diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e2afe52..7bda842 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -523,7 +523,7 @@
 };
 
 /* Once caching_thread() finds this much free space, it will wake up waiters. */
-#define CACHING_CTL_WAKE_UP (1024 * 1024 * 2)
+#define CACHING_CTL_WAKE_UP SZ_2M
 
 struct btrfs_io_ctl {
 	void *cur, *orig;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 69ce738..484cf8f 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2733,7 +2733,7 @@
 	sb->s_bdi->congested_fn = btrfs_congested_fn;
 	sb->s_bdi->congested_data = fs_info;
 	sb->s_bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
-	sb->s_bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
+	sb->s_bdi->ra_pages = VM_MAX_READAHEAD * SZ_1K / PAGE_SIZE;
 	sb->s_bdi->ra_pages *= btrfs_super_num_devices(disk_super);
 	sb->s_bdi->ra_pages = max(sb->s_bdi->ra_pages, SZ_4M / PAGE_SIZE);
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 880ab49..4fb7eef 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2126,7 +2126,7 @@
 	 * succeed even if the Avail is zero. But this is better than the other
 	 * way around.
 	 */
-	thresh = 4 * 1024 * 1024;
+	thresh = SZ_4M;
 
 	if (!mixed && total_free_meta - thresh < block_rsv->size)
 		buf->f_bavail = 0;
diff --git a/fs/btrfs/tests/inode-tests.c b/fs/btrfs/tests/inode-tests.c
index 8c91d03..330815e 100644
--- a/fs/btrfs/tests/inode-tests.c
+++ b/fs/btrfs/tests/inode-tests.c
@@ -770,7 +770,7 @@
 	offset = em->start + em->len;
 	free_extent_map(em);
 
-	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, offset, 4096 * 1024, 0);
+	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, offset, SZ_4M, 0);
 	if (IS_ERR(em)) {
 		test_msg("Got an error when we shouldn't have\n");
 		goto out;