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[RFC PATCH 3/5] staging: vt6655: split device_alloc_rx_buf

Nam Cao posted 5 patches 3 years, 6 months ago
There is a newer version of this series
[RFC PATCH 3/5] staging: vt6655: split device_alloc_rx_buf
Posted by Nam Cao 3 years, 6 months ago 
The function device_alloc_rx_buf does 2 things: allocating rx buffer
and initializing the rx descriptor's values. Split this function into
two, with each does one job.

This split is preparation for implementing correct out-of-memory error
handling.

Signed-off-by: Nam Cao <namcaov@gmail.com>
---
 drivers/staging/vt6655/device_main.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index 79325a693857..27fe28156257 100644
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -133,6 +133,7 @@ static int device_init_td1_ring(struct vnt_private *priv);
 static int  device_rx_srv(struct vnt_private *priv, unsigned int idx);
 static int  device_tx_srv(struct vnt_private *priv, unsigned int idx);
 static bool device_alloc_rx_buf(struct vnt_private *, struct vnt_rx_desc *);
+static void device_init_rx_desc(struct vnt_private *priv, struct vnt_rx_desc *rd);
 static void device_free_rx_buf(struct vnt_private *priv,
 			       struct vnt_rx_desc *rd);
 static void device_init_registers(struct vnt_private *priv);
@@ -615,6 +616,8 @@ static int device_init_rd0_ring(struct vnt_private *priv)
 			dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
 			ret = -ENOMEM;
 			goto err_free_rd;
+		} else {
+			device_init_rx_desc(priv, desc);
 		}
 
 		desc->next = &priv->aRD0Ring[(i + 1) % priv->opts.rx_descs0];
@@ -661,6 +664,8 @@ static int device_init_rd1_ring(struct vnt_private *priv)
 			dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
 			ret = -ENOMEM;
 			goto err_free_rd;
+		} else {
+			device_init_rx_desc(priv, desc);
 		}
 
 		desc->next = &priv->aRD1Ring[(i + 1) % priv->opts.rx_descs1];
@@ -838,7 +843,10 @@ static int device_rx_srv(struct vnt_private *priv, unsigned int idx)
 			dev_err(&priv->pcid->dev,
 				"can not allocate rx buf\n");
 			break;
+		} else {
+			device_init_rx_desc(priv, rd);
 		}
+
 		rd->rd0.owner = OWNED_BY_NIC;
 	}
 
@@ -865,15 +873,17 @@ static bool device_alloc_rx_buf(struct vnt_private *priv,
 		rd_info->skb = NULL;
 		return false;
 	}
+	return true;
+}
 
+static void device_init_rx_desc(struct vnt_private *priv, struct vnt_rx_desc *rd)
+{
 	*((unsigned int *)&rd->rd0) = 0; /* FIX cast */
 
 	rd->rd0.res_count = cpu_to_le16(priv->rx_buf_sz);
 	rd->rd0.owner = OWNED_BY_NIC;
 	rd->rd1.req_count = cpu_to_le16(priv->rx_buf_sz);
-	rd->buff_addr = cpu_to_le32(rd_info->skb_dma);
-
-	return true;
+	rd->buff_addr = cpu_to_le32(rd->rd_info->skb_dma);
 }
 
 static void device_free_rx_buf(struct vnt_private *priv,
-- 
2.25.1
Re: [RFC PATCH 3/5] staging: vt6655: split device_alloc_rx_buf
Posted by Dan Carpenter 3 years, 6 months ago 
On Thu, Sep 15, 2022 at 10:29:34PM +0200, Nam Cao wrote:
> The function device_alloc_rx_buf does 2 things: allocating rx buffer
> and initializing the rx descriptor's values. Split this function into
> two, with each does one job.
> 
> This split is preparation for implementing correct out-of-memory error
> handling.
> 
> Signed-off-by: Nam Cao <namcaov@gmail.com>
> ---
>  drivers/staging/vt6655/device_main.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
> index 79325a693857..27fe28156257 100644
> --- a/drivers/staging/vt6655/device_main.c
> +++ b/drivers/staging/vt6655/device_main.c
> @@ -133,6 +133,7 @@ static int device_init_td1_ring(struct vnt_private *priv);
>  static int  device_rx_srv(struct vnt_private *priv, unsigned int idx);
>  static int  device_tx_srv(struct vnt_private *priv, unsigned int idx);
>  static bool device_alloc_rx_buf(struct vnt_private *, struct vnt_rx_desc *);
> +static void device_init_rx_desc(struct vnt_private *priv, struct vnt_rx_desc *rd);
>  static void device_free_rx_buf(struct vnt_private *priv,
>  			       struct vnt_rx_desc *rd);
>  static void device_init_registers(struct vnt_private *priv);
> @@ -615,6 +616,8 @@ static int device_init_rd0_ring(struct vnt_private *priv)
>  			dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
>  			ret = -ENOMEM;
>  			goto err_free_rd;
> +		} else {
> +			device_init_rx_desc(priv, desc);
>  		}

