On 4/15/2019 4:47 PM, Collier, Josh D wrote:
-----Original Message-----
From: Tom Talpey [mailto:tom@xxxxxxxxxx]
Sent: Monday, April 15, 2019 3:15 PM
To: Dalessandro, Dennis <dennis.dalessandro@xxxxxxxxx>; jgg@xxxxxxxx;
dledford@xxxxxxxxxx
Cc: linux-rdma@xxxxxxxxxxxxxxx; Ruhl, Michael J <michael.j.ruhl@xxxxxxxxx>;
Marciniszyn, Mike <mike.marciniszyn@xxxxxxxxx>; Collier, Josh D
<josh.d.collier@xxxxxxxxx>; stable@xxxxxxxxxxxxxxx
Subject: Re: [PATCH for-rc] IB/rdmavt: Fix frwr memory registration
On 4/15/2019 2:34 PM, Dennis Dalessandro wrote:
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;
The above mr.length assignment is no longer needed, since it is
unconditionally overwritten several lines below.
The mr.length is still temporarily used by our rvt_set_page function effectively
as a page index and needs to continue to be initialized for that purpose.
Hmm, ok I guess. It seems quite odd to need to initialize it
to zero just to have it set by the callee to the proper value.
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;
Isn't this a redundant assignment? If it isn't, then why is the
mr->mr.offset not being recalculated?
The ib_mr iova can be changed by the ULP to any value, but any value should
index to the previously mapped MR's starting page and offset, hence those do
not change, and we only update the iova.
Ah, got it. The ULP changes iova between the map and the fastreg,
so the mr captures the fastreg value. Agreed.
Tom.
atomic_set(&mr->mr.lkey_invalid, 0);
return 0;
