io_uring Linked Requests Encode Dependency in Submission Order

Sat, 19 Sep 2026 00:00:00 +0000

An io_uring submission queue can contain many operations at once, but not every operation has to be independent. Setting IOSQE_IO_LINK on a submission queue entry binds it to the next entry, forming a chain in which execution order and failure propagation become part of the kernel-visible request structure.

That changes the contract compared with submitting two unrelated SQEs and coordinating them after completion. A linked chain expresses dependency before the kernel starts processing the operations. The distinction matters when a later request is valid only after an earlier request has completed, or when failure of one stage should prevent the remaining stages from running.

io_uring Links Serialize Dependent Requests

Fri, 18 Sep 2026 00:00:00 +0000

Two adjacent io_uring submission queue entries are normally independent requests. Setting IOSQE_IO_LINK on the first changes that relationship: the next request does not start before the linked request completes. Repeating the flag forms an ordered chain inside one submission batch.

The ordering property is narrower than global queue serialization. Requests outside the chain can still run independently, and separate chains can overlap. A link therefore expresses dependency between specific SQEs rather than imposing a barrier on the entire ring.

Asynchronous I/O on Nalar

io_uring Linked Requests Encode Dependency in Submission Order

io_uring Links Serialize Dependent Requests