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authorGhanan Gowripalan <ghanan@google.com>2020-08-27 12:48:19 -0700
committergVisor bot <gvisor-bot@google.com>2020-08-27 12:50:19 -0700
commitdc81eb9c37873e391a927a6f6810239565a91732 (patch)
tree07629d5829f7598b9f4bb10219188162caf3a2ab /pkg/tcpip/transport/tcp/endpoint.go
parent01a35a2f193033e90af8ae49b22dc0cb70630d14 (diff)
Add function to get error from a tcpip.Endpoint
In an upcoming CL, socket option types are made to implement a marker interface with pointer receivers. Since this results in calling methods of an interface with a pointer, we incur an allocation when attempting to get an Endpoint's last error with the current implementation. When calling the method of an interface, the compiler is unable to determine what the interface implementation does with the pointer (since calling a method on an interface uses virtual dispatch at runtime so the compiler does not know what the interface method will do) so it allocates on the heap to be safe incase an implementation continues to hold the pointer after the functioon returns (the reference escapes the scope of the object). In the example below, the compiler does not know what b.foo does with the reference to a it allocates a on the heap as the reference to a may escape the scope of a. ``` var a int var b someInterface b.foo(&a) ``` This change removes the opportunity for that allocation. RELNOTES: n/a PiperOrigin-RevId: 328796559
Diffstat (limited to 'pkg/tcpip/transport/tcp/endpoint.go')
-rw-r--r--pkg/tcpip/transport/tcp/endpoint.go5
1 files changed, 1 insertions, 4 deletions
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index ff9b8804d..8a5e993b5 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -1234,7 +1234,7 @@ func (e *endpoint) SetOwner(owner tcpip.PacketOwner) {
e.owner = owner
}
-func (e *endpoint) takeLastError() *tcpip.Error {
+func (e *endpoint) LastError() *tcpip.Error {
e.lastErrorMu.Lock()
defer e.lastErrorMu.Unlock()
err := e.lastError
@@ -1995,9 +1995,6 @@ func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
// GetSockOpt implements tcpip.Endpoint.GetSockOpt.
func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
switch o := opt.(type) {
- case tcpip.ErrorOption:
- return e.takeLastError()
-
case *tcpip.BindToDeviceOption:
e.LockUser()
*o = tcpip.BindToDeviceOption(e.bindToDevice)