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authorChuck Lever2020-02-12 11:12:30 -0500
committerAnna Schumaker2020-02-13 15:35:33 -0500
commitca1c671302825182629d3c1a60363cee6f5455bb (patch)
tree3d73e0b5bab64840f7c824f8469ec9464a99e12a /net/sunrpc
parentefeda80da38d0b4afd77a12bd4a44f657567d26c (diff)
xprtrdma: Fix DMA scatter-gather list mapping imbalance
The @nents value that was passed to ib_dma_map_sg() has to be passed to the matching ib_dma_unmap_sg() call. If ib_dma_map_sg() choses to concatenate sg entries, it will return a different nents value than it was passed. The bug was exposed by recent changes to the AMD IOMMU driver, which enabled sg entry concatenation. Looking all the way back to commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API") and reviewing other kernel ULPs, it's not clear that the frwr_map() logic was ever correct for this case. Reported-by: Andre Tomt <andre@tomt.net> Suggested-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: stable@vger.kernel.org Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/xprtrdma/frwr_ops.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index 095be887753e..125297c9aa3e 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -288,8 +288,8 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
struct ib_reg_wr *reg_wr;
+ int i, n, dma_nents;
struct ib_mr *ibmr;
- int i, n;
u8 key;
if (nsegs > ia->ri_max_frwr_depth)
@@ -313,15 +313,16 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
break;
}
mr->mr_dir = rpcrdma_data_dir(writing);
+ mr->mr_nents = i;
- mr->mr_nents =
- ib_dma_map_sg(ia->ri_id->device, mr->mr_sg, i, mr->mr_dir);
- if (!mr->mr_nents)
+ dma_nents = ib_dma_map_sg(ia->ri_id->device, mr->mr_sg, mr->mr_nents,
+ mr->mr_dir);
+ if (!dma_nents)
goto out_dmamap_err;
ibmr = mr->frwr.fr_mr;
- n = ib_map_mr_sg(ibmr, mr->mr_sg, mr->mr_nents, NULL, PAGE_SIZE);
- if (unlikely(n != mr->mr_nents))
+ n = ib_map_mr_sg(ibmr, mr->mr_sg, dma_nents, NULL, PAGE_SIZE);
+ if (n != dma_nents)
goto out_mapmr_err;
ibmr->iova &= 0x00000000ffffffff;