[PATCH] net: dma: use dmaengine_desc_set_callback()

[PATCH] net: dma: use dmaengine_desc_set_callback()

[Frank.Li]

From: Frank Li <Frank.Li@nxp.com>

Replace open-coded assignments to callback and callback_param fields
of struct dma_async_tx_descriptor with calls to the
dmaengine_desc_set_callback() helper across net drivers.

No functional change intended. Prepare to make struct
dma_async_tx_descriptor private to the DMA engine.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/net/ethernet/allwinner/sun4i-emac.c       |  3 +--
 drivers/net/ethernet/micrel/ks8842.c              |  6 ++----
 drivers/net/ethernet/xilinx/xilinx_axienet_main.c |  6 ++----
 drivers/net/wwan/qcom_bam_dmux.c                  | 10 ++++------
 4 files changed, 9 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/allwinner/sun4i-emac.c b/drivers/net/ethernet/allwinner/sun4i-emac.c
index 09b2abdfc9e84..d7ee42b2c1976 100644
--- a/drivers/net/ethernet/allwinner/sun4i-emac.c
+++ b/drivers/net/ethernet/allwinner/sun4i-emac.c
@@ -303,8 +303,7 @@ static int emac_dma_inblk_32bit(struct emac_board_info *db,
 		goto prepare_err;
 	}
 
-	desc->callback_param = req;
-	desc->callback = emac_dma_done_callback;
+	dmaengine_desc_set_callback(desc, emac_dma_done_callback, NULL, req);
 
 	cookie = dmaengine_submit(desc);
 	ret = dma_submit_error(cookie);
diff --git a/drivers/net/ethernet/micrel/ks8842.c b/drivers/net/ethernet/micrel/ks8842.c
index f0d6bfc6025ca..c68abd4643e72 100644
--- a/drivers/net/ethernet/micrel/ks8842.c
+++ b/drivers/net/ethernet/micrel/ks8842.c
@@ -453,8 +453,7 @@ static int ks8842_tx_frame_dma(struct sk_buff *skb, struct net_device *netdev)
 	if (!ctl->adesc)
 		return NETDEV_TX_BUSY;
 
-	ctl->adesc->callback_param = netdev;
-	ctl->adesc->callback = ks8842_dma_tx_cb;
+	dmaengine_desc_set_callback(ctl->adesc, ks8842_dma_tx_cb, NULL, netdev);
 	dmaengine_submit(ctl->adesc);
 
 	netdev->stats.tx_bytes += skb->len;
@@ -567,8 +566,7 @@ static int __ks8842_start_new_rx_dma(struct net_device *netdev)
 			goto out;
 		}
 
-		ctl->adesc->callback_param = netdev;
-		ctl->adesc->callback = ks8842_dma_rx_cb;
+		dmaengine_desc_set_callback(ctl->adesc, ks8842_dma_rx_cb, NULL, netdev);
 		dmaengine_submit(ctl->adesc);
 	} else {
 		err = -ENOMEM;
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 8a50cad1c104f..7e83c4b5f1931 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -1014,8 +1014,7 @@ axienet_start_xmit_dmaengine(struct sk_buff *skb, struct net_device *ndev)
 
 	skbuf_dma->skb = skb;
 	skbuf_dma->sg_len = sg_len;
-	dma_tx_desc->callback_param = lp;
-	dma_tx_desc->callback_result = axienet_dma_tx_cb;
+	dmaengine_desc_set_callback(dma_tx_desc, NULL, axienet_dma_tx_cb, lp);
 	/* Claim the ring slot only after the steps above that can fail.  The
 	 * completion callback can't run before dmaengine_submit().
 	 */
@@ -1565,8 +1564,7 @@ static void axienet_rx_submit_desc(struct net_device *ndev)
 	skbuf_dma->skb = skb;
 	skbuf_dma->dma_address = sg_dma_address(skbuf_dma->sgl);
 	skbuf_dma->desc = dma_rx_desc;
-	dma_rx_desc->callback_param = lp;
-	dma_rx_desc->callback_result = axienet_dma_rx_cb;
+	dmaengine_desc_set_callback(dma_rx_desc, NULL, axienet_dma_rx_cb, lp);
 	lp->rx_ring_head++;
 	dmaengine_submit(dma_rx_desc);
 
