[PATCH net] ps3/gelic: Fix SKB allocation

[PATCH net] ps3/gelic: Fix SKB allocation

[Geoff Levand]

Commit 3ce4f9c3fbb3 ("net/ps3_gelic_net: Add gelic_descr structures")
of 6.8-rc1 did not set up the ps3 gelic network SKB's correctly,
resulting in a kernel panic.
    
This fix changes the way the napi buffer and corresponding SKB are
allocated and managed.
    
Reported-by: sambat goson <sombat3960@gmail.com>
Fixes: 3ce4f9c3fbb3 ("net/ps3_gelic_net: Add gelic_descr structures")
Signed-off-by: Geoff Levand <geoff@infradead.org>

diff --git a/drivers/net/ethernet/toshiba/ps3_gelic_net.c b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
index d5b75af163d3..1870f173e850 100644
--- a/drivers/net/ethernet/toshiba/ps3_gelic_net.c
+++ b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
@@ -375,20 +375,16 @@ static int gelic_card_init_chain(struct gelic_card *card,
 static int gelic_descr_prepare_rx(struct gelic_card *card,
 				  struct gelic_descr *descr)
 {
-	static const unsigned int rx_skb_size =
-		ALIGN(GELIC_NET_MAX_FRAME, GELIC_NET_RXBUF_ALIGN) +
-		GELIC_NET_RXBUF_ALIGN - 1;
+	static const unsigned int napi_buff_size =
+		round_up(GELIC_NET_MAX_FRAME, GELIC_NET_RXBUF_ALIGN);
+
+	struct device *dev = ctodev(card);
 	dma_addr_t cpu_addr;
-	int offset;
+	void *napi_buff;
 
 	if (gelic_descr_get_status(descr) !=  GELIC_DESCR_DMA_NOT_IN_USE)
-		dev_info(ctodev(card), "%s: ERROR status\n", __func__);
+		dev_info(dev, "%s: ERROR status\n", __func__);
 
-	descr->skb = netdev_alloc_skb(*card->netdev, rx_skb_size);
-	if (!descr->skb) {
-		descr->hw_regs.payload.dev_addr = 0; /* tell DMAC don't touch memory */
-		return -ENOMEM;
-	}
 	descr->hw_regs.dmac_cmd_status = 0;
 	descr->hw_regs.result_size = 0;
 	descr->hw_regs.valid_size = 0;
@@ -397,24 +393,33 @@ static int gelic_descr_prepare_rx(struct gelic_card *card,
 	descr->hw_regs.payload.size = 0;
 	descr->skb = NULL;
 
-	offset = ((unsigned long)descr->skb->data) &
-		(GELIC_NET_RXBUF_ALIGN - 1);
-	if (offset)
-		skb_reserve(descr->skb, GELIC_NET_RXBUF_ALIGN - offset);
-	/* io-mmu-map the skb */
-	cpu_addr = dma_map_single(ctodev(card), descr->skb->data,
-				  GELIC_NET_MAX_FRAME, DMA_FROM_DEVICE);
-	descr->hw_regs.payload.dev_addr = cpu_to_be32(cpu_addr);
-	if (dma_mapping_error(ctodev(card), cpu_addr)) {
-		dev_kfree_skb_any(descr->skb);
+	napi_buff = napi_alloc_frag_align(napi_buff_size,
+		GELIC_NET_RXBUF_ALIGN);
+
+	if (unlikely(!napi_buff)) {
+		return -ENOMEM;
+	}
+
+	descr->skb = napi_build_skb(napi_buff, napi_buff_size);
+
+	if (unlikely(!descr->skb)) {
+		skb_free_frag(napi_buff);
+		return -ENOMEM;
+	}
+
+	cpu_addr = dma_map_single(dev, napi_buff, napi_buff_size,
+		DMA_FROM_DEVICE);
+
+	if (dma_mapping_error(dev, cpu_addr)) {
+		skb_free_frag(napi_buff);
 		descr->skb = NULL;
-		dev_info(ctodev(card),
-			 "%s:Could not iommu-map rx buffer\n", __func__);
+		dev_err_once(dev, "%s:Could not iommu-map rx buffer\n",
+			__func__);
 		gelic_descr_set_status(descr, GELIC_DESCR_DMA_NOT_IN_USE);
 		return -ENOMEM;
 	}
 
-	descr->hw_regs.payload.size = cpu_to_be32(GELIC_NET_MAX_FRAME);
+	descr->hw_regs.payload.size = cpu_to_be32(napi_buff_size);
 	descr->hw_regs.payload.dev_addr = cpu_to_be32(cpu_addr);
 
 	gelic_descr_set_status(descr, GELIC_DESCR_DMA_CARDOWNED);

Re: [PATCH net] ps3/gelic: Fix SKB allocation

[Paolo Abeni]

Hi,

On Fri, 2024-01-26 at 18:25 +0900, Geoff Levand wrote:
> Commit 3ce4f9c3fbb3 ("net/ps3_gelic_net: Add gelic_descr structures")
> of 6.8-rc1 did not set up the ps3 gelic network SKB's correctly,
> resulting in a kernel panic.
>     
> This fix changes the way the napi buffer and corresponding SKB are
> allocated and managed.
>     
> Reported-by: sambat goson <sombat3960@gmail.com>
> Fixes: 3ce4f9c3fbb3 ("net/ps3_gelic_net: Add gelic_descr structures")
> Signed-off-by: Geoff Levand <geoff@infradead.org>

The patch overall looks correct to me, but there are a few formal
issues worthy to be addressed, see below.

