[PATCH] forcedeth: Fix WARNINGS that result when DMA mapping is not checked

[PATCH] forcedeth: Fix WARNINGS that result when DMA mapping is not checked

[Larry Finger]

With 3.8-rc1, the first call of pci_map_single() that is not checked
with a corresponding pci_dma_mapping_error() call results in a warning
with a splat as follows:

WARNING: at lib/dma-debug.c:933 check_unmap+0x480/0x950()
Hardware name: HP Pavilion dv2700 Notebook PC
forcedeth 0000:00:0a.0: DMA-API: device driver failed to check
 map error[device address=0x00000000b176e002] [size=90 bytes] [mapped as single]

Signed-off-by: Larry Finger <Larry.Finger-tQ5ms3gMjBLk1uMJSBkQmQ@public.gmane.org>
---
 drivers/net/ethernet/nvidia/forcedeth.c |   23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
index 653487d..de39cf2 100644
--- a/drivers/net/ethernet/nvidia/forcedeth.c
+++ b/drivers/net/ethernet/nvidia/forcedeth.c
@@ -1821,6 +1821,11 @@ static int nv_alloc_rx(struct net_device *dev)
 							     skb->data,
 							     skb_tailroom(skb),
 							     PCI_DMA_FROMDEVICE);
+			if (pci_dma_mapping_error(np->pci_dev,
+						  np->put_rx_ctx->dma)) {
+				dev_kfree_skb_any(skb);
+				goto packet_dropped;
+			}
 			np->put_rx_ctx->dma_len = skb_tailroom(skb);
 			np->put_rx.orig->buf = cpu_to_le32(np->put_rx_ctx->dma);
 			wmb();
@@ -1830,6 +1835,7 @@ static int nv_alloc_rx(struct net_device *dev)
 			if (unlikely(np->put_rx_ctx++ == np->last_rx_ctx))
 				np->put_rx_ctx = np->first_rx_ctx;
 		} else {
+packet_dropped:
 			u64_stats_update_begin(&np->swstats_rx_syncp);
 			np->stat_rx_dropped++;
 			u64_stats_update_end(&np->swstats_rx_syncp);
@@ -1856,6 +1862,11 @@ static int nv_alloc_rx_optimized(struct net_device *dev)
 							     skb->data,
 							     skb_tailroom(skb),
 							     PCI_DMA_FROMDEVICE);
+			if (pci_dma_mapping_error(np->pci_dev,
+						  np->put_rx_ctx->dma)) {
+				dev_kfree_skb_any(skb);
+				goto packet_dropped;
+			}
 			np->put_rx_ctx->dma_len = skb_tailroom(skb);
 			np->put_rx.ex->bufhigh = cpu_to_le32(dma_high(np->put_rx_ctx->dma));
 			np->put_rx.ex->buflow = cpu_to_le32(dma_low(np->put_rx_ctx->dma));
@@ -1866,6 +1877,7 @@ static int nv_alloc_rx_optimized(struct net_device *dev)
 			if (unlikely(np->put_rx_ctx++ == np->last_rx_ctx))
 				np->put_rx_ctx = np->first_rx_ctx;
 		} else {
+packet_dropped:
 			u64_stats_update_begin(&np->swstats_rx_syncp);
 			np->stat_rx_dropped++;
 			u64_stats_update_end(&np->swstats_rx_syncp);
@@ -2217,6 +2229,9 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		bcnt = (size > NV_TX2_TSO_MAX_SIZE) ? NV_TX2_TSO_MAX_SIZE : size;
 		np->put_tx_ctx->dma = pci_map_single(np->pci_dev, skb->data + offset, bcnt,
 						PCI_DMA_TODEVICE);
+		if (pci_dma_mapping_error(np->pci_dev,
+					  np->put_tx_ctx->dma))
+			return NETDEV_TX_BUSY;
 		np->put_tx_ctx->dma_len = bcnt;
 		np->put_tx_ctx->dma_single = 1;
 		put_tx->buf = cpu_to_le32(np->put_tx_ctx->dma);
@@ -2337,6 +2352,9 @@ static netdev_tx_t nv_start_xmit_optimized(struct sk_buff *skb,
 		bcnt = (size > NV_TX2_TSO_MAX_SIZE) ? NV_TX2_TSO_MAX_SIZE : size;
 		np->put_tx_ctx->dma = pci_map_single(np->pci_dev, skb->data + offset, bcnt,
 						PCI_DMA_TODEVICE);
+		if (pci_dma_mapping_error(np->pci_dev,
+					  np->put_tx_ctx->dma))
+			return NETDEV_TX_BUSY;
 		np->put_tx_ctx->dma_len = bcnt;
 		np->put_tx_ctx->dma_single = 1;
 		put_tx->bufhigh = cpu_to_le32(dma_high(np->put_tx_ctx->dma));
@@ -5003,6 +5021,11 @@ static int nv_loopback_test(struct net_device *dev)
 	test_dma_addr = pci_map_single(np->pci_dev, tx_skb->data,
 				       skb_tailroom(tx_skb),
 				       PCI_DMA_FROMDEVICE);
+	if (pci_dma_mapping_error(np->pci_dev,
+				  test_dma_addr)) {
+		dev_kfree_skb_any(tx_skb);
+		goto out;
+	}
 	pkt_data = skb_put(tx_skb, pkt_len);
 	for (i = 0; i < pkt_len; i++)
 		pkt_data[i] = (u8)(i & 0xff);
-- 
1.7.10.4

