ibvdeallocpd

ibv_dealloc_pd is a function in the libibverbs library used to deallocate a Protection Domain (PD) within an InfiniBand or RDMA device. A PD serves as a container for resources such as queue pairs and memory regions, providing a scope for resource management and protection.

A PD must be valid at the time of deallocation. Before calling ibv_dealloc_pd, any resources attached to the PD, such as QPs or memory regions, should be detached or destroyed. If resources remain attached, the call may fail with an error such as EBUSY, leaving the PD allocated and potentially causing resource leaks.

The function prototype is int ibv_dealloc_pd(struct ibv_pd *pd); It returns 0 on success. On failure, it returns -1 and sets errno to indicate the error condition (for example, EBADF for an invalid PD or EBUSY if resources are still attached).

Typical usage patterns involve acquiring a device context, allocating a PD with ibv_alloc_pd, creating QPs or registering memory with that PD, and, when those resources are no longer needed, destroying or deregistering them before calling ibv_dealloc_pd. After deallocation, the PD handle becomes invalid and should not be used, and the device context can be closed with ibv_close_device.

See also libibverbs, ibv_alloc_pd, ibv_create_qp, and ibv_reg_mr for related resource management and common workflows in RDMA programming.