[PATCH 2.6.30] svcrdma: dma unmap the correct length for the RPCRDMA header page.

[PATCH 2.6.30] svcrdma: dma unmap the correct length for the RPCRDMA header page.

[Steve Wise]

The svcrdma module was incorrectly unmapping the RPCRDMA header page.
On IBM pserver systems this causes a resource leak that results in
running out of bus address space (10 cthon iterations will reproduce it).
The code was mapping the full page but only unmapping the actual header
length.  The fix is to only map the header length.

I also cleaned up the use of ib_dma_map_page() calls since the unmap
logic always uses ib_dma_unmap_single().  I made these symmetrical.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
---

 net/sunrpc/xprtrdma/svc_rdma_sendto.c    |   12 ++++++------
 net/sunrpc/xprtrdma/svc_rdma_transport.c |   10 +++++-----
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 8b510c5..f071b7e 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -128,7 +128,8 @@ static int fast_reg_xdr(struct svcxprt_rdma *xprt,
 		page_bytes -= sge_bytes;
 
 		frmr->page_list->page_list[page_no] =
-			ib_dma_map_page(xprt->sc_cm_id->device, page, 0,
+			ib_dma_map_single(xprt->sc_cm_id->device, 
+					  page_address(page),
 					  PAGE_SIZE, DMA_TO_DEVICE);
 		if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 					 frmr->page_list->page_list[page_no]))
@@ -532,18 +533,17 @@ static int send_reply(struct svcxprt_rdma *rdma,
 		clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
 
 	/* Prepare the SGE for the RPCRDMA Header */
+	ctxt->sge[0].lkey = rdma->sc_dma_lkey;
+	ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
 	ctxt->sge[0].addr =
-		ib_dma_map_page(rdma->sc_cm_id->device,
-				page, 0, PAGE_SIZE, DMA_TO_DEVICE);
+		ib_dma_map_single(rdma->sc_cm_id->device, page_address(page),
+				  ctxt->sge[0].length, DMA_TO_DEVICE);
 	if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
 		goto err;
 	atomic_inc(&rdma->sc_dma_used);
 
 	ctxt->direction = DMA_TO_DEVICE;
 
-	ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
-	ctxt->sge[0].lkey = rdma->sc_dma_lkey;
-
 	/* Determine how many of our SGE are to be transmitted */
 	for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
 		sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 4b0c2fa..5151f9f 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -500,8 +500,8 @@ int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
 		BUG_ON(sge_no >= xprt->sc_max_sge);
 		page = svc_rdma_get_page();
 		ctxt->pages[sge_no] = page;
-		pa = ib_dma_map_page(xprt->sc_cm_id->device,
-				     page, 0, PAGE_SIZE,
+		pa = ib_dma_map_single(xprt->sc_cm_id->device,
+				     page_address(page), PAGE_SIZE,
 				     DMA_FROM_DEVICE);
 		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
 			goto err_put_ctxt;
@@ -1315,8 +1315,8 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
 	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
 
 	/* Prepare SGE for local address */
-	sge.addr = ib_dma_map_page(xprt->sc_cm_id->device,
-				   p, 0, PAGE_SIZE, DMA_FROM_DEVICE);
+	sge.addr = ib_dma_map_single(xprt->sc_cm_id->device,
+				   page_address(p), PAGE_SIZE, DMA_FROM_DEVICE);
 	if (ib_dma_mapping_error(xprt->sc_cm_id->device, sge.addr)) {
 		put_page(p);
 		return;
@@ -1343,7 +1343,7 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
 	if (ret) {
 		dprintk("svcrdma: Error %d posting send for protocol error\n",
 			ret);
-		ib_dma_unmap_page(xprt->sc_cm_id->device,
+		ib_dma_unmap_single(xprt->sc_cm_id->device,
 				  sge.addr, PAGE_SIZE,
 				  DMA_FROM_DEVICE);
 		svc_rdma_put_context(ctxt, 1);

Re: [PATCH 2.6.30] svcrdma: dma unmap the correct length for the RPCRDMA header page.

[Steve Wise]

Hey Bruce,

Do you think this can make 2.6.30?

Thanks,

Steve.


