On Tue, Mar 08, 2016 at 01:32:44PM -0800, Bart Van Assche wrote:
> The above pr_info() message does not provide enough context information to
> allow a user to figure out why that message was reported. Please leave that
> message out and make the callers of this function report MR allocation
> failure wherever useful.
Ok, I'll remove it.
>> + ret = ib_map_mr_sg(reg->mr, sg, nents, offset,
>> + PAGE_SIZE);
> [ ... ]
>> + sg = sg_next(sg);
>
> ib_map_mr_sg() processed 'ret' elements of scatterlist 'sg'. So why is 'sg'
> only advanced by one element at the end of the loop?
I think the multiple MR case here is simply broken, as we never hit
for the iSER or NVMe over Fabrics I/O sizes. I think the safest
is to simply not allow for it. I'll update the patch to disable the
loop, and add a helper for the driver to query the max I/O size
supported by the device.
>> + for (j = 0; j < nr_sge; j++, sg = sg_next(sg)) {
>> + rdma_wr->wr.num_sge++;
>> +
>> + sge->addr = ib_sg_dma_address(dev, sg) + offset;
>> + sge->length = ib_sg_dma_len(dev, sg) - offset;
>> + sge->lkey = qp->pd->local_dma_lkey;
>> +
>> + total_len += sge->length;
>> + sge++;
>> + sge_left--;
>> + offset = 0;
>> + }
>
> Shouldn't there be a break statement in the above loop that stops this loop
> if the end of the sg list has been reached? Less than nr_sge iterations
> will be needed to reach the end of the sg list if the length of the sg list
> is not a multiple of nr_sge.
nr_sge is calculated as:
u32 nr_sge = min(sge_left, max_sge);
so it will never contain more iteration than we can possibly do.
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