diff --git a/drivers/net/wwan/qcom_bam_dmux.c b/drivers/net/wwan/qcom_bam_dmux.c
index cc6ace8d64371..1479f8362e04e 100644
--- a/drivers/net/wwan/qcom_bam_dmux.c
+++ b/drivers/net/wwan/qcom_bam_dmux.c
@@ -195,9 +195,8 @@ static bool bam_dmux_skb_dma_submit_tx(struct bam_dmux_skb_dma *skb_dma)
 		return false;
 	}
 
-	desc->callback = bam_dmux_tx_callback;
-	desc->callback_param = skb_dma;
-	desc->cookie = dmaengine_submit(desc);
+	dmaengine_desc_set_callback(desc, bam_dmux_tx_callback, NULL, skb_dma);
+	dmaengine_submit(desc);
 	return true;
 }
 
@@ -477,9 +476,8 @@ static bool bam_dmux_skb_dma_submit_rx(struct bam_dmux_skb_dma *skb_dma)
 		return false;
 	}
 
-	desc->callback = bam_dmux_rx_callback;
-	desc->callback_param = skb_dma;
-	desc->cookie = dmaengine_submit(desc);
+	dmaengine_desc_set_callback(desc, bam_dmux_rx_callback, NULL, skb_dma);
+	dmaengine_submit(desc);
 	return true;
 }
 
-- 
2.43.0

Re: [PATCH] net: dma: use dmaengine_desc_set_callback()

[Joe Damato]

On Mon, Nov 02, 2026 at 02:19:16PM -0500, Frank.Li@oss.nxp.com wrote:
> From: Frank Li <Frank.Li@nxp.com>
> 
> Replace open-coded assignments to callback and callback_param fields
> of struct dma_async_tx_descriptor with calls to the
> dmaengine_desc_set_callback() helper across net drivers.
> 
> No functional change intended. Prepare to make struct
> dma_async_tx_descriptor private to the DMA engine.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>  drivers/net/ethernet/allwinner/sun4i-emac.c       |  3 +--
>  drivers/net/ethernet/micrel/ks8842.c              |  6 ++----
>  drivers/net/ethernet/xilinx/xilinx_axienet_main.c |  6 ++----
>  drivers/net/wwan/qcom_bam_dmux.c                  | 10 ++++------
>  4 files changed, 9 insertions(+), 16 deletions(-)

[...]

> diff --git a/drivers/net/wwan/qcom_bam_dmux.c b/drivers/net/wwan/qcom_bam_dmux.c
> index cc6ace8d64371..1479f8362e04e 100644
> --- a/drivers/net/wwan/qcom_bam_dmux.c
> +++ b/drivers/net/wwan/qcom_bam_dmux.c
> @@ -195,9 +195,8 @@ static bool bam_dmux_skb_dma_submit_tx(struct bam_dmux_skb_dma *skb_dma)
>  		return false;
>  	}
>  
> -	desc->callback = bam_dmux_tx_callback;
> -	desc->callback_param = skb_dma;
> -	desc->cookie = dmaengine_submit(desc);
> +	dmaengine_desc_set_callback(desc, bam_dmux_tx_callback, NULL, skb_dma);
> +	dmaengine_submit(desc);
>  	return true;
>  }
>  
> @@ -477,9 +476,8 @@ static bool bam_dmux_skb_dma_submit_rx(struct bam_dmux_skb_dma *skb_dma)
>  		return false;
>  	}
>  
> -	desc->callback = bam_dmux_rx_callback;
> -	desc->callback_param = skb_dma;
> -	desc->cookie = dmaengine_submit(desc);
> +	dmaengine_desc_set_callback(desc, bam_dmux_rx_callback, NULL, skb_dma);
> +	dmaengine_submit(desc);

I noticed in the above that the return value of dmaengine_submit is discarded
instead of stored.

Is that intentional? I suppose it might be because AFAICT cookie is never
used and the commit message says "no functional change intended".

