[PATCH] pcnet32.c: modify RX ring size through module parameter

[PATCH] pcnet32.c: modify RX ring size through module parameter

[Wen Hsin Chang]

This patch is created from pcnet32.c v1.32. it will allow users to 
specify RX ring size upon module
insertion via module parameter 'rx_log_size'. This is needed in some 
cases where too small the rx ring
size will cause RX errors upon remote installation via pcnet32 NIC card.

Signed-off-by: Wen Hsin Chang <whchang@tw.ibm.com>
----------------------------------------------------------------------------------------------------

--- a/drivers/net/pcnet32.c    2006-03-30 09:49:10.000000000 +0800
+++ b/drivers/net/pcnet32.c    2006-05-15 11:14:45.000000000 +0800
@@ -93,6 +93,9 @@ static struct net_device *pcnet32_dev;
 static int max_interrupt_work = 2;
 static int rx_copybreak = 200;
 
+/* Module parameter to specify RX ring size at module insertion */
+static int rx_log_size = 0;
+
 #define PCNET32_PORT_AUI      0x00
 #define PCNET32_PORT_10BT     0x01
 #define PCNET32_PORT_GPSI     0x02
@@ -1264,7 +1267,10 @@ pcnet32_probe1(unsigned long ioaddr, int
     lp->name = chipname;
     lp->shared_irq = shared;
     lp->tx_ring_size = TX_RING_SIZE;    /* default tx ring size */
-    lp->rx_ring_size = RX_RING_SIZE;    /* default rx ring size */
+    if (!rx_log_size)
+        lp->rx_ring_size = RX_RING_SIZE;    /* default rx ring size */
+    else
+        lp->rx_ring_size = (1 << (rx_log_size));
     lp->tx_mod_mask = lp->tx_ring_size - 1;
     lp->rx_mod_mask = lp->rx_ring_size - 1;
     lp->tx_len_bits = (PCNET32_LOG_TX_BUFFERS << 12);
@@ -2707,6 +2713,11 @@ module_param(tx_start_pt, int, 0);
 MODULE_PARM_DESC(tx_start_pt, DRV_NAME " transmit start point (0-3)");
 module_param(pcnet32vlb, int, 0);
 MODULE_PARM_DESC(pcnet32vlb, DRV_NAME " Vesa local bus (VLB) support 
(0/1)");
+
+/* Module parameter to specify RX ring size at module insertion */
+module_param(rx_log_size, int, 0);
+MODULE_PARM_DESC(rx_log_size, DRV_NAME " RX Ring Buffer Size (log_2 
#BUF) ");
+
 module_param_array(options, int, NULL, 0);
 MODULE_PARM_DESC(options, DRV_NAME " initial option setting(s) (0-15)");
 module_param_array(full_duplex, int, NULL, 0);
@@ -2731,6 +2742,12 @@ static int __init pcnet32_init_module(vo
 
     if ((tx_start_pt >= 0) && (tx_start_pt <= 3))
         tx_start = tx_start_pt;
+       
+    /* validating rx_log_size */
+    if ((rx_log_size <= 0) ||
+        (rx_log_size > PCNET32_LOG_MAX_RX_BUFFERS))
+        rx_log_size = 0;
+       
 
     /* find the PCI devices */
     if (!pci_module_init(&pcnet32_driver))

Re: [PATCH] pcnet32.c: modify RX ring size through module parameter

[Don Fry]

I have several problems with this patch.  First, it assumes you only have
one device or you want all devices to operate with the same receive ring
size.  (use module_param_array like full_duplex or options).

Second, the mininum number of descriptors should be 4 not 2, or the
loopback test will look past the end of the receive ring looking for
status to change, and then try and pick up an skb pointer past the end of
the array and try to dereference it.

Either fix the loopback test to work with the minimum number of tx and rx
descriptors instead of the hard coded 4, or make the minimum rx ring
size be 4.  numbuffs = min(4 , min(lp->tx_ring_size, lp->rx_ring_size));

Another nit is the description says it is the "RX Ring Buffer Size" which
might be misunderstood as the size of the receive buffer, not the size of
the receive descriptor ring.  ("RX Ring Size" would be better).

Lastly, the patch also will not apply against pcnet32.c in mainline
2.6.17-rc4 due to whitespace changes.