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Re: [PATCH] forcedeth: Fix WARNINGS that result when DMA mapping is not checked

[Eric Dumazet]

On Thu, 2012-12-27 at 13:42 -0600, Larry Finger wrote:
> With 3.8-rc1, the first call of pci_map_single() that is not checked
> with a corresponding pci_dma_mapping_error() call results in a warning
> with a splat as follows:
> 
> WARNING: at lib/dma-debug.c:933 check_unmap+0x480/0x950()
> Hardware name: HP Pavilion dv2700 Notebook PC
> forcedeth 0000:00:0a.0: DMA-API: device driver failed to check
>  map error[device address=0x00000000b176e002] [size=90 bytes] [mapped as single]
> 
> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
> ---
>  drivers/net/ethernet/nvidia/forcedeth.c |   23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
> index 653487d..de39cf2 100644
> --- a/drivers/net/ethernet/nvidia/forcedeth.c
> +++ b/drivers/net/ethernet/nvidia/forcedeth.c
> @@ -1821,6 +1821,11 @@ static int nv_alloc_rx(struct net_device *dev)
>  							     skb->data,
>  							     skb_tailroom(skb),
>  							     PCI_DMA_FROMDEVICE);
> +			if (pci_dma_mapping_error(np->pci_dev,
> +						  np->put_rx_ctx->dma)) {
> +				dev_kfree_skb_any(skb);

skb has no destructor yet, kfree_skb(skb) should be fine

> +				goto packet_dropped;
> +			}
>  			np->put_rx_ctx->dma_len = skb_tailroom(skb);
>  			np->put_rx.orig->buf = cpu_to_le32(np->put_rx_ctx->dma);
>  			wmb();
> @@ -1830,6 +1835,7 @@ static int nv_alloc_rx(struct net_device *dev)
>  			if (unlikely(np->put_rx_ctx++ == np->last_rx_ctx))
>  				np->put_rx_ctx = np->first_rx_ctx;
>  		} else {
> +packet_dropped:
>  			u64_stats_update_begin(&np->swstats_rx_syncp);
>  			np->stat_rx_dropped++;
>  			u64_stats_update_end(&np->swstats_rx_syncp);
> @@ -1856,6 +1862,11 @@ static int nv_alloc_rx_optimized(struct net_device *dev)
>  							     skb->data,
>  							     skb_tailroom(skb),
>  							     PCI_DMA_FROMDEVICE);
> +			if (pci_dma_mapping_error(np->pci_dev,
> +						  np->put_rx_ctx->dma)) {
> +				dev_kfree_skb_any(skb);
> +				goto packet_dropped;
> +			}
>  			np->put_rx_ctx->dma_len = skb_tailroom(skb);
>  			np->put_rx.ex->bufhigh = cpu_to_le32(dma_high(np->put_rx_ctx->dma));
>  			np->put_rx.ex->buflow = cpu_to_le32(dma_low(np->put_rx_ctx->dma));
> @@ -1866,6 +1877,7 @@ static int nv_alloc_rx_optimized(struct net_device *dev)
>  			if (unlikely(np->put_rx_ctx++ == np->last_rx_ctx))
>  				np->put_rx_ctx = np->first_rx_ctx;
>  		} else {
> +packet_dropped:
>  			u64_stats_update_begin(&np->swstats_rx_syncp);
>  			np->stat_rx_dropped++;
>  			u64_stats_update_end(&np->swstats_rx_syncp);
> @@ -2217,6 +2229,9 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
>  		bcnt = (size > NV_TX2_TSO_MAX_SIZE) ? NV_TX2_TSO_MAX_SIZE : size;
>  		np->put_tx_ctx->dma = pci_map_single(np->pci_dev, skb->data + offset, bcnt,
>  						PCI_DMA_TODEVICE);
> +		if (pci_dma_mapping_error(np->pci_dev,
> +					  np->put_tx_ctx->dma))
> +			return NETDEV_TX_BUSY;

Really this is not going to work very well : caller will call this in a
loop.

