| .\" -*- nroff -*- |
| .\" |
| .TH IBV_ALLOC_MW 3 2016-02-02 libibverbs "Libibverbs Programmer's Manual" |
| .SH "NAME" |
| ibv_alloc_mw, ibv_dealloc_mw \- allocate or deallocate a memory window (MW) |
| .SH "SYNOPSIS" |
| .nf |
| .B #include <infiniband/verbs.h> |
| .sp |
| .BI "struct ibv_mw *ibv_alloc_mw(struct ibv_pd " "*pd" , |
| .BI " enum ibv_mw_type " "type"); |
| .sp |
| .BI "int ibv_dealloc_mw(struct ibv_mw " "*mw" ); |
| .fi |
| .SH "DESCRIPTION" |
| .B ibv_alloc_mw() |
| allocates a memory window (MW) associated with the protection domain |
| .I pd\fR. |
| The MW's type (1 or 2A/2B) is |
| .I type\fR. |
| .PP |
| 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. |
| .PP |
| .B ibv_dealloc_mw() |
| Unbinds in case was previously bound and deallocates the MW |
| .I mw\fR. |
| .SH "RETURN VALUE" |
| .B ibv_alloc_mw() |
| returns a pointer to the allocated MW, or NULL if the request fails. |
| The remote key (\fBR_Key\fR) |
| field |
| .B 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 |
| .B rkey |
| as the rkey field of struct ibv_send_wr passed to the ibv_post_send function. |
| .PP |
| .B ibv_dealloc_mw() |
| returns 0 on success, or the value of errno on failure (which indicates the failure reason). |
| .SH "NOTES" |
| .B ibv_dereg_mr() |
| fails if any memory window is still bound to this MR. |
| .SH "SEE ALSO" |
| .BR ibv_alloc_pd (3), |
| .BR ibv_post_send (3), |
| .BR ibv_bind_mw (3), |
| .BR ibv_reg_mr (3), |
| .SH "AUTHORS" |
| .TP |
| Majd Dibbiny <majd@mellanox.com> |
| .TP |
| Yishai Hadas <yishaih@mellanox.com> |
