2017-01-09 03:54:01

by Sriharsha Basavapatna

[permalink] [raw]
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]>
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



2017-01-09 06:42:37

by Yuval Shaia

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

On Mon, Jan 09, 2017 at 04:00:44PM +0530, Sriharsha Basavapatna 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;

Reviewed-by: Yuval Shaia <[email protected]>

> --
> 2.11.0.258.ge05806da9
>
> --
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2017-01-09 15:06:02

by Chuck Lever III

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


> On Jan 9, 2017, at 1:42 AM, Yuval Shaia <[email protected]> wrote:
>
> On Mon, Jan 09, 2017 at 04:00:44PM +0530, Sriharsha Basavapatna 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;
>
> Reviewed-by: Yuval Shaia <[email protected]>

Hi Bruce-

Is it possible to take this in v4.10-rc ?


--
Chuck Lever




2017-01-12 21:15:36

by J. Bruce Fields

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

On Mon, Jan 09, 2017 at 10:05:48AM -0500, Chuck Lever wrote:
>
> > On Jan 9, 2017, at 1:42 AM, Yuval Shaia <[email protected]> wrote:
> >
> > On Mon, Jan 09, 2017 at 04:00:44PM +0530, Sriharsha Basavapatna 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;
> >
> > Reviewed-by: Yuval Shaia <[email protected]>
>
> Hi Bruce-
>
> Is it possible to take this in v4.10-rc ?

Yep, thanks to all of you.--b.