[$] The "rnull" Rust block driver

Andreas Hindborg has submitted a patch set to the Linux kernel implementing the 'rnull' Rust block driver, bringing it to feature parity with the C-based null_blk driver used for benchmarking block-layer implementations. The patch set, shared in June 2026, demonstrates that a simple block driver can now be written using the kernel's Rust APIs and enables direct performance comparisons between the C and Rust versions.

The null block driver https://www.kernel.org/doc/html/latest/block/null blk.html null blk is a small driver that is mostly useful for benchmarking block-layer implementations. It accepts all requests and marks them complete as quickly as possible, doing as little work as possible. In June 2026, Andreas Hindborg shared a patch set https://lwn.net/ml/all/20260609-rnull-v6-19-rc5-send-v2-0-82c7404542e2@kernel.org/ implementing the same functionality in Rust, in order to show that a simple block driver is now possible to write using the kernel's Rust APIs and to enable comparisons between the C and Rust implementations. A minimal version of the "rnull" driver is already present in the mainline kernel, but Hindborg's patch set brings it up to feature parity with the C version.