Reviewed-by: Joe Damato <joe@dama.to>

Re: [PATCH] net: dma: use dmaengine_desc_set_callback()

[Loic Poulain]

On Mon, Nov 2, 2026 at 8:19 PM <Frank.Li@oss.nxp.com> wrote:
>
> From: Frank Li <Frank.Li@nxp.com>
>
> Replace open-coded assignments to callback and callback_param fields
> of struct dma_async_tx_descriptor with calls to the
> dmaengine_desc_set_callback() helper across net drivers.
>
> No functional change intended. Prepare to make struct
> dma_async_tx_descriptor private to the DMA engine.
>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>

Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>

> ---
>  drivers/net/ethernet/allwinner/sun4i-emac.c       |  3 +--
>  drivers/net/ethernet/micrel/ks8842.c              |  6 ++----
>  drivers/net/ethernet/xilinx/xilinx_axienet_main.c |  6 ++----
>  drivers/net/wwan/qcom_bam_dmux.c                  | 10 ++++------
>  4 files changed, 9 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/net/ethernet/allwinner/sun4i-emac.c b/drivers/net/ethernet/allwinner/sun4i-emac.c
> index 09b2abdfc9e84..d7ee42b2c1976 100644
> --- a/drivers/net/ethernet/allwinner/sun4i-emac.c
> +++ b/drivers/net/ethernet/allwinner/sun4i-emac.c
> @@ -303,8 +303,7 @@ static int emac_dma_inblk_32bit(struct emac_board_info *db,
>                 goto prepare_err;
>         }
>
> -       desc->callback_param = req;
> -       desc->callback = emac_dma_done_callback;
> +       dmaengine_desc_set_callback(desc, emac_dma_done_callback, NULL, req);
>
>         cookie = dmaengine_submit(desc);
>         ret = dma_submit_error(cookie);
> diff --git a/drivers/net/ethernet/micrel/ks8842.c b/drivers/net/ethernet/micrel/ks8842.c
> index f0d6bfc6025ca..c68abd4643e72 100644
> --- a/drivers/net/ethernet/micrel/ks8842.c
> +++ b/drivers/net/ethernet/micrel/ks8842.c
> @@ -453,8 +453,7 @@ static int ks8842_tx_frame_dma(struct sk_buff *skb, struct net_device *netdev)
>         if (!ctl->adesc)
>                 return NETDEV_TX_BUSY;
>
> -       ctl->adesc->callback_param = netdev;
> -       ctl->adesc->callback = ks8842_dma_tx_cb;
> +       dmaengine_desc_set_callback(ctl->adesc, ks8842_dma_tx_cb, NULL, netdev);
>         dmaengine_submit(ctl->adesc);
>
>         netdev->stats.tx_bytes += skb->len;
> @@ -567,8 +566,7 @@ static int __ks8842_start_new_rx_dma(struct net_device *netdev)
>                         goto out;
>                 }
>
> -               ctl->adesc->callback_param = netdev;
> -               ctl->adesc->callback = ks8842_dma_rx_cb;
> +               dmaengine_desc_set_callback(ctl->adesc, ks8842_dma_rx_cb, NULL, netdev);
>                 dmaengine_submit(ctl->adesc);
>         } else {
>                 err = -ENOMEM;
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> index 8a50cad1c104f..7e83c4b5f1931 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> @@ -1014,8 +1014,7 @@ axienet_start_xmit_dmaengine(struct sk_buff *skb, struct net_device *ndev)
>
>         skbuf_dma->skb = skb;
>         skbuf_dma->sg_len = sg_len;
> -       dma_tx_desc->callback_param = lp;
> -       dma_tx_desc->callback_result = axienet_dma_tx_cb;
> +       dmaengine_desc_set_callback(dma_tx_desc, NULL, axienet_dma_tx_cb, lp);
>         /* Claim the ring slot only after the steps above that can fail.  The
>          * completion callback can't run before dmaengine_submit().
>          */
> @@ -1565,8 +1564,7 @@ static void axienet_rx_submit_desc(struct net_device *ndev)
>         skbuf_dma->skb = skb;
>         skbuf_dma->dma_address = sg_dma_address(skbuf_dma->sgl);
>         skbuf_dma->desc = dma_rx_desc;
> -       dma_rx_desc->callback_param = lp;
> -       dma_rx_desc->callback_result = axienet_dma_rx_cb;
> +       dmaengine_desc_set_callback(dma_rx_desc, NULL, axienet_dma_rx_cb, lp);
>         lp->rx_ring_head++;
>         dmaengine_submit(dma_rx_desc);
>
> diff --git a/drivers/net/wwan/qcom_bam_dmux.c b/drivers/net/wwan/qcom_bam_dmux.c
> index cc6ace8d64371..1479f8362e04e 100644
> --- a/drivers/net/wwan/qcom_bam_dmux.c
> +++ b/drivers/net/wwan/qcom_bam_dmux.c
> @@ -195,9 +195,8 @@ static bool bam_dmux_skb_dma_submit_tx(struct bam_dmux_skb_dma *skb_dma)
>                 return false;
>         }
>
> -       desc->callback = bam_dmux_tx_callback;
> -       desc->callback_param = skb_dma;
> -       desc->cookie = dmaengine_submit(desc);
> +       dmaengine_desc_set_callback(desc, bam_dmux_tx_callback, NULL, skb_dma);
> +       dmaengine_submit(desc);
>         return true;
>  }
>
> @@ -477,9 +476,8 @@ static bool bam_dmux_skb_dma_submit_rx(struct bam_dmux_skb_dma *skb_dma)
>                 return false;
>         }
>
> -       desc->callback = bam_dmux_rx_callback;
> -       desc->callback_param = skb_dma;
> -       desc->cookie = dmaengine_submit(desc);
> +       dmaengine_desc_set_callback(desc, bam_dmux_rx_callback, NULL, skb_dma);
> +       dmaengine_submit(desc);
>         return true;
>  }
>
> --
> 2.43.0
>