None of these else statements make sense.  It should be:

		ret = -ENOMEM;
		goto err_free_rd;
	}

	device_init_rx_desc(priv, desc);
	desc->next = &priv->aRD0Ring[(i + 1) % priv->opts.rx_descs0];

I haven't reviewed the patch totally.  I don't understand why it's doing
this here instead of at the end.  But then I don't understand why it
needs to be in a separate function at all.

This patch does not make sense.  The commit description says that this
is a "preparation" patch.  Maybe fold it in with patch 5?  The rule is
"one thing per patch" not "half a thing per patch".

regards,
dan carpenter
Re: [RFC PATCH 3/5] staging: vt6655: split device_alloc_rx_buf
Posted by Nam Cao 3 years, 6 months ago 
On Mon, Sep 19, 2022 at 12:36:05PM +0300, Dan Carpenter wrote:
> On Thu, Sep 15, 2022 at 10:29:34PM +0200, Nam Cao wrote:
> > The function device_alloc_rx_buf does 2 things: allocating rx buffer
> > and initializing the rx descriptor's values. Split this function into
> > two, with each does one job.
> > 
> > This split is preparation for implementing correct out-of-memory error
> > handling.
> > 
> > Signed-off-by: Nam Cao <namcaov@gmail.com>
> > ---
> >  drivers/staging/vt6655/device_main.c | 16 +++++++++++++---
> >  1 file changed, 13 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
> > index 79325a693857..27fe28156257 100644
> > --- a/drivers/staging/vt6655/device_main.c
> > +++ b/drivers/staging/vt6655/device_main.c
> > @@ -133,6 +133,7 @@ static int device_init_td1_ring(struct vnt_private *priv);
> >  static int  device_rx_srv(struct vnt_private *priv, unsigned int idx);
> >  static int  device_tx_srv(struct vnt_private *priv, unsigned int idx);
> >  static bool device_alloc_rx_buf(struct vnt_private *, struct vnt_rx_desc *);
> > +static void device_init_rx_desc(struct vnt_private *priv, struct vnt_rx_desc *rd);
> >  static void device_free_rx_buf(struct vnt_private *priv,
> >  			       struct vnt_rx_desc *rd);
> >  static void device_init_registers(struct vnt_private *priv);
> > @@ -615,6 +616,8 @@ static int device_init_rd0_ring(struct vnt_private *priv)
> >  			dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
> >  			ret = -ENOMEM;
> >  			goto err_free_rd;
> > +		} else {
> > +			device_init_rx_desc(priv, desc);
> >  		}
> 
> None of these else statements make sense.  It should be:
> 
> 		ret = -ENOMEM;
> 		goto err_free_rd;
> 	}
> 
> 	device_init_rx_desc(priv, desc);
> 	desc->next = &priv->aRD0Ring[(i + 1) % priv->opts.rx_descs0];

That does look better, will be changed.

> I haven't reviewed the patch totally.  I don't understand why it's doing
> this here instead of at the end.  But then I don't understand why it
> needs to be in a separate function at all.
> 
> This patch does not make sense.  The commit description says that this
> is a "preparation" patch.  Maybe fold it in with patch 5?  The rule is
> "one thing per patch" not "half a thing per patch".

I thought splitting it like this would make it easier to review. But if
these preparation patches are not welcomed, I will squash them and
resend.

Thank you for spending time reviewing the patches.

Best regards,
Nam

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