On Mon, May 15, 2006 at 11:32:14AM +0800, Wen Hsin Chang wrote:
> This patch is created from pcnet32.c v1.32. it will allow users to 
> specify RX ring size upon module
> insertion via module parameter 'rx_log_size'. This is needed in some 
> cases where too small the rx ring
> size will cause RX errors upon remote installation via pcnet32 NIC card.
> 
> Signed-off-by: Wen Hsin Chang <whchang@tw.ibm.com>

-- 
Don Fry
brazilnut@us.ibm.com

Re: [PATCH] pcnet32.c: modify RX ring size through module parameter

[Jon Mason]

Why is this necessary?  There is already an ethtool function to set
the rx ring size (pcnet32_set_ringparam).  Since module parameters
are being phased out in favor of the ethtool functions, why not use
the existing ethtool infrastructure for this?

Thanks,
Jon

On Mon, May 15, 2006 at 11:32:14AM +0800, Wen Hsin Chang wrote:
> This patch is created from pcnet32.c v1.32. it will allow users to 
> specify RX ring size upon module
> insertion via module parameter 'rx_log_size'. This is needed in some 
> cases where too small the rx ring
> size will cause RX errors upon remote installation via pcnet32 NIC card.
> 
> Signed-off-by: Wen Hsin Chang <whchang@tw.ibm.com>
> ----------------------------------------------------------------------------------------------------
> 
> --- a/drivers/net/pcnet32.c    2006-03-30 09:49:10.000000000 +0800
> +++ b/drivers/net/pcnet32.c    2006-05-15 11:14:45.000000000 +0800
> @@ -93,6 +93,9 @@ static struct net_device *pcnet32_dev;
> static int max_interrupt_work = 2;
> static int rx_copybreak = 200;
> 
> +/* Module parameter to specify RX ring size at module insertion */
> +static int rx_log_size = 0;
> +
> #define PCNET32_PORT_AUI      0x00
> #define PCNET32_PORT_10BT     0x01
> #define PCNET32_PORT_GPSI     0x02
> @@ -1264,7 +1267,10 @@ pcnet32_probe1(unsigned long ioaddr, int
>     lp->name = chipname;
>     lp->shared_irq = shared;
>     lp->tx_ring_size = TX_RING_SIZE;    /* default tx ring size */
> -    lp->rx_ring_size = RX_RING_SIZE;    /* default rx ring size */
> +    if (!rx_log_size)
> +        lp->rx_ring_size = RX_RING_SIZE;    /* default rx ring size */
> +    else
> +        lp->rx_ring_size = (1 << (rx_log_size));
>     lp->tx_mod_mask = lp->tx_ring_size - 1;
>     lp->rx_mod_mask = lp->rx_ring_size - 1;
>     lp->tx_len_bits = (PCNET32_LOG_TX_BUFFERS << 12);
> @@ -2707,6 +2713,11 @@ module_param(tx_start_pt, int, 0);
> MODULE_PARM_DESC(tx_start_pt, DRV_NAME " transmit start point (0-3)");
> module_param(pcnet32vlb, int, 0);
> MODULE_PARM_DESC(pcnet32vlb, DRV_NAME " Vesa local bus (VLB) support 
> (0/1)");
> +
> +/* Module parameter to specify RX ring size at module insertion */
> +module_param(rx_log_size, int, 0);
> +MODULE_PARM_DESC(rx_log_size, DRV_NAME " RX Ring Buffer Size (log_2 
> #BUF) ");
> +
> module_param_array(options, int, NULL, 0);
> MODULE_PARM_DESC(options, DRV_NAME " initial option setting(s) (0-15)");
> module_param_array(full_duplex, int, NULL, 0);
> @@ -2731,6 +2742,12 @@ static int __init pcnet32_init_module(vo
> 
>     if ((tx_start_pt >= 0) && (tx_start_pt <= 3))
>         tx_start = tx_start_pt;
> +       
> +    /* validating rx_log_size */
> +    if ((rx_log_size <= 0) ||
> +        (rx_log_size > PCNET32_LOG_MAX_RX_BUFFERS))
> +        rx_log_size = 0;
> +       
> 
>     /* find the PCI devices */
>     if (!pci_module_init(&pcnet32_driver))
> 
> -
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
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Re: [PATCH] pcnet32.c: modify RX ring size through module parameter

[Wen Hsin Chang]

There are cases where rx errors were found due to rx ring size being too 
small
during remote installation using pcnet32. It is found that ethtool 
functionality
may not be available under such circumenstance. This is the purpose behind
this patch.