Re: [PATCH] net: dma: use dmaengine_desc_set_callback()

[Frank Li]

On Mon, Nov 02, 2026 at 03:28:33PM -0800, Joe Damato wrote:
> On Mon, Nov 02, 2026 at 02:19:16PM -0500, Frank.Li@oss.nxp.com wrote:
> > From: Frank Li <Frank.Li@nxp.com>
> >
> > Replace open-coded assignments to callback and callback_param fields
> > of struct dma_async_tx_descriptor with calls to the
> > dmaengine_desc_set_callback() helper across net drivers.
> >
> > No functional change intended. Prepare to make struct
> > dma_async_tx_descriptor private to the DMA engine.
> >
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> >  drivers/net/ethernet/allwinner/sun4i-emac.c       |  3 +--
> >  drivers/net/ethernet/micrel/ks8842.c              |  6 ++----
> >  drivers/net/ethernet/xilinx/xilinx_axienet_main.c |  6 ++----
> >  drivers/net/wwan/qcom_bam_dmux.c                  | 10 ++++------
> >  4 files changed, 9 insertions(+), 16 deletions(-)
>
> [...]
>
> > diff --git a/drivers/net/wwan/qcom_bam_dmux.c b/drivers/net/wwan/qcom_bam_dmux.c
> > index cc6ace8d64371..1479f8362e04e 100644
> > --- a/drivers/net/wwan/qcom_bam_dmux.c
> > +++ b/drivers/net/wwan/qcom_bam_dmux.c
> > @@ -195,9 +195,8 @@ static bool bam_dmux_skb_dma_submit_tx(struct bam_dmux_skb_dma *skb_dma)
> >  		return false;
> >  	}
> >
> > -	desc->callback = bam_dmux_tx_callback;
> > -	desc->callback_param = skb_dma;
> > -	desc->cookie = dmaengine_submit(desc);
> > +	dmaengine_desc_set_callback(desc, bam_dmux_tx_callback, NULL, skb_dma);
> > +	dmaengine_submit(desc);
> >  	return true;
> >  }
> >
> > @@ -477,9 +476,8 @@ static bool bam_dmux_skb_dma_submit_rx(struct bam_dmux_skb_dma *skb_dma)
> >  		return false;
> >  	}
> >
> > -	desc->callback = bam_dmux_rx_callback;
> > -	desc->callback_param = skb_dma;
> > -	desc->cookie = dmaengine_submit(desc);
> > +	dmaengine_desc_set_callback(desc, bam_dmux_rx_callback, NULL, skb_dma);
> > +	dmaengine_submit(desc);
>
> I noticed in the above that the return value of dmaengine_submit is discarded
> instead of stored.
>
> Is that intentional? I suppose it might be because AFAICT cookie is never
> used and the commit message says "no functional change intended".

dma_cookie_assign() already set desc->cookie in dmaengine_submit(). Of couse
it is not obvious. Do you need me update commit message to descript it.

