[PATCH for-rc] IB/rdmavt: Fix frwr memory registration

[Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>]

From: Josh Collier <josh.d.collier@xxxxxxxxx>

Current implementation was not properly handling frwr memory
registrations. This was uncovered by:
  commit 27f26cec761das
  xprtrdma: Plant XID in on-the-wire RDMA offset (FRWR)
in which xprtrdma, which is used for NFS over RDMA, started
failing as it was the first ULP to modify the ib_mr iova
resulting in the NFS server getting REMOTE ACCESS ERROR
when attempting to perform RDMA Writes to the client.

The fix is to properly capture the true iova, offset, and length
in the call to ib_map_mr_sg, and then update the iova when
processing the IB_WR_REG_MEM on the send queue.

Fixes: a41081aa5936 ("IB/rdmavt: Add support for ib_map_mr_sg")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
Signed-off-by: Josh Collier <josh.d.collier@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
---
 drivers/infiniband/sw/rdmavt/mr.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/sw/rdmavt/mr.c b/drivers/infiniband/sw/rdmavt/mr.c
index 7287950..0bb6e39 100644
--- a/drivers/infiniband/sw/rdmavt/mr.c
+++ b/drivers/infiniband/sw/rdmavt/mr.c
@@ -608,11 +608,6 @@ static int rvt_set_page(struct ib_mr *ibmr, u64 addr)
 	if (unlikely(mapped_segs == mr->mr.max_segs))
 		return -ENOMEM;
 
-	if (mr->mr.length == 0) {
-		mr->mr.user_base = addr;
-		mr->mr.iova = addr;
-	}
-
 	m = mapped_segs / RVT_SEGSZ;
 	n = mapped_segs % RVT_SEGSZ;
 	mr->mr.map[m]->segs[n].vaddr = (void *)addr;
@@ -630,17 +625,24 @@ static int rvt_set_page(struct ib_mr *ibmr, u64 addr)
  * @sg_nents: number of entries in sg
  * @sg_offset: offset in bytes into sg
  *
+ * Overwrite rvt_mr length with mr length calculated by ib_sg_to_pages.
+ *
  * Return: number of sg elements mapped to the memory region
  */
 int rvt_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sg,
 		  int sg_nents, unsigned int *sg_offset)
 {
 	struct rvt_mr *mr = to_imr(ibmr);
+	int ret;
 
 	mr->mr.length = 0;
 	mr->mr.page_shift = PAGE_SHIFT;
-	return ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset,
-			      rvt_set_page);
+	ret = ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, rvt_set_page);
+	mr->mr.user_base = ibmr->iova;
+	mr->mr.iova = ibmr->iova;
+	mr->mr.offset = ibmr->iova - (u64)mr->mr.map[0]->segs[0].vaddr;
+	mr->mr.length = (size_t)ibmr->length;
+	return ret;
 }
 
 /**
@@ -671,6 +673,7 @@ int rvt_fast_reg_mr(struct rvt_qp *qp, struct ib_mr *ibmr, u32 key,
 	ibmr->rkey = key;
 	mr->mr.lkey = key;
 	mr->mr.access_flags = access;
+	mr->mr.iova = ibmr->iova;
 	atomic_set(&mr->mr.lkey_invalid, 0);
 
 	return 0;