Fix Commit a5d2f6f877 (contrib/rdmacm-mux: Add implementation
of RDMA User MAD multiplexer).
The above commit introduces a new contrib target, adding a global dependency
to libumad library in case pvrdma configuration option is enabled.
Clang forbids it:
clang-6.0: error: -libumad: 'linker' input unused
[-Werror,-Wunused-command-line-argument]
Fix by limiting the scope to the rdmacm-mux target itself.
Reported-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Tested-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20190118124614.24548-4-marcel.apfelbaum@gmail.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
The flag is not recognized by some CLANG versions.
Add proper constraints in code instead.
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Tested-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20190118124614.24548-2-marcel.apfelbaum@gmail.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
RDMA MAD kernel module (ibcm) disallow more than one MAD-agent for a
given MAD class.
This does not go hand-by-hand with qemu pvrdma device's requirements
where each VM is MAD agent.
Fix it by adding implementation of RDMA MAD multiplexer service which on
one hand register as a sole MAD agent with the kernel module and on the
other hand gives service to more than one VM.
Design Overview:
Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
----------------
A server process is registered to UMAD framework (for this to work the
rdma_cm kernel module needs to be unloaded) and creates a unix socket to
listen to incoming request from clients.
A client process (such as QEMU) connects to this unix socket and
registers with its own GID.
TX:
----
When client needs to send rdma_cm MAD message it construct it the same
way as without this multiplexer, i.e. creates a umad packet but this
time it writes its content to the socket instead of calling umad_send().
The server, upon receiving such a message fetch local_comm_id from it so
a context for this session can be maintain and relay the message to UMAD
layer by calling umad_send().
RX:
----
The server creates a worker thread to process incoming rdma_cm MAD
messages. When an incoming message arrived (umad_recv()) the server,
depending on the message type (attr_id) looks for target client by
either searching in gid->fd table or in local_comm_id->fd table. With
the extracted fd the server relays to incoming message to the client.
Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
