2017-01-04 09:27:07

by Sriharsha Basavapatna

Subject: [PATCH] svcrdma: avoid duplicate dma unmapping during error recovery

In rdma_read_chunk_frmr() when ib_post_send() fails, the error code path
invokes ib_dma_unmap_sg() to unmap the sg list. It then invokes
svc_rdma_put_frmr() which in turn tries to unmap the same sg list through
ib_dma_unmap_sg() again. This second unmap is invalid and could lead to
problems when the iova being unmapped is subsequently reused. Remove
the call to unmap in rdma_read_chunk_frmr() and let svc_rdma_put_frmr()
handle it.

Fixes: 412a15c0fe53 ("svcrdma: Port to new memory registration API")
Cc: [email protected]
Signed-off-by: Sriharsha Basavapatna <[email protected]>
---
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 57d35fbb1c28..172b537f8cfc 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -347,8 +347,6 @@ int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
atomic_inc(&rdma_stat_read);
return ret;
err:
- ib_dma_unmap_sg(xprt->sc_cm_id->device,
- frmr->sg, frmr->sg_nents, frmr->direction);
svc_rdma_put_context(ctxt, 0);
svc_rdma_put_frmr(xprt, frmr);
return ret;
--
2.11.0.258.ge05806da9

2017-01-04 18:20:25

by Chuck Lever III

Subject: Re: [PATCH] svcrdma: avoid duplicate dma unmapping during error recovery

> On Jan 4, 2017, at 11:03 AM, Sriharsha Basavapatna <[email protected]> wrote:
>
> In rdma_read_chunk_frmr() when ib_post_send() fails, the error code path
> invokes ib_dma_unmap_sg() to unmap the sg list. It then invokes
> svc_rdma_put_frmr() which in turn tries to unmap the same sg list through
> ib_dma_unmap_sg() again. This second unmap is invalid and could lead to
> problems when the iova being unmapped is subsequently reused. Remove
> the call to unmap in rdma_read_chunk_frmr() and let svc_rdma_put_frmr()
> handle it.
>
> Fixes: 412a15c0fe53 ("svcrdma: Port to new memory registration API")
> Cc: [email protected]
> Signed-off-by: Sriharsha Basavapatna <[email protected]>

Reviewed-by: Chuck Lever <[email protected]>


> ---
> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> index 57d35fbb1c28..172b537f8cfc 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> @@ -347,8 +347,6 @@ int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
> atomic_inc(&rdma_stat_read);
> return ret;
> err:
> - ib_dma_unmap_sg(xprt->sc_cm_id->device,
> - frmr->sg, frmr->sg_nents, frmr->direction);
> svc_rdma_put_context(ctxt, 0);
> svc_rdma_put_frmr(xprt, frmr);
> return ret;
> --
> 2.11.0.258.ge05806da9
>
> --
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--
Chuck Lever