[PATCH v2 net] ps3/gelic: Fix SKB allocation

[PATCH v2 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 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..3ebe903e4b6d 100644
--- a/drivers/net/ethernet/toshiba/ps3_gelic_net.c
+++ b/drivers/net/ethernet/toshiba/ps3_gelic_net.c
@@ -375,20 +375,15 @@ 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 +392,32 @@ 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 v2 net] ps3/gelic: Fix SKB allocation

[Jakub Kicinski]

On Mon, 5 Feb 2024 10:48:07 +0900 Geoff Levand wrote:
>     Commit 3ce4f9c3fbb3 ("net/ps3_gelic_net: Add gelic_descr structures")
>     of 6.8-rc1 did not set up the 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>

Please make the commit message describe the problem in more detail.
It's also indented for no reason.