Steve Wise wrote:
> The svcrdma module was incorrectly unmapping the RPCRDMA header page.
> On IBM pserver systems this causes a resource leak that results in
> running out of bus address space (10 cthon iterations will reproduce it).
> The code was mapping the full page but only unmapping the actual header
> length.  The fix is to only map the header length.
>
> I also cleaned up the use of ib_dma_map_page() calls since the unmap
> logic always uses ib_dma_unmap_single().  I made these symmetrical.
>
> Signed-off-by: Steve Wise <swise@opengridcomputing.com>
> Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
> ---
>
>  net/sunrpc/xprtrdma/svc_rdma_sendto.c    |   12 ++++++------
>  net/sunrpc/xprtrdma/svc_rdma_transport.c |   10 +++++-----
>  2 files changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> index 8b510c5..f071b7e 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> @@ -128,7 +128,8 @@ static int fast_reg_xdr(struct svcxprt_rdma *xprt,
>  		page_bytes -= sge_bytes;
>  
>  		frmr->page_list->page_list[page_no] =
> -			ib_dma_map_page(xprt->sc_cm_id->device, page, 0,
> +			ib_dma_map_single(xprt->sc_cm_id->device, 
> +					  page_address(page),
>  					  PAGE_SIZE, DMA_TO_DEVICE);
>  		if (ib_dma_mapping_error(xprt->sc_cm_id->device,
>  					 frmr->page_list->page_list[page_no]))
> @@ -532,18 +533,17 @@ static int send_reply(struct svcxprt_rdma *rdma,
>  		clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
>  
>  	/* Prepare the SGE for the RPCRDMA Header */
> +	ctxt->sge[0].lkey = rdma->sc_dma_lkey;
> +	ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
>  	ctxt->sge[0].addr =
> -		ib_dma_map_page(rdma->sc_cm_id->device,
> -				page, 0, PAGE_SIZE, DMA_TO_DEVICE);
> +		ib_dma_map_single(rdma->sc_cm_id->device, page_address(page),
> +				  ctxt->sge[0].length, DMA_TO_DEVICE);
>  	if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
>  		goto err;
>  	atomic_inc(&rdma->sc_dma_used);
>  
>  	ctxt->direction = DMA_TO_DEVICE;
>  
> -	ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
> -	ctxt->sge[0].lkey = rdma->sc_dma_lkey;
> -
>  	/* Determine how many of our SGE are to be transmitted */
>  	for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
>  		sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> index 4b0c2fa..5151f9f 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> @@ -500,8 +500,8 @@ int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
>  		BUG_ON(sge_no >= xprt->sc_max_sge);
>  		page = svc_rdma_get_page();
>  		ctxt->pages[sge_no] = page;
> -		pa = ib_dma_map_page(xprt->sc_cm_id->device,
> -				     page, 0, PAGE_SIZE,
> +		pa = ib_dma_map_single(xprt->sc_cm_id->device,
> +				     page_address(page), PAGE_SIZE,
>  				     DMA_FROM_DEVICE);
>  		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
>  			goto err_put_ctxt;
> @@ -1315,8 +1315,8 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
>  	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
>  
>  	/* Prepare SGE for local address */
> -	sge.addr = ib_dma_map_page(xprt->sc_cm_id->device,
> -				   p, 0, PAGE_SIZE, DMA_FROM_DEVICE);
> +	sge.addr = ib_dma_map_single(xprt->sc_cm_id->device,
> +				   page_address(p), PAGE_SIZE, DMA_FROM_DEVICE);
>  	if (ib_dma_mapping_error(xprt->sc_cm_id->device, sge.addr)) {
>  		put_page(p);
>  		return;
> @@ -1343,7 +1343,7 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
>  	if (ret) {
>  		dprintk("svcrdma: Error %d posting send for protocol error\n",
>  			ret);
> -		ib_dma_unmap_page(xprt->sc_cm_id->device,
> +		ib_dma_unmap_single(xprt->sc_cm_id->device,
>  				  sge.addr, PAGE_SIZE,
>  				  DMA_FROM_DEVICE);
>  		svc_rdma_put_context(ctxt, 1);
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>   

Re: [PATCH 2.6.30] svcrdma: dma unmap the correct length for the RPCRDMA header page.

[J. Bruce Fields]

On Tue, May 26, 2009 at 03:41:24PM -0500, Steve Wise wrote:
> Hey Bruce,
>
> Do you think this can make 2.6.30?

I was going to save it for 2.6.31; vague mental scorecard:

	- 2.6.30 is close to release
	- I think of rdma (correctly or not?) as a little young, so
	  don't prioritize bug-fixes to it quite as highly
	- A resource leak (even as large as this) isn't the worst
	  category of bug.

But I may be wrong.

--b.