However, as Don pointed out, there are several points that need to be
considered. I'll further revise this patch and see how to come up with
a better solution.

Thanks for your comment~

Wen Hsin Chang

Jon Mason wrote:

>Why is this necessary?  There is already an ethtool function to set
>the rx ring size (pcnet32_set_ringparam).  Since module parameters
>are being phased out in favor of the ethtool functions, why not use
>the existing ethtool infrastructure for this?
>
>Thanks,
>Jon
>
>On Mon, May 15, 2006 at 11:32:14AM +0800, Wen Hsin Chang wrote:
>  
>
>>This patch is created from pcnet32.c v1.32. it will allow users to 
>>specify RX ring size upon module
>>insertion via module parameter 'rx_log_size'. This is needed in some 
>>cases where too small the rx ring
>>size will cause RX errors upon remote installation via pcnet32 NIC card.
>>
>>Signed-off-by: Wen Hsin Chang <whchang@tw.ibm.com>
>>----------------------------------------------------------------------------------------------------
>>
>>--- a/drivers/net/pcnet32.c    2006-03-30 09:49:10.000000000 +0800
>>+++ b/drivers/net/pcnet32.c    2006-05-15 11:14:45.000000000 +0800
>>@@ -93,6 +93,9 @@ static struct net_device *pcnet32_dev;
>>static int max_interrupt_work = 2;
>>static int rx_copybreak = 200;
>>
>>+/* Module parameter to specify RX ring size at module insertion */
>>+static int rx_log_size = 0;
>>+
>>#define PCNET32_PORT_AUI      0x00
>>#define PCNET32_PORT_10BT     0x01
>>#define PCNET32_PORT_GPSI     0x02
>>@@ -1264,7 +1267,10 @@ pcnet32_probe1(unsigned long ioaddr, int
>>    lp->name = chipname;
>>    lp->shared_irq = shared;
>>    lp->tx_ring_size = TX_RING_SIZE;    /* default tx ring size */
>>-    lp->rx_ring_size = RX_RING_SIZE;    /* default rx ring size */
>>+    if (!rx_log_size)
>>+        lp->rx_ring_size = RX_RING_SIZE;    /* default rx ring size */
>>+    else
>>+        lp->rx_ring_size = (1 << (rx_log_size));
>>    lp->tx_mod_mask = lp->tx_ring_size - 1;
>>    lp->rx_mod_mask = lp->rx_ring_size - 1;
>>    lp->tx_len_bits = (PCNET32_LOG_TX_BUFFERS << 12);
>>@@ -2707,6 +2713,11 @@ module_param(tx_start_pt, int, 0);
>>MODULE_PARM_DESC(tx_start_pt, DRV_NAME " transmit start point (0-3)");
>>module_param(pcnet32vlb, int, 0);
>>MODULE_PARM_DESC(pcnet32vlb, DRV_NAME " Vesa local bus (VLB) support 
>>(0/1)");
>>+
>>+/* Module parameter to specify RX ring size at module insertion */
>>+module_param(rx_log_size, int, 0);
>>+MODULE_PARM_DESC(rx_log_size, DRV_NAME " RX Ring Buffer Size (log_2 
>>#BUF) ");
>>+
>>module_param_array(options, int, NULL, 0);
>>MODULE_PARM_DESC(options, DRV_NAME " initial option setting(s) (0-15)");
>>module_param_array(full_duplex, int, NULL, 0);
>>@@ -2731,6 +2742,12 @@ static int __init pcnet32_init_module(vo
>>
>>    if ((tx_start_pt >= 0) && (tx_start_pt <= 3))
>>        tx_start = tx_start_pt;
>>+       
>>+    /* validating rx_log_size */
>>+    if ((rx_log_size <= 0) ||
>>+        (rx_log_size > PCNET32_LOG_MAX_RX_BUFFERS))
>>+        rx_log_size = 0;
>>+       
>>
>>    /* find the PCI devices */
>>    if (!pci_module_init(&pcnet32_driver))
>>
>>-
>>To unsubscribe from this list: send the line "unsubscribe netdev" in
>>the body of a message to majordomo@vger.kernel.org
>>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>    
>>
>-
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>
>  
>