ibv_alloc_mw(3) — Linux manual page

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
       protection 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 function.

       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>

COLOPHON

       This page is part of the rdma-core (RDMA Core Userspace Libraries
       and Daemons) project.  Information about the project can be found
       at ⟨https://github.com/linux-rdma/rdma-core⟩.  If you have a bug
       report for this manual page, send it to
       linux-rdma@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository
       ⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2024-06-14.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2024-06-10.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

libibverbs                     2016-02-02                IBV_ALLOC_MW(3)

Pages that refer to this page: ibv_bind_mw(3)

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