>
> Thanks,
>
> Steve.
>
>
> Steve Wise wrote:
>> The svcrdma module was incorrectly unmapping the RPCRDMA header page.
>> On IBM pserver systems this causes a resource leak that results in
>> running out of bus address space (10 cthon iterations will reproduce it).
>> The code was mapping the full page but only unmapping the actual header
>> length.  The fix is to only map the header length.
>>
>> I also cleaned up the use of ib_dma_map_page() calls since the unmap
>> logic always uses ib_dma_unmap_single().  I made these symmetrical.
>>
>> Signed-off-by: Steve Wise <swise@opengridcomputing.com>
>> Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
>> ---
>>
>>  net/sunrpc/xprtrdma/svc_rdma_sendto.c    |   12 ++++++------
>>  net/sunrpc/xprtrdma/svc_rdma_transport.c |   10 +++++-----
>>  2 files changed, 11 insertions(+), 11 deletions(-)
>>
>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
>> index 8b510c5..f071b7e 100644
>> --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
>> +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
>> @@ -128,7 +128,8 @@ static int fast_reg_xdr(struct svcxprt_rdma *xprt,
>>  		page_bytes -= sge_bytes;
>>   		frmr->page_list->page_list[page_no] =
>> -			ib_dma_map_page(xprt->sc_cm_id->device, page, 0,
>> +			ib_dma_map_single(xprt->sc_cm_id->device, +					  
>> page_address(page),
>>  					  PAGE_SIZE, DMA_TO_DEVICE);
>>  		if (ib_dma_mapping_error(xprt->sc_cm_id->device,
>>  					 frmr->page_list->page_list[page_no]))
>> @@ -532,18 +533,17 @@ static int send_reply(struct svcxprt_rdma *rdma,
>>  		clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
>>   	/* Prepare the SGE for the RPCRDMA Header */
>> +	ctxt->sge[0].lkey = rdma->sc_dma_lkey;
>> +	ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
>>  	ctxt->sge[0].addr =
>> -		ib_dma_map_page(rdma->sc_cm_id->device,
>> -				page, 0, PAGE_SIZE, DMA_TO_DEVICE);
>> +		ib_dma_map_single(rdma->sc_cm_id->device, page_address(page),
>> +				  ctxt->sge[0].length, DMA_TO_DEVICE);
>>  	if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
>>  		goto err;
>>  	atomic_inc(&rdma->sc_dma_used);
>>   	ctxt->direction = DMA_TO_DEVICE;
>>  -	ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
>> -	ctxt->sge[0].lkey = rdma->sc_dma_lkey;
>> -
>>  	/* Determine how many of our SGE are to be transmitted */
>>  	for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
>>  		sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> index 4b0c2fa..5151f9f 100644
>> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> @@ -500,8 +500,8 @@ int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
>>  		BUG_ON(sge_no >= xprt->sc_max_sge);
>>  		page = svc_rdma_get_page();
>>  		ctxt->pages[sge_no] = page;
>> -		pa = ib_dma_map_page(xprt->sc_cm_id->device,
>> -				     page, 0, PAGE_SIZE,
>> +		pa = ib_dma_map_single(xprt->sc_cm_id->device,
>> +				     page_address(page), PAGE_SIZE,
>>  				     DMA_FROM_DEVICE);
>>  		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
>>  			goto err_put_ctxt;
>> @@ -1315,8 +1315,8 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
>>  	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
>>   	/* Prepare SGE for local address */
>> -	sge.addr = ib_dma_map_page(xprt->sc_cm_id->device,
>> -				   p, 0, PAGE_SIZE, DMA_FROM_DEVICE);
>> +	sge.addr = ib_dma_map_single(xprt->sc_cm_id->device,
>> +				   page_address(p), PAGE_SIZE, DMA_FROM_DEVICE);
>>  	if (ib_dma_mapping_error(xprt->sc_cm_id->device, sge.addr)) {
>>  		put_page(p);
>>  		return;
>> @@ -1343,7 +1343,7 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
>>  	if (ret) {
>>  		dprintk("svcrdma: Error %d posting send for protocol error\n",
>>  			ret);
>> -		ib_dma_unmap_page(xprt->sc_cm_id->device,
>> +		ib_dma_unmap_single(xprt->sc_cm_id->device,
>>  				  sge.addr, PAGE_SIZE,
>>  				  DMA_FROM_DEVICE);
>>  		svc_rdma_put_context(ctxt, 1);
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>   
>

Re: [PATCH 2.6.30] svcrdma: dma unmap the correct length for the RPCRDMA header page.

[Steve Wise]

J. Bruce Fields wrote:
> On Tue, May 26, 2009 at 03:41:24PM -0500, Steve Wise wrote:
>   
>> Hey Bruce,
>>
>> Do you think this can make 2.6.30?
>>     
>
> I was going to save it for 2.6.31; vague mental scorecard:
>
> 	- 2.6.30 is close to release
> 	- I think of rdma (correctly or not?) as a little young, so
> 	  don't prioritize bug-fixes to it quite as highly
> 	- A resource leak (even as large as this) isn't the worst
> 	  category of bug.
>
> But I may be wrong.
>
>   
Ok.

As a data point: this bug will exhaust the iommu address space on a IBM 
Power system within 10 cthon iterations...

Steve.

Re: [PATCH 2.6.30] svcrdma: dma unmap the correct length for the RPCRDMA header page.

[J. Bruce Fields]

On Tue, May 26, 2009 at 05:09:15PM -0500, Steve Wise wrote:
> J. Bruce Fields wrote:
>> On Tue, May 26, 2009 at 03:41:24PM -0500, Steve Wise wrote:
>>   
>>> Hey Bruce,
>>>
>>> Do you think this can make 2.6.30?
>>>     
>>
>> I was going to save it for 2.6.31; vague mental scorecard:
>>
>> 	- 2.6.30 is close to release
>> 	- I think of rdma (correctly or not?) as a little young, so
>> 	  don't prioritize bug-fixes to it quite as highly
>> 	- A resource leak (even as large as this) isn't the worst
>> 	  category of bug.
>>
>> But I may be wrong.
>>
>>   
> Ok.
>
> As a data point: this bug will exhaust the iommu address space on a IBM  
> Power system within 10 cthon iterations...

OK.  I may get this in for 2.6.30.

--b.