ibv_alloc_dmah(3)
| ibv_alloc_dmah(3) | Libibverbs Programmer’s Manual | ibv_alloc_dmah(3) |
NAME
ibv_alloc_dmah - allocate a dma handle
int ibv_dealloc_dmah - deallocate a dma handle
SYNOPSIS
-
#include <infiniband/verbs.h> struct ibv_dmah *ibv_alloc_dmah(struct ibv_context *context, struct ibv_dmah_init_attr *attr); int ibv_dealloc_dmah(struct ibv_dmah *dmah);
DESCRIPTION
ibv_alloc_dmah() allocates an ibv_dmah object that is associated with the given context and the input attr parameter.
The allocated handle can be later used for optimizing DMA and RDMA operations associated with a registered memory region.
Once the ibv_dmah usage has been ended ibv_dealloc_dmah() should be called.
This call will release resources that were earlier allocated using the ibv_alloc_dmah() API.
ARGUMENTS
attr
-
enum ibv_tph_mem_type {
IBV_TPH_MEM_TYPE_VM, /* volatile memory */
IBV_TPH_MEM_TYPE_PM, /* persistent memory */ }; enum ibv_dmah_init_attr_mask {
IBV_DMAH_INIT_ATTR_MASK_CPU_ID = 1 << 0,
IBV_DMAH_INIT_ATTR_MASK_PH = 1 << 1,
IBV_DMAH_INIT_ATTR_MASK_TPH_MEM_TYPE = 1 << 2, }; struct ibv_dmah_init_attr {
uint32_t comp_mask; /* From ibv_dmah_init_attr_mask */
uint32_t cpu_id;
uint8_t ph;
uint8_t tph_mem_type; /* From enum ibv_tph_mem_type */ };
- comp_mask
- Bitmask specifying what fields in the structure are valid.
- cpu_id
- The cpu id that the dma handle refers to.
- ph
- Processing hints, used to aid in optimizing the handling of transactions over PCIe.
- tph_mem_type
- The target memory type, one among enum ibv_tph_mem_type.
RETURN VALUE
ibv_alloc_dmah() returns a pointer to the allocated dma handle object, or NULL if the request fails.
ibv_dealloc_dmah() returns 0 upon success, otherwise the errno value.
SEE ALSO
ibv_reg_mr_ex(3)
AUTHOR
Yishai Hadas yishaih@nvidia.com
| 2025-5-8 | libibverbs |