On 15/11/2015 23:10, Or Gerlitz wrote:
On Sun, Nov 15, 2015, Sagi Grimberg <sagig@xxxxxxxxxxxxxxxxxx> wrote:
On 15/11/2015 19:59, Christoph Hellwig wrote:
Without this sg_dma_len will return 0 on architectures tha have
the dma_length field.
and what wrong with that?
Because it's not length 0. It's because I did a (documented) hack
with the new memory registration API. I hope we can fix it soon.
Christoph, probably typo here? "tha" needs to be "that"
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/infiniband/ulp/srp/ib_srp.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c
b/drivers/infiniband/ulp/srp/ib_srp.c
index 32f7962..445c0a6 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1520,6 +1520,9 @@ static int srp_map_idb(struct srp_rdma_ch *ch,
struct srp_request *req,
state.sg_nents = 1;
sg_set_buf(idb_sg, req->indirect_desc, idb_len);
idb_sg->dma_address = req->indirect_dma_addr; /* hack! */
+#ifdef CONFIG_NEED_SG_DMA_LENGTH
+ idb_sg->dma_length = idb_sg->length; /* hack^2 */
+#endif
:)
We should really get this properly map/unmap per IO at some point.
Probably do it in both code paths...
Sagi, can you please elaborate a little further on the problem, srpt
WA,
It's srp initiator. This falls in the case where srp sends an indirect
buffer descriptor to the target (which is registered). For this
descriptor it uses a pre-dma-mapped buffer, so in order to fit it into
the new memory registration scheme (which works on SG lists), I hacked
a single entry SG and used the pre-dma-mapped address. What was missing
is the dma_length setting (because we didn't dma mapped the SG).
The proper fix is doing correct map/unmap per IO.
what do we do in isert and what is the proposed not WA solution?
iser does not have indirect buffer descriptors, only a single rkey
(per-direction).
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