> 
> diff --git a/drivers/net/ethernet/toshiba/ps3_gelic_net.c b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
> index d5b75af163d3..1870f173e850 100644
> --- a/drivers/net/ethernet/toshiba/ps3_gelic_net.c
> +++ b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
> @@ -375,20 +375,16 @@ static int gelic_card_init_chain(struct gelic_card *card,
>  static int gelic_descr_prepare_rx(struct gelic_card *card,
>  				  struct gelic_descr *descr)
>  {
> -	static const unsigned int rx_skb_size =
> -		ALIGN(GELIC_NET_MAX_FRAME, GELIC_NET_RXBUF_ALIGN) +
> -		GELIC_NET_RXBUF_ALIGN - 1;
> +	static const unsigned int napi_buff_size =
> +		round_up(GELIC_NET_MAX_FRAME, GELIC_NET_RXBUF_ALIGN);
> +

No empty line in the declaration area.

> +	struct device *dev = ctodev(card);
>  	dma_addr_t cpu_addr;
> -	int offset;
> +	void *napi_buff;
>  
>  	if (gelic_descr_get_status(descr) !=  GELIC_DESCR_DMA_NOT_IN_USE)
> -		dev_info(ctodev(card), "%s: ERROR status\n", __func__);
> +		dev_info(dev, "%s: ERROR status\n", __func__);
>  
> -	descr->skb = netdev_alloc_skb(*card->netdev, rx_skb_size);
> -	if (!descr->skb) {
> -		descr->hw_regs.payload.dev_addr = 0; /* tell DMAC don't touch memory */
> -		return -ENOMEM;
> -	}
>  	descr->hw_regs.dmac_cmd_status = 0;
>  	descr->hw_regs.result_size = 0;
>  	descr->hw_regs.valid_size = 0;
> @@ -397,24 +393,33 @@ static int gelic_descr_prepare_rx(struct gelic_card *card,
>  	descr->hw_regs.payload.size = 0;
>  	descr->skb = NULL;
>  
> -	offset = ((unsigned long)descr->skb->data) &
> -		(GELIC_NET_RXBUF_ALIGN - 1);
> -	if (offset)
> -		skb_reserve(descr->skb, GELIC_NET_RXBUF_ALIGN - offset);
> -	/* io-mmu-map the skb */
> -	cpu_addr = dma_map_single(ctodev(card), descr->skb->data,
> -				  GELIC_NET_MAX_FRAME, DMA_FROM_DEVICE);
> -	descr->hw_regs.payload.dev_addr = cpu_to_be32(cpu_addr);
> -	if (dma_mapping_error(ctodev(card), cpu_addr)) {
> -		dev_kfree_skb_any(descr->skb);
> +	napi_buff = napi_alloc_frag_align(napi_buff_size,
> +		GELIC_NET_RXBUF_ALIGN);

Please align with the above bracket:

	napi_buff = napi_alloc_frag_align(napi_buff_size,
					  GELIC_NET_RXBUF_ALIGN);

> +
> +	if (unlikely(!napi_buff)) {
> +		return -ENOMEM;
> +	}

The brackets are not needed here.

> +
> +	descr->skb = napi_build_skb(napi_buff, napi_buff_size);
> +
> +	if (unlikely(!descr->skb)) {
> +		skb_free_frag(napi_buff);
> +		return -ENOMEM;
> +	}
> +
> +	cpu_addr = dma_map_single(dev, napi_buff, napi_buff_size,
> +		DMA_FROM_DEVICE);

Please align with the above bracket

> +
> +	if (dma_mapping_error(dev, cpu_addr)) {
> +		skb_free_frag(napi_buff);
>  		descr->skb = NULL;
> -		dev_info(ctodev(card),
> -			 "%s:Could not iommu-map rx buffer\n", __func__);
> +		dev_err_once(dev, "%s:Could not iommu-map rx buffer\n",
> +			__func__);

Same here.

Side note: as a nice net-next follow-up you could move the skb
allocation into gelic_net_pass_skb_up() - so that the skbuff is hot in
the cache at rx time.


Cheers,

Paolo

Re: [PATCH net] ps3/gelic: Fix SKB allocation

[Geoff Levand]

Hi Paolo,

On 1/30/24 21:37, Paolo Abeni wrote:
> Hi,
> 
> On Fri, 2024-01-26 at 18:25 +0900, Geoff Levand wrote:
>> Commit 3ce4f9c3fbb3 ("net/ps3_gelic_net: Add gelic_descr structures")
>> of 6.8-rc1 did not set up the ps3 gelic network SKB's correctly,
>> resulting in a kernel panic.
>>     
>> This fix changes the way the napi buffer and corresponding SKB are
>> allocated and managed.
>>     
>> Reported-by: sambat goson <sombat3960@gmail.com>
>> Fixes: 3ce4f9c3fbb3 ("net/ps3_gelic_net: Add gelic_descr structures")
>> Signed-off-by: Geoff Levand <geoff@infradead.org>
> 
> The patch overall looks correct to me, but there are a few formal
> issues worthy to be addressed, see below.

Thanks for the review.  I'll send out an updated patch sometime soon.

-Geoff