Rust Replaces Legacy Binder Driver as Google Phases Out Old Code

Google has decided to retire its Binder C Linux driver, which was part of the mainline kernel as the inter-process communication (IPC) mechanism used on Android. The old Binder driver had been rewritten in Rust as one of the first 'real' drivers in the language, and now that it's matured enough, the C-based code is being phased out.

The new Rust Binder driver was upstreamed in Linux 6.18 and has proven to be easier to maintain and extend for new functionality. It has also shown competitive performance-wise with the original Binder driver, and in some cases, even beating it. Carlos Llamas, a Google engineer, wrote that the C driver had become 'painful to maintain' due to its growing complexity.

The removal of the old Binder driver is set for the upcoming Linux 7.4 kernel cycle. Alice Ryhl has worked hard on the Rust binder for the past couple of years and has achieved full feature parity with the C-based driver. The new driver has been running successfully on Android devices, making it time to 'move on' from the old code.

Greg Kroah-Hartman picked up this removal patch into the char-misc-next Git branch and is set to submit it for the Linux 7.4 merge window.