IBV_ALLOC_MW(3) Libibverbs Programmer's Manual IBV_ALLOC_MW(3)
NAME
ibv_alloc_mw, ibv_dealloc_mw - allocate or deallocate a memory window
(MW)
SYNOPSIS
#include <infiniband/verbs.h>
struct ibv_mw *ibv_alloc_mw(struct ibv_pd *pd,
enum ibv_mw_type type);
int ibv_dealloc_mw(struct ibv_mw *mw);
DESCRIPTION
ibv_alloc_mw() allocates a memory window (MW) associated with the pro-
tection domain pd. The MW's type (1 or 2A/2B) is type.
The MW is created not bound. For it to be useful, the MW must be bound,
through either ibv_bind_mw (type 1) or a special WR (type 2). Once
bound, the memory window allows RDMA (remote) access to a subset of the
MR to which it was bound, until invalidated by: ibv_bind_mw verb with
zero length for type 1, IBV_WR_LOCAL_INV/IBV_WR_SEND_WITH_INV WR opcode
for type 2, deallocation.
ibv_dealloc_mw() Unbinds in case was previously bound and deallocates
the MW mw.
RETURN VALUE
ibv_alloc_mw() returns a pointer to the allocated MW, or NULL if the
request fails. The remote key (R_Key) field rkey is used by remote
processes to perform Atomic and RDMA operations. This key will be
changed during bind operations. The remote process places this rkey as
the rkey field of struct ibv_send_wr passed to the ibv_post_send func-
tion.
ibv_dealloc_mw() returns 0 on success, or the value of errno on failure
(which indicates the failure reason).
NOTES
ibv_dereg_mr() fails if any memory window is still bound to this MR.
SEE ALSO
ibv_alloc_pd(3), ibv_post_send(3), ibv_bind_mw(3), ibv_reg_mr(3),
AUTHORS
Majd Dibbiny <majd@mellanox.com>
Yishai Hadas <yishaih@mellanox.com>
libibverbs 2016-02-02 IBV_ALLOC_MW(3)
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