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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | AUTHOR | COLOPHON |
UMAD_RECV(3) OpenIB Programmer´s Manual UMAD_RECV(3)
umad_recv - receive umad
#include <infiniband/umad.h>
int umad_recv(int portid, void *umad, int *length, int timeout_ms);
umad_recv() waits up to timeout_ms milliseconds for an incoming MAD
message to be received from the port specified by portid.
A MAD "message" consists of a single MAD packet or a coalesced
multipacket RMPP transmission. In the RMPP case the header of the
first RMPP packet is returned as the header of the buffer and the
buffer data contains the coalesced data section of each subsequent
RMPP MAD packet within the transmission. Thus all the RMPP headers
except the first are not copied to user space from the kernel.
The message is copied to the umad buffer if there is sufficient room
and the received length is indicated. If the buffer is not large
enough, the size of the umad buffer needed is returned in length. A
negative timeout_ms makes the function block until a packet is
received. A timeout_ms parameter of zero indicates a non blocking
read.
Note length is a pointer to the length of the data portion of the
umad buffer. This means that umad must point to a buffer at least
umad_size() + *length bytes long.
Note also that *length must be >= 256 bytes. This length allows for
at least a single MAD packet to be returned.
umad_recv() on success return the agentid; on error, errno is set and
a negative value is returned as follows:
-EINVAL invalid port handle or agentid or *length is less than
the minimum supported
-EIO receive operation failed
-EWOULDBLOCK non blocking read can't be fulfilled
-ENOSPC The provided buffer is not long enough for the complete
message.
umad_poll(3)
Hal Rosenstock <halr@voltaire.com>
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 2020-08-13. (At
that time, the date of the most recent commit that was found in the
repository was 2020-08-05.) If you discover any rendering problems
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of the original manual page), send a mail to man-pages@man7.org
OpenIB May 11, 2007 UMAD_RECV(3)
Pages that refer to this page: umad_poll(3)