Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/mm/zswap.c b/mm/zswap.c
index cd91fd9..46a3223 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * zswap.c - zswap driver file
  *
@@ -8,16 +9,6 @@
  * than reading from the swap device, can also improve workload performance.
  *
  * Copyright (C) 2012  Seth Jennings <sjenning@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
 */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -219,8 +210,8 @@
 
 static bool zswap_is_full(void)
 {
-	return totalram_pages * zswap_max_pool_percent / 100 <
-		DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
+	return totalram_pages() * zswap_max_pool_percent / 100 <
+			DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
 }
 
 static void zswap_update_total_size(void)
@@ -865,7 +856,6 @@
 	/* extract swpentry from data */
 	zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO);
 	swpentry = zhdr->swpentry; /* here */
-	zpool_unmap_handle(pool, handle);
 	tree = zswap_trees[swp_type(swpentry)];
 	offset = swp_offset(swpentry);
 
@@ -875,6 +865,7 @@
 	if (!entry) {
 		/* entry was invalidated */
 		spin_unlock(&tree->lock);
+		zpool_unmap_handle(pool, handle);
 		return 0;
 	}
 	spin_unlock(&tree->lock);
@@ -895,15 +886,13 @@
 	case ZSWAP_SWAPCACHE_NEW: /* page is locked */
 		/* decompress */
 		dlen = PAGE_SIZE;
-		src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
-				ZPOOL_MM_RO) + sizeof(struct zswap_header);
+		src = (u8 *)zhdr + sizeof(struct zswap_header);
 		dst = kmap_atomic(page);
 		tfm = *get_cpu_ptr(entry->pool->tfm);
 		ret = crypto_comp_decompress(tfm, src, entry->length,
 					     dst, &dlen);
 		put_cpu_ptr(entry->pool->tfm);
 		kunmap_atomic(dst);
-		zpool_unmap_handle(entry->pool->zpool, entry->handle);
 		BUG_ON(ret);
 		BUG_ON(dlen != PAGE_SIZE);
 
@@ -949,6 +938,7 @@
 	spin_unlock(&tree->lock);
 
 end:
+	zpool_unmap_handle(pool, handle);
 	return ret;
 }
 
@@ -1006,6 +996,7 @@
 	char *buf;
 	u8 *src, *dst;
 	struct zswap_header zhdr = { .swpentry = swp_entry(type, offset) };
+	gfp_t gfp;
 
 	/* THP isn't supported */
 	if (PageTransHuge(page)) {
@@ -1079,9 +1070,10 @@
 
 	/* store */
 	hlen = zpool_evictable(entry->pool->zpool) ? sizeof(zhdr) : 0;
-	ret = zpool_malloc(entry->pool->zpool, hlen + dlen,
-			   __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM,
-			   &handle);
+	gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
+	if (zpool_malloc_support_movable(entry->pool->zpool))
+		gfp |= __GFP_HIGHMEM | __GFP_MOVABLE;
+	ret = zpool_malloc(entry->pool->zpool, hlen + dlen, gfp, &handle);
 	if (ret == -ENOSPC) {
 		zswap_reject_compress_poor++;
 		goto put_dstmem;
@@ -1262,8 +1254,6 @@
 		return -ENODEV;
 
 	zswap_debugfs_root = debugfs_create_dir("zswap", NULL);
-	if (!zswap_debugfs_root)
-		return -ENOMEM;
 
 	debugfs_create_u64("pool_limit_hit", 0444,
 			   zswap_debugfs_root, &zswap_pool_limit_hit);