Inline vfs.VirtualFilesystem in Kernel struct

This saves one pointer dereference per VFS access.

Updates #1623

PiperOrigin-RevId: 295216176

3 files changed, 17 insertions, 4 deletions

diff --git a/pkg/sentry/fsimpl/tmpfs/benchmark_test.go b/pkg/sentry/fsimpl/tmpfs/benchmark_test.go
index 9fce5e4b4..383133e44 100644
--- a/pkg/sentry/fsimpl/tmpfs/benchmark_test.go
+++ b/pkg/sentry/fsimpl/tmpfs/benchmark_test.go
@@ -175,7 +175,10 @@ func BenchmarkVFS2MemfsStat(b *testing.B) {
 			creds := auth.CredentialsFromContext(ctx)
 
 			// Create VFS.
-			vfsObj := vfs.New()
+			vfsObj := vfs.VirtualFilesystem{}
+			if err := vfsObj.Init(); err != nil {
+				b.Fatalf("VFS init: %v", err)
+			}
 			vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 				AllowUserMount: true,
 			})
@@ -366,7 +369,10 @@ func BenchmarkVFS2MemfsMountStat(b *testing.B) {
 			creds := auth.CredentialsFromContext(ctx)
 
 			// Create VFS.
-			vfsObj := vfs.New()
+			vfsObj := vfs.VirtualFilesystem{}
+			if err := vfsObj.Init(); err != nil {
+				b.Fatalf("VFS init: %v", err)
+			}
 			vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 				AllowUserMount: true,
 			})
diff --git a/pkg/sentry/fsimpl/tmpfs/pipe_test.go b/pkg/sentry/fsimpl/tmpfs/pipe_test.go
index 5ee7f2a72..1614f2c39 100644
--- a/pkg/sentry/fsimpl/tmpfs/pipe_test.go
+++ b/pkg/sentry/fsimpl/tmpfs/pipe_test.go
@@ -151,7 +151,10 @@ func setup(t *testing.T) (context.Context, *auth.Credentials, *vfs.VirtualFilesy
 	creds := auth.CredentialsFromContext(ctx)
 
 	// Create VFS.
-	vfsObj := vfs.New()
+	vfsObj := &vfs.VirtualFilesystem{}
+	if err := vfsObj.Init(); err != nil {
+		t.Fatalf("VFS init: %v", err)
+	}
 	vfsObj.MustRegisterFilesystemType("tmpfs", FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})
diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file_test.go b/pkg/sentry/fsimpl/tmpfs/regular_file_test.go
index e9f71e334..0399725cf 100644
--- a/pkg/sentry/fsimpl/tmpfs/regular_file_test.go
+++ b/pkg/sentry/fsimpl/tmpfs/regular_file_test.go
@@ -40,7 +40,11 @@ var nextFileID int64
 func newTmpfsRoot(ctx context.Context) (*vfs.VirtualFilesystem, vfs.VirtualDentry, func(), error) {
 	creds := auth.CredentialsFromContext(ctx)
 
-	vfsObj := vfs.New()
+	vfsObj := &vfs.VirtualFilesystem{}
+	if err := vfsObj.Init(); err != nil {
+		return nil, vfs.VirtualDentry{}, nil, fmt.Errorf("VFS init: %v", err)
+	}
+
 	vfsObj.MustRegisterFilesystemType("tmpfs", FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
 		AllowUserMount: true,
 	})