A storage controller of a data storage system maintains, for each interrupt vector, (1) a pending status that indicates whether one or more completions are pending in the completion queue (CQ) associated with the interrupt vector, and (2) an in-progress status that indicates whether or not the storage controller is currently in the process of composing an interrupt. The storage controller utilizes these two statuses to reduce or eliminate spurious interrupts by preventing an interrupt from being composed if there are no completions in the CQ, by preventing an interrupt from being composed if the corresponding interrupt mask has been set before composition of the interrupt begins, and by preventing an interrupt from being sent to the host system in cases where the interrupt mask was set after composition of the interrupt began, but before the interrupt has been sent to the host system.