>  		np->put_tx_ctx->dma_len = bcnt;
>  		np->put_tx_ctx->dma_single = 1;
>  		put_tx->buf = cpu_to_le32(np->put_tx_ctx->dma);
> @@ -2337,6 +2352,9 @@ static netdev_tx_t nv_start_xmit_optimized(struct sk_buff *skb,
>  		bcnt = (size > NV_TX2_TSO_MAX_SIZE) ? NV_TX2_TSO_MAX_SIZE : size;
>  		np->put_tx_ctx->dma = pci_map_single(np->pci_dev, skb->data + offset, bcnt,
>  						PCI_DMA_TODEVICE);
> +		if (pci_dma_mapping_error(np->pci_dev,
> +					  np->put_tx_ctx->dma))
> +			return NETDEV_TX_BUSY;

same problem here.

>  		np->put_tx_ctx->dma_len = bcnt;
>  		np->put_tx_ctx->dma_single = 1;
>  		put_tx->bufhigh = cpu_to_le32(dma_high(np->put_tx_ctx->dma));
> @@ -5003,6 +5021,11 @@ static int nv_loopback_test(struct net_device *dev)
>  	test_dma_addr = pci_map_single(np->pci_dev, tx_skb->data,
>  				       skb_tailroom(tx_skb),
>  				       PCI_DMA_FROMDEVICE);
> +	if (pci_dma_mapping_error(np->pci_dev,
> +				  test_dma_addr)) {
> +		dev_kfree_skb_any(tx_skb);

		kfree_skb(skb);

> +		goto out;
> +	}
>  	pkt_data = skb_put(tx_skb, pkt_len);
>  	for (i = 0; i < pkt_len; i++)
>  		pkt_data[i] = (u8)(i & 0xff);

Re: [PATCH] forcedeth: Fix WARNINGS that result when DMA mapping is not checked

[Larry Finger]

On 12/27/2012 02:05 PM, Eric Dumazet wrote:
> On Thu, 2012-12-27 at 13:42 -0600, Larry Finger wrote:
>> With 3.8-rc1, the first call of pci_map_single() that is not checked
>> with a corresponding pci_dma_mapping_error() call results in a warning
>> with a splat as follows:
>>
>> WARNING: at lib/dma-debug.c:933 check_unmap+0x480/0x950()
>> Hardware name: HP Pavilion dv2700 Notebook PC
>> forcedeth 0000:00:0a.0: DMA-API: device driver failed to check
>>   map error[device address=0x00000000b176e002] [size=90 bytes] [mapped as single]
>>
>> Signed-off-by: Larry Finger <Larry.Finger-tQ5ms3gMjBLk1uMJSBkQmQ@public.gmane.org>
>> ---
>>   drivers/net/ethernet/nvidia/forcedeth.c |   23 +++++++++++++++++++++++
>>   1 file changed, 23 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
>> index 653487d..de39cf2 100644
>> --- a/drivers/net/ethernet/nvidia/forcedeth.c
>> +++ b/drivers/net/ethernet/nvidia/forcedeth.c
>> @@ -1821,6 +1821,11 @@ static int nv_alloc_rx(struct net_device *dev)
>>   							     skb->data,
>>   							     skb_tailroom(skb),
>>   							     PCI_DMA_FROMDEVICE);
>> +			if (pci_dma_mapping_error(np->pci_dev,
>> +						  np->put_rx_ctx->dma)) {
>> +				dev_kfree_skb_any(skb);
>
> skb has no destructor yet, kfree_skb(skb) should be fine

OK.