Frank

>
> Reviewed-by: Joe Damato <joe@dama.to>

Re: [PATCH] net: dma: use dmaengine_desc_set_callback()

[Joe Damato]

On Tue, Nov 03, 2026 at 09:06:03AM -0600, Frank Li wrote:
> On Mon, Nov 02, 2026 at 03:28:33PM -0800, Joe Damato wrote:
> > On Mon, Nov 02, 2026 at 02:19:16PM -0500, Frank.Li@oss.nxp.com wrote:
> > > From: Frank Li <Frank.Li@nxp.com>
> > >
> > > Replace open-coded assignments to callback and callback_param fields
> > > of struct dma_async_tx_descriptor with calls to the
> > > dmaengine_desc_set_callback() helper across net drivers.
> > >
> > > No functional change intended. Prepare to make struct
> > > dma_async_tx_descriptor private to the DMA engine.
> > >
> > > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > > ---
> > >  drivers/net/ethernet/allwinner/sun4i-emac.c       |  3 +--
> > >  drivers/net/ethernet/micrel/ks8842.c              |  6 ++----
> > >  drivers/net/ethernet/xilinx/xilinx_axienet_main.c |  6 ++----
> > >  drivers/net/wwan/qcom_bam_dmux.c                  | 10 ++++------
> > >  4 files changed, 9 insertions(+), 16 deletions(-)
> >
> > [...]
> >
> > > diff --git a/drivers/net/wwan/qcom_bam_dmux.c b/drivers/net/wwan/qcom_bam_dmux.c
> > > index cc6ace8d64371..1479f8362e04e 100644
> > > --- a/drivers/net/wwan/qcom_bam_dmux.c
> > > +++ b/drivers/net/wwan/qcom_bam_dmux.c
> > > @@ -195,9 +195,8 @@ static bool bam_dmux_skb_dma_submit_tx(struct bam_dmux_skb_dma *skb_dma)
> > >  		return false;
> > >  	}
> > >
> > > -	desc->callback = bam_dmux_tx_callback;
> > > -	desc->callback_param = skb_dma;
> > > -	desc->cookie = dmaengine_submit(desc);
> > > +	dmaengine_desc_set_callback(desc, bam_dmux_tx_callback, NULL, skb_dma);
> > > +	dmaengine_submit(desc);
> > >  	return true;
> > >  }
> > >
> > > @@ -477,9 +476,8 @@ static bool bam_dmux_skb_dma_submit_rx(struct bam_dmux_skb_dma *skb_dma)
> > >  		return false;
> > >  	}
> > >
> > > -	desc->callback = bam_dmux_rx_callback;
> > > -	desc->callback_param = skb_dma;
> > > -	desc->cookie = dmaengine_submit(desc);
> > > +	dmaengine_desc_set_callback(desc, bam_dmux_rx_callback, NULL, skb_dma);
> > > +	dmaengine_submit(desc);
> >
> > I noticed in the above that the return value of dmaengine_submit is discarded
> > instead of stored.
> >
> > Is that intentional? I suppose it might be because AFAICT cookie is never
> > used and the commit message says "no functional change intended".
> 
> dma_cookie_assign() already set desc->cookie in dmaengine_submit(). Of couse
> it is not obvious. Do you need me update commit message to descript it.

Ah, I see it now. In the tx_submit callback it looks like dma drivers set the
cookie.

So removing it here really is a no-op since it was getting set, as you said,
during submit.

My mistake. I don't think it's worth respinning just to fix the commit
message just because I didn't dig deep enough :)