Use new reference count utility throughout gvisor.

This uses the refs_vfs2 template in vfs2 as well as objects common to vfs1 and
vfs2. Note that vfs1-only refcounts are not replaced, since vfs1 will be deleted
soon anyway.

The following structs now use the new tool, with leak check enabled:
devpts:rootInode
fuse:inode
kernfs:Dentry
kernfs:dir
kernfs:readonlyDir
kernfs:StaticDirectory
proc:fdDirInode
proc:fdInfoDirInode
proc:subtasksInode
proc:taskInode
proc:tasksInode
vfs:FileDescription
vfs:MountNamespace
vfs:Filesystem
sys:dir
kernel:FSContext
kernel:ProcessGroup
kernel:Session
shm:Shm
mm:aioMappable
mm:SpecialMappable
transport:queue

And the following use the template, but because they currently are not leak
checked, a TODO is left instead of enabling leak check in this patch:
kernel:FDTable
tun:tunEndpoint

Updates #1486.

PiperOrigin-RevId: 328460377

2 files changed, 18 insertions, 5 deletions

diff --git a/pkg/tcpip/link/tun/BUILD b/pkg/tcpip/link/tun/BUILD
index 6c137f693..0243424f6 100644
--- a/pkg/tcpip/link/tun/BUILD
+++ b/pkg/tcpip/link/tun/BUILD
@@ -1,18 +1,32 @@
 load("//tools:defs.bzl", "go_library")
+load("//tools/go_generics:defs.bzl", "go_template_instance")
 
 package(licenses = ["notice"])
 
+go_template_instance(
+    name = "tun_endpoint_refs",
+    out = "tun_endpoint_refs.go",
+    package = "tun",
+    prefix = "tunEndpoint",
+    template = "//pkg/refs_vfs2:refs_template",
+    types = {
+        "T": "tunEndpoint",
+    },
+)
+
 go_library(
     name = "tun",
     srcs = [
         "device.go",
         "protocol.go",
+        "tun_endpoint_refs.go",
         "tun_unsafe.go",
     ],
     visibility = ["//visibility:public"],
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/log",
         "//pkg/refs",
         "//pkg/sync",
         "//pkg/syserror",
diff --git a/pkg/tcpip/link/tun/device.go b/pkg/tcpip/link/tun/device.go
index 3b1510a33..b6ddbe81e 100644
--- a/pkg/tcpip/link/tun/device.go
+++ b/pkg/tcpip/link/tun/device.go
@@ -19,7 +19,6 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
-	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/tcpip"
@@ -135,6 +134,7 @@ func attachOrCreateNIC(s *stack.Stack, name, prefix string, linkCaps stack.LinkE
 
 		// 2. Creating a new NIC.
 		id := tcpip.NICID(s.UniqueID())
+		// TODO(gvisor.dev/1486): enable leak check for tunEndpoint.
 		endpoint := &tunEndpoint{
 			Endpoint: channel.New(defaultDevOutQueueLen, defaultDevMtu, ""),
 			stack:    s,
@@ -331,19 +331,18 @@ func (d *Device) WriteNotify() {
 // It is ref-counted as multiple opening files can attach to the same NIC.
 // The last owner is responsible for deleting the NIC.
 type tunEndpoint struct {
+	tunEndpointRefs
 	*channel.Endpoint
 
-	refs.AtomicRefCount
-
 	stack *stack.Stack
 	nicID tcpip.NICID
 	name  string
 	isTap bool
 }
 
-// DecRef decrements refcount of e, removes NIC if refcount goes to 0.
+// DecRef decrements refcount of e, removing NIC if it reaches 0.
 func (e *tunEndpoint) DecRef(ctx context.Context) {
-	e.DecRefWithDestructor(ctx, func(context.Context) {
+	e.tunEndpointRefs.DecRef(func() {
 		e.stack.RemoveNIC(e.nicID)
 	})
 }