handling MAC set by user space in reset_resume() of r8152

Commit Message

Oliver Neukum July 27, 2022, 11:39 a.m. UTC

Hi,

looking at the driver it looks to me like the address
provided to ndo_set_mac_address() is thrown away after use.
That looks problematic to me, because reset_resume()
should redo the operation.
What do you think?

	Regards
		Oliver

Comments

Andrew Lunn July 27, 2022, 6:34 p.m. UTC | #1

On Wed, Jul 27, 2022 at 01:39:43PM +0200, Oliver Neukum wrote:
> Hi,
> 
> looking at the driver it looks to me like the address
> provided to ndo_set_mac_address() is thrown away after use.
> That looks problematic to me, because reset_resume()
> should redo the operation.
> What do you think?
> 
> 	Regards
> 		Oliver

> From 19fc972a5cc98197bc81a7c56dd5d68e3fdfc36b Mon Sep 17 00:00:00 2001
> From: Oliver Neukum <[e-mail]>
> Date: Wed, 27 Jul 2022 13:29:42 +0200
> Subject: [PATCH] r8152: restore external MAC in reset_resume
> 
> If user space has set the MAC of the interface,
> reset_resume() must restore that setting rather
> than redetermine the MAC like if te interface
> is probed regularly.
> 
> Signed-off-by: Oliver Neukum <[e-mail]>
> ---
>  drivers/net/usb/r8152.c | 34 +++++++++++++++++++++++++---------
>  1 file changed, 25 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index 0f6efaabaa32..5cf74b984655 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -923,6 +923,7 @@ struct r8152 {
>  	atomic_t rx_count;
>  
>  	bool eee_en;
> +	bool external_mac;
>  	int intr_interval;
>  	u32 saved_wolopts;
>  	u32 msg_enable;
> @@ -933,6 +934,8 @@ struct r8152 {
>  	u32 rx_copybreak;
>  	u32 rx_pending;
>  	u32 fc_pause_on, fc_pause_off;
> +	/* for reset_resume */
> +	struct sockaddr saved_addr;
>  
>  	unsigned int pipe_in, pipe_out, pipe_intr, pipe_ctrl_in, pipe_ctrl_out;
>  
> @@ -1574,6 +1577,7 @@ static int __rtl8152_set_mac_address(struct net_device *netdev, void *p,
>  	mutex_lock(&tp->control);
>  
>  	eth_hw_addr_set(netdev, addr->sa_data);
> +	memcpy(&tp->saved_addr, addr, sizeof(tp->saved_addr));

Do you need a copy in tp? I would expect the MAC address stored in
netdev by eth_hw_addr_set() is still there after the resume?

       Andrew

Hayes Wang July 28, 2022, 8:40 a.m. UTC | #2

Oliver Neukum <[e-mail]>
> > Date: Wed, 27 Jul 2022 13:29:42 +0200
> > Subject: [PATCH] r8152: restore external MAC in reset_resume
> >
> > If user space has set the MAC of the interface,
> > reset_resume() must restore that setting rather
> > than redetermine the MAC like if te interface
> > is probed regularly.

I think this patch conflicts with commit 25766271e42f ("r8152: Refresh
MAC address during USBDEVFS_RESET"). The results would be changed.

Besides, I don't understand why you set tp->external_mac = false
in rtl8152_down().

Best Regards,
Hayes

Oliver Neukum July 28, 2022, 8:54 a.m. UTC | #3

On 28.07.22 10:40, Hayes Wang wrote:
> Oliver Neukum <[e-mail]>
>>> Date: Wed, 27 Jul 2022 13:29:42 +0200
>>> Subject: [PATCH] r8152: restore external MAC in reset_resume
>>>
>>> If user space has set the MAC of the interface,
>>> reset_resume() must restore that setting rather
>>> than redetermine the MAC like if te interface
>>> is probed regularly.
> 
> I think this patch conflicts with commit 25766271e42f ("r8152: Refresh
> MAC address during USBDEVFS_RESET"). The results would be changed.

Argh.
OK, thank you. Do you agree that a manually set MAC needs to be kept
even through a pre/post_reset() and reset_resume(), while a MAC passed
through needs to be reevaluated at pre/post_reset() but not at
reset_resume()

> Besides, I don't understand why you set tp->external_mac = false
> in rtl8152_down().

Frankly I need to undo the effect of ndo_set_mac_address()
at some time, but it is unclear to me how to return a network
interface to its "native" MAC.
Any ideas?

	Regards
		Oliver

Hayes Wang July 28, 2022, 9:41 a.m. UTC | #4

Oliver Neukum <[e-mail]>
[...]
> OK, thank you. Do you agree that a manually set MAC needs to be kept
> even through a pre/post_reset() and reset_resume(), while a MAC passed
> through needs to be reevaluated at pre/post_reset() but not at
> reset_resume()

Yes. I think a user wishes to keep it.

