[PATCH net] bnx2x: use the right build_skb() helper

[PATCH net] bnx2x: use the right build_skb() helper

[Jakub Kicinski]

build_skb() no longer accepts slab buffers. Since slab use is fairly
uncommon we prefer the drivers to call a separate slab_build_skb()
function appropriately.

bnx2x uses the old semantics where size of 0 meant buffer from slab.
It sets the fp->rx_frag_size to 0 for MTUs which don't fit in a page.
It needs to call slab_build_skb().

This fixes the WARN_ONCE() of incorrect API use seen with bnx2x.

Reported-by: Thomas Voegtle <tv@lio96.de>
Link: https://lore.kernel.org/all/b8f295e4-ba57-8bfb-7d9c-9d62a498a727@lio96.de/
Fixes: ce098da1497c ("skbuff: Introduce slab_build_skb()")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: aelior@marvell.com
CC: skalluru@marvell.com
CC: manishc@marvell.com
CC: keescook@chromium.org
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 16c490692f42..12083b9679b5 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -672,6 +672,18 @@ static int bnx2x_fill_frag_skb(struct bnx2x *bp, struct bnx2x_fastpath *fp,
 	return 0;
 }
 
+static struct sk_buff *
+bnx2x_build_skb(const struct bnx2x_fastpath *fp, void *data)
+{
+	struct sk_buff *skb;
+
+	if (fp->rx_frag_size)
+		skb = build_skb(data, fp->rx_frag_size);
+	else
+		skb = slab_build_skb(data);
+	return skb;
+}
+
 static void bnx2x_frag_free(const struct bnx2x_fastpath *fp, void *data)
 {
 	if (fp->rx_frag_size)
@@ -779,7 +791,7 @@ static void bnx2x_tpa_stop(struct bnx2x *bp, struct bnx2x_fastpath *fp,
 	dma_unmap_single(&bp->pdev->dev, dma_unmap_addr(rx_buf, mapping),
 			 fp->rx_buf_size, DMA_FROM_DEVICE);
 	if (likely(new_data))
-		skb = build_skb(data, fp->rx_frag_size);
+		skb = bnx2x_build_skb(fp, data);
 
 	if (likely(skb)) {
 #ifdef BNX2X_STOP_ON_ERROR
@@ -1046,7 +1058,7 @@ static int bnx2x_rx_int(struct bnx2x_fastpath *fp, int budget)
 						 dma_unmap_addr(rx_buf, mapping),
 						 fp->rx_buf_size,
 						 DMA_FROM_DEVICE);
-				skb = build_skb(data, fp->rx_frag_size);
+				skb = bnx2x_build_skb(fp, data);
 				if (unlikely(!skb)) {
 					bnx2x_frag_free(fp, data);
 					bnx2x_fp_qstats(bp, fp)->
-- 
2.39.2

Re: [PATCH net] bnx2x: use the right build_skb() helper

[Leon Romanovsky]

On Tue, Mar 28, 2023 at 05:00:13PM -0700, Jakub Kicinski wrote:
> build_skb() no longer accepts slab buffers. Since slab use is fairly
> uncommon we prefer the drivers to call a separate slab_build_skb()
> function appropriately.
> 
> bnx2x uses the old semantics where size of 0 meant buffer from slab.
> It sets the fp->rx_frag_size to 0 for MTUs which don't fit in a page.
> It needs to call slab_build_skb().
> 
> This fixes the WARN_ONCE() of incorrect API use seen with bnx2x.
> 
> Reported-by: Thomas Voegtle <tv@lio96.de>
> Link: https://lore.kernel.org/all/b8f295e4-ba57-8bfb-7d9c-9d62a498a727@lio96.de/
> Fixes: ce098da1497c ("skbuff: Introduce slab_build_skb()")
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> CC: aelior@marvell.com
> CC: skalluru@marvell.com
> CC: manishc@marvell.com
> CC: keescook@chromium.org
> ---
>  drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

Re: [PATCH net] bnx2x: use the right build_skb() helper

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 28 Mar 2023 17:00:13 -0700 you wrote:
> build_skb() no longer accepts slab buffers. Since slab use is fairly
> uncommon we prefer the drivers to call a separate slab_build_skb()
> function appropriately.
> 
> bnx2x uses the old semantics where size of 0 meant buffer from slab.
> It sets the fp->rx_frag_size to 0 for MTUs which don't fit in a page.
> It needs to call slab_build_skb().
> 
> [...]

Here is the summary with links:
  - [net] bnx2x: use the right build_skb() helper
    https://git.kernel.org/netdev/net/c/8c495270845d

You are awesome, thank you!
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