct mapping_area *area,
-				struct page *pages[2], int off, int size)
-{
-	unsigned long addr = (unsigned long)area->vm_addr;
-
-	unmap_kernel_range(addr, PAGE_SIZE * 2);
-}
-
-#else /* CONFIG_PGTABLE_MAPPING */
-
 static inline int __zs_cpu_up(struct mapping_area *area)
 {
 	/*
@@ -1233,8 +1189,6 @@
 	pagefault_enable();
 }
 
-#endif /* CONFIG_PGTABLE_MAPPING */
-
 static int zs_cpu_prepare(unsigned int cpu)
 {
 	struct mapping_area *area;
@@ -2069,6 +2023,11 @@
 		zs_pool_dec_isolated(pool);
 	}
 
+	if (page_zone(newpage) != page_zone(page)) {
+		dec_zone_page_state(page, NR_ZSPAGES);
+		inc_zone_page_state(newpage, NR_ZSPAGES);
+	}
+
 	reset_page(page);
 	put_page(page);
 	page = newpage;
@@ -2257,11 +2216,13 @@
 	return obj_wasted * class->pages_per_zspage;
 }
 
-static void __zs_compact(struct zs_pool *pool, struct size_class *class)
+static unsigned long __zs_compact(struct zs_pool *pool,
+				  struct size_class *class)
 {
 	struct zs_compact_control cc;
 	struct zspage *src_zspage;
 	struct zspage *dst_zspage = NULL;
+	unsigned long pages_freed = 0;
 
 	spin_lock(&class->lock);
 	while ((src_zspage = isolate_zspage(class, true))) {
@@ -2291,7 +2252,7 @@
 		putback_zspage(class, dst_zspage);
 		if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
 			free_zspage(pool, class, src_zspage);
-			pool->stats.pages_compacted += class->pages_per_zspage;
+			pages_freed += class->pages_per_zspage;
 		}
 		spin_unlock(&class->lock);
 		cond_resched();
@@ -2302,12 +2263,15 @@
 		putback_zspage(class, src_zspage);
 
 	spin_unlock(&class->lock);
+
+	return pages_freed;
 }
 
 unsigned long zs_compact(struct zs_pool *pool)
 {
 	int i;
 	struct size_class *class;
+	unsigned long pages_freed = 0;
 
 	for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
 		class = pool->size_class[i];
@@ -2315,10 +2279,11 @@
 			continue;
 		if (class->index != i)
 			continue;
-		__zs_compact(pool, class);
+		pages_freed += __zs_compact(pool, class);
 	}
+	atomic_long_add(pages_freed, &pool->stats.pages_compacted);
 
-	return pool->stats.pages_compacted;
+	return pages_freed;
 }
 EXPORT_SYMBOL_GPL(zs_compact);
 
@@ -2335,13 +2300,12 @@
 	struct zs_pool *pool = container_of(shrinker, struct zs_pool,
 			shrinker);
 
-	pages_freed = pool->stats.pages_compacted;
 	/*
 	 * Compact classes and calculate compaction delta.
 	 * Can run concurrently with a manually triggered
 	 * (by user) compaction.
 	 */
-	pages_freed = zs_compact(pool) - pages_freed;
+	pages_freed = zs_compact(pool);
 
 	return pages_freed ? pages_freed : SHRINK_STOP;
 }