> > Besides, I don't understand why you set tp->external_mac = false
> > in rtl8152_down().
> 
> Frankly I need to undo the effect of ndo_set_mac_address()
> at some time, but it is unclear to me how to return a network
> interface to its "native" MAC.
> Any ideas?

I am not sure. Is it necessary?
If I change the MAC address, I don't hope it is recovered unexpectedly
unless the system is rebooted or shutdown.

Best Regards,
Hayes

Patch

From 19fc972a5cc98197bc81a7c56dd5d68e3fdfc36b Mon Sep 17 00:00:00 2001
From: Oliver Neukum <[e-mail]>
Date: Wed, 27 Jul 2022 13:29:42 +0200
Subject: [PATCH] r8152: restore external MAC in reset_resume

If user space has set the MAC of the interface,
reset_resume() must restore that setting rather
than redetermine the MAC like if te interface
is probed regularly.

Signed-off-by: Oliver Neukum <[e-mail]>
---
 drivers/net/usb/r8152.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 0f6efaabaa32..5cf74b984655 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -923,6 +923,7 @@  struct r8152 {
 	atomic_t rx_count;
 
 	bool eee_en;
+	bool external_mac;
 	int intr_interval;
 	u32 saved_wolopts;
 	u32 msg_enable;
@@ -933,6 +934,8 @@  struct r8152 {
 	u32 rx_copybreak;
 	u32 rx_pending;
 	u32 fc_pause_on, fc_pause_off;
+	/* for reset_resume */
+	struct sockaddr saved_addr;
 
 	unsigned int pipe_in, pipe_out, pipe_intr, pipe_ctrl_in, pipe_ctrl_out;
 
@@ -1574,6 +1577,7 @@  static int __rtl8152_set_mac_address(struct net_device *netdev, void *p,
 	mutex_lock(&tp->control);
 
 	eth_hw_addr_set(netdev, addr->sa_data);
+	memcpy(&tp->saved_addr, addr, sizeof(tp->saved_addr));
 
 	ocp_write_byte(tp, MCU_TYPE_PLA, PLA_CRWECR, CRWECR_CONFIG);
 	pla_ocp_write(tp, PLA_IDR, BYTE_EN_SIX_BYTES, 8, addr->sa_data);
@@ -1589,7 +1593,13 @@  static int __rtl8152_set_mac_address(struct net_device *netdev, void *p,
 
 static int rtl8152_set_mac_address(struct net_device *netdev, void *p)
 {
-	return __rtl8152_set_mac_address(netdev, p, false);
+	int rv;
+	struct r8152 *tp = netdev_priv(netdev);
+
+	rv =  __rtl8152_set_mac_address(netdev, p, false);
+	if (!rv)
+		tp->external_mac = true;
+	return rv;
 }
 
 /* Devices containing proper chips can support a persistent
@@ -1676,10 +1686,14 @@  static int vendor_mac_passthru_addr_read(struct r8152 *tp, struct sockaddr *sa)
 static int determine_ethernet_addr(struct r8152 *tp, struct sockaddr *sa)
 {
 	struct net_device *dev = tp->netdev;
-	int ret;
+	int ret = 0;
 
 	sa->sa_family = dev->type;
 
+	if (tp->external_mac) {
+		ether_addr_copy(sa->sa_data, dev->dev_addr);
+		return ret;
+	}
 	ret = eth_platform_get_mac_address(&tp->udev->dev, sa->sa_data);
 	if (ret < 0) {
 		if (tp->version == RTL_VER_01) {
@@ -1713,17 +1727,18 @@  static int determine_ethernet_addr(struct r8152 *tp, struct sockaddr *sa)
 static int set_ethernet_addr(struct r8152 *tp, bool in_resume)
 {
 	struct net_device *dev = tp->netdev;
-	struct sockaddr sa;
-	int ret;
+	int ret = 0;
 
-	ret = determine_ethernet_addr(tp, &sa);
-	if (ret < 0)
-		return ret;
+	if (!tp->external_mac) {
+		ret = determine_ethernet_addr(tp, &tp->saved_addr);
+		if (ret < 0)
+			return ret;
+	}
 
 	if (tp->version == RTL_VER_01)
-		eth_hw_addr_set(dev, sa.sa_data);
+		eth_hw_addr_set(dev, tp->saved_addr.sa_data);
 	else
-		ret = __rtl8152_set_mac_address(dev, &sa, in_resume);
+		ret = __rtl8152_set_mac_address(dev, &tp->saved_addr, in_resume);
 
 	return ret;
 }
@@ -6225,6 +6240,7 @@  static void rtl8152_down(struct r8152 *tp)
 	r8152_aldps_en(tp, false);
 	r8152b_enter_oob(tp);
 	r8152_aldps_en(tp, true);
+	tp->external_mac = false;
 }
 
 static void rtl8153_up(struct r8152 *tp)
-- 
2.35.3