re: net/hsr: Better frame dispatch

re: net/hsr: Better frame dispatch

[Dan Carpenter]

Hello Arvid Brodin,

The patch f266a683a480: "net/hsr: Better frame dispatch" from Jul 4,
2014, leads to the following static checker warning:

	net/hsr/hsr_framereg.c:293 hsr_addr_subst_dest()
	warn: this array is probably non-NULL. 'node_dst->MacAddressB'

net/hsr/hsr_framereg.c
   286          node_dst = find_node_by_AddrA(&port->hsr->node_db, eth_hdr(skb)->h_dest);
   287          if (!node_dst) {
   288                  WARN_ONCE(1, "%s: Unknown node\n", __func__);
   289                  return;
   290          }
   291          if (port->type != node_dst->AddrB_port)
   292                  return;
   293          if (!node_dst->MacAddressB) {
                    ^^^^^^^^^^^^^^^^^^^^^^
This test is never true.  It could be deleted or replaced.

   294                  WARN_ONCE(1, "%s: No MacAddressB\n", __func__);
   295                  return;
   296          }
   297  

regards,
dan carpenter

Re: net/hsr: Better frame dispatch

[Arvid Brodin]

On 2014-07-10 23:00, Dan Carpenter wrote:
> Hello Arvid Brodin,
> 
> The patch f266a683a480: "net/hsr: Better frame dispatch" from Jul 4,
> 2014, leads to the following static checker warning:
> 
> 	net/hsr/hsr_framereg.c:293 hsr_addr_subst_dest()
> 	warn: this array is probably non-NULL. 'node_dst->MacAddressB'
> 
> net/hsr/hsr_framereg.c
>    286          node_dst = find_node_by_AddrA(&port->hsr->node_db, eth_hdr(skb)->h_dest);
>    287          if (!node_dst) {
>    288                  WARN_ONCE(1, "%s: Unknown node\n", __func__);
>    289                  return;
>    290          }
>    291          if (port->type != node_dst->AddrB_port)
>    292                  return;
>    293          if (!node_dst->MacAddressB) {
>                     ^^^^^^^^^^^^^^^^^^^^^^
> This test is never true.  It could be deleted or replaced.
> 
>    294                  WARN_ONCE(1, "%s: No MacAddressB\n", __func__);
>    295                  return;
>    296          }
>    297  
> 

Yes, this code (the whole if block; lines 293-296) is useless and should be deleted. 
Thanks for finding it!


-- 
Arvid Brodin | Consultant (Linux)
ALTEN | Knarrarnäsgatan 7 | SE-164 40 Kista | Sweden
arvid.brodin@alten.se | www.alten.se/en/

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[PATCH net-next] net/hsr: Remove left-over never-true conditional code.

[Arvid Brodin]

MacAddressB is an array (unsigned char MacAddressB[ETH_ALEN]) and is allocated
as a part of *node_dst (which is a struct hsr_node). So the condition is always
false.

Detected by Dan Carpenter.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
---
 net/hsr/hsr_framereg.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
index c709c13..bace124 100644
--- a/net/hsr/hsr_framereg.c
+++ b/net/hsr/hsr_framereg.c
@@ -290,10 +290,6 @@ void hsr_addr_subst_dest(struct hsr_node *node_src, struct sk_buff *skb,
 	}
 	if (port->type != node_dst->AddrB_port)
 		return;
-	if (!node_dst->MacAddressB) {
-		WARN_ONCE(1, "%s: No MacAddressB\n", __func__);
-		return;
-	}
 
 	ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->MacAddressB);
 }
-- 
1.8.3.2

-- 
Arvid Brodin | Consultant (Linux)
ALTEN | Knarrarnäsgatan 7 | SE-164 40 Kista | Sweden
arvid.brodin@alten.se | www.alten.se/en/
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Re: [PATCH net-next] net/hsr: Remove left-over never-true conditional code.

[David Miller]

From: Arvid Brodin <arvid.brodin@alten.se>
Date: Fri, 11 Jul 2014 18:21:12 +0200

> MacAddressB is an array (unsigned char MacAddressB[ETH_ALEN]) and is allocated
> as a part of *node_dst (which is a struct hsr_node). So the condition is always
> false.
> 
> Detected by Dan Carpenter.
> 
> Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>

Applied, thanks.