Re: [PATCH 09/11] IB/srpt: convert to the generic RDMA READ/WRITE API

[Bart Van Assche <bart.vanassche@sandisk.com>]

On 05/03/2016 09:01 AM, Christoph Hellwig wrote:
> Replace the homegrown RDMA READ/WRITE code in srpt with the generic API.
> The only real twist here is that we need to allocate one Linux scatterlist
> per direct buffer in the SRP command, and chain them before handing them
> off to the target core.
>
> As a side-effect of the conversion the driver will also chain the SEND
> of the SRP response to the RDMA WRITE WRs for a DATA OUT command, and
> properly account for RDMA WRITE WRs instead of just for RDMA READ WRs
> like the driver previously did.
>
> We now allocate half of the SQ size to RDMA READ/WRITE contexts, assuming
> by default one RDMA READ or WRITE operation per command.  If a command
> has multiple operations it will eat into the budget but will still succeed,
> possible after waiting for WQEs to be available.
>
> Also ensure the QPs request the maximum allowed SGEs so that RDMA R/W API
> works correctly.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>