On Mon, Aug 03, 2015 at 11:33:51AM -0700, Bart Van Assche wrote:
> >Bart, do you know what hardware this workaround is for?
>
> I hope the HW vendors can comment on this. Sorry but I'm not sure which HCA
> models and/or firmware versions do not support FMR mapping with a non-zero
> offset.
Perhaps David can remember why he added this:
commit 8f26c9ff9cd0317ad867bce972f69e0c6c2cbe3c
IB/srp: rework mapping engine to use multiple FMR entries
+ /* If we start at an offset into the FMR page, don't merge into
+ * the current FMR. Finish it out, and use the kernel's MR for this
+ * sg entry. This is to avoid potential bugs on some SRP targets
+ * that were never quite defined, but went away when the initiator
+ * avoided using FMR on such page fragments.
+ */
+ if (dma_addr & ~dev->fmr_page_mask || dma_len > dev->fmr_max_size) {
+ ret = srp_map_finish_fmr(state, target);
+ if (ret)
+ return ret;
+
+ srp_map_desc(state, dma_addr, dma_len, target->rkey);
+ srp_map_update_start(state, NULL, 0, 0);
+ return 0;
}
The way it is phrased makes it seem like a target bug, not a HCA bug?
Jason
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