>
>> +				goto packet_dropped;
>> +			}
>>   			np->put_rx_ctx->dma_len = skb_tailroom(skb);
>>   			np->put_rx.orig->buf = cpu_to_le32(np->put_rx_ctx->dma);
>>   			wmb();
>> @@ -1830,6 +1835,7 @@ static int nv_alloc_rx(struct net_device *dev)
>>   			if (unlikely(np->put_rx_ctx++ == np->last_rx_ctx))
>>   				np->put_rx_ctx = np->first_rx_ctx;
>>   		} else {
>> +packet_dropped:
>>   			u64_stats_update_begin(&np->swstats_rx_syncp);
>>   			np->stat_rx_dropped++;
>>   			u64_stats_update_end(&np->swstats_rx_syncp);
>> @@ -1856,6 +1862,11 @@ static int nv_alloc_rx_optimized(struct net_device *dev)
>>   							     skb->data,
>>   							     skb_tailroom(skb),
>>   							     PCI_DMA_FROMDEVICE);
>> +			if (pci_dma_mapping_error(np->pci_dev,
>> +						  np->put_rx_ctx->dma)) {
>> +				dev_kfree_skb_any(skb);
>> +				goto packet_dropped;
>> +			}
>>   			np->put_rx_ctx->dma_len = skb_tailroom(skb);
>>   			np->put_rx.ex->bufhigh = cpu_to_le32(dma_high(np->put_rx_ctx->dma));
>>   			np->put_rx.ex->buflow = cpu_to_le32(dma_low(np->put_rx_ctx->dma));
>> @@ -1866,6 +1877,7 @@ static int nv_alloc_rx_optimized(struct net_device *dev)
>>   			if (unlikely(np->put_rx_ctx++ == np->last_rx_ctx))
>>   				np->put_rx_ctx = np->first_rx_ctx;
>>   		} else {
>> +packet_dropped:
>>   			u64_stats_update_begin(&np->swstats_rx_syncp);
>>   			np->stat_rx_dropped++;
>>   			u64_stats_update_end(&np->swstats_rx_syncp);
>> @@ -2217,6 +2229,9 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
>>   		bcnt = (size > NV_TX2_TSO_MAX_SIZE) ? NV_TX2_TSO_MAX_SIZE : size;
>>   		np->put_tx_ctx->dma = pci_map_single(np->pci_dev, skb->data + offset, bcnt,
>>   						PCI_DMA_TODEVICE);
>> +		if (pci_dma_mapping_error(np->pci_dev,
>> +					  np->put_tx_ctx->dma))
>> +			return NETDEV_TX_BUSY;
>
> Really this is not going to work very well : caller will call this in a
> loop.

Any suggestions on what value should be returned, or does the caller need to be 
modified?

Thanks for the review,

Larry

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Re: [PATCH] forcedeth: Fix WARNINGS that result when DMA mapping is not checked

[Eric Dumazet]

On Thu, 2012-12-27 at 14:38 -0600, Larry Finger wrote:
> On 12/27/2012 02:05 PM, Eric Dumazet wrote:
> > On Thu, 2012-12-27 at 13:42 -0600, Larry Finger wrote:

> >> +		if (pci_dma_mapping_error(np->pci_dev,
> >> +					  np->put_tx_ctx->dma))
> >> +			return NETDEV_TX_BUSY;
> >
> > Really this is not going to work very well : caller will call this in a
> > loop.
> 
> Any suggestions on what value should be returned, or does the caller need to be 
> modified?

NETDEV_TX_BUSY is really obsolete

Documentation/networking/driver.txt

In case of mapping error, I would drop the packet.

(kfree_skb() it, increment a device tx_dropped counter,  and return
NETDEV_TX_OK)

Re: [PATCH] forcedeth: Fix WARNINGS that result when DMA mapping is not checked

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 27 Dec 2012 13:03:29 -0800

> On Thu, 2012-12-27 at 14:38 -0600, Larry Finger wrote:
>> On 12/27/2012 02:05 PM, Eric Dumazet wrote:
>> > On Thu, 2012-12-27 at 13:42 -0600, Larry Finger wrote:
> 
>> >> +		if (pci_dma_mapping_error(np->pci_dev,
>> >> +					  np->put_tx_ctx->dma))
>> >> +			return NETDEV_TX_BUSY;
>> >
>> > Really this is not going to work very well : caller will call this in a
>> > loop.
>> 
>> Any suggestions on what value should be returned, or does the caller need to be 
>> modified?
> 
> NETDEV_TX_BUSY is really obsolete
> 
> Documentation/networking/driver.txt
> 
> In case of mapping error, I would drop the packet.

Agreed.