* [PATCH] skb: add a comment to skb_csum_unnecessary to avoid miuse
@ 2013-01-23 0:30 Koki Sanagi
2013-01-23 1:53 ` David Miller
0 siblings, 1 reply; 6+ messages in thread
From: Koki Sanagi @ 2013-01-23 0:30 UTC (permalink / raw)
To: netdev; +Cc: davem
Due to its name and appearance, someone thinks this only checks if ip_summed is
CHECKSUM_UNNECESARRY. But actually, this returns true even if ip_summed is
CHECKSUM_PARTIAL. To avoid misuse, this patch a comment which specifies that
CHECKSUM_PARTIAL is OK.
Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
---
include/linux/skbuff.h | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 8b2256e..bc41f64 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2522,6 +2522,16 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
+/**
+ * skb_csum_unnecessary - check if the checksum needs to be verified
+ * @skb: skb to check
+ *
+ * check if the checksum of this skb needs to be verified. This function is
+ * effective only against skbs on inbound path.
+ *
+ * NB: This returns true if ip_summed is CHECKSUM_UNNECESSARY or
+ * CHECKSUM_PARTIAL.
+ **/
static inline int skb_csum_unnecessary(const struct sk_buff *skb)
{
return skb->ip_summed & CHECKSUM_UNNECESSARY;
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] skb: add a comment to skb_csum_unnecessary to avoid miuse
2013-01-23 0:30 [PATCH] skb: add a comment to skb_csum_unnecessary to avoid miuse Koki Sanagi
@ 2013-01-23 1:53 ` David Miller
2013-01-23 2:32 ` Sanagi, Koki
0 siblings, 1 reply; 6+ messages in thread
From: David Miller @ 2013-01-23 1:53 UTC (permalink / raw)
To: sanagi.koki; +Cc: netdev
From: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
Date: Wed, 23 Jan 2013 09:30:16 +0900
> Due to its name and appearance, someone thinks this only checks if ip_summed is
> CHECKSUM_UNNECESARRY. But actually, this returns true even if ip_summed is
> CHECKSUM_PARTIAL. To avoid misuse, this patch a comment which specifies that
> CHECKSUM_PARTIAL is OK.
>
> Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
I'm not applying this, sorry. It's a one line function and it's not
so non-obvious that it deserves an 8 line comment.
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH] skb: add a comment to skb_csum_unnecessary to avoid miuse
2013-01-23 1:53 ` David Miller
@ 2013-01-23 2:32 ` Sanagi, Koki
2013-01-23 4:13 ` David Miller
0 siblings, 1 reply; 6+ messages in thread
From: Sanagi, Koki @ 2013-01-23 2:32 UTC (permalink / raw)
To: David Miller; +Cc: netdev@vger.kernel.org
> From: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
> Date: Wed, 23 Jan 2013 09:30:16 +0900
>
> > Due to its name and appearance, someone thinks this only checks if
> > ip_summed is CHECKSUM_UNNECESARRY. But actually, this returns true
> > even if ip_summed is CHECKSUM_PARTIAL. To avoid misuse, this patch a
> > comment which specifies that CHECKSUM_PARTIAL is OK.
> >
> > Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
>
> I'm not applying this, sorry. It's a one line function and it's not so
> non-obvious that it deserves an 8 line comment.
OK. I just felt weird that CHECKSUM_* is not bit flag but this function handles
it as if it was bit flag.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] skb: add a comment to skb_csum_unnecessary to avoid miuse
2013-01-23 2:32 ` Sanagi, Koki
@ 2013-01-23 4:13 ` David Miller
2013-01-23 5:11 ` Sanagi, Koki
0 siblings, 1 reply; 6+ messages in thread
From: David Miller @ 2013-01-23 4:13 UTC (permalink / raw)
To: sanagi.koki; +Cc: netdev
From: "Sanagi, Koki" <sanagi.koki@jp.fujitsu.com>
Date: Wed, 23 Jan 2013 02:32:52 +0000
>> From: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
>> Date: Wed, 23 Jan 2013 09:30:16 +0900
>>
>> > Due to its name and appearance, someone thinks this only checks if
>> > ip_summed is CHECKSUM_UNNECESARRY. But actually, this returns true
>> > even if ip_summed is CHECKSUM_PARTIAL. To avoid misuse, this patch a
>> > comment which specifies that CHECKSUM_PARTIAL is OK.
>> >
>> > Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
>>
>> I'm not applying this, sorry. It's a one line function and it's not so
>> non-obvious that it deserves an 8 line comment.
>
> OK. I just felt weird that CHECKSUM_* is not bit flag but this function handles
> it as if it was bit flag.
The function name says what it does, it determines whether a checksum
is necessary or not. How that is implemented is another issue.
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH] skb: add a comment to skb_csum_unnecessary to avoid miuse
2013-01-23 4:13 ` David Miller
@ 2013-01-23 5:11 ` Sanagi, Koki
2013-01-23 5:21 ` David Miller
0 siblings, 1 reply; 6+ messages in thread
From: Sanagi, Koki @ 2013-01-23 5:11 UTC (permalink / raw)
To: David Miller; +Cc: netdev@vger.kernel.org
> From: "Sanagi, Koki" <sanagi.koki@jp.fujitsu.com>
> Date: Wed, 23 Jan 2013 02:32:52 +0000
>
> >> From: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
> >> Date: Wed, 23 Jan 2013 09:30:16 +0900
> >>
> >> > Due to its name and appearance, someone thinks this only checks if
> >> > ip_summed is CHECKSUM_UNNECESARRY. But actually, this returns true
> >> > even if ip_summed is CHECKSUM_PARTIAL. To avoid misuse, this patch
> >> > a comment which specifies that CHECKSUM_PARTIAL is OK.
> >> >
> >> > Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
> >>
> >> I'm not applying this, sorry. It's a one line function and it's not
> >> so non-obvious that it deserves an 8 line comment.
> >
> > OK. I just felt weird that CHECKSUM_* is not bit flag but this
> > function handles it as if it was bit flag.
>
> The function name says what it does, it determines whether a checksum is
> necessary or not. How that is implemented is another issue.
As for name of the function which confused me, I'm ok now. But as for how to implement,
I still think it is inappropriate because of the above reason. So, how about introducing
CHECKSUM_UNNECESSARY_BIT like below ?
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 8b2256e..b1dbd36 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -39,6 +39,8 @@
#define CHECKSUM_COMPLETE 2
#define CHECKSUM_PARTIAL 3
+#define CHECKSUM_UNNECESSARY_BIT (1 << 0)
+
#define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
~(SMP_CACHE_BYTES - 1))
#define SKB_WITH_OVERHEAD(X) \
@@ -2524,7 +2526,7 @@ extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
static inline int skb_csum_unnecessary(const struct sk_buff *skb)
{
- return skb->ip_summed & CHECKSUM_UNNECESSARY;
+ return skb->ip_summed & CHECKSUM_UNNECESSARY_BIT;
}
/**
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] skb: add a comment to skb_csum_unnecessary to avoid miuse
2013-01-23 5:11 ` Sanagi, Koki
@ 2013-01-23 5:21 ` David Miller
0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2013-01-23 5:21 UTC (permalink / raw)
To: sanagi.koki; +Cc: netdev
From: "Sanagi, Koki" <sanagi.koki@jp.fujitsu.com>
Date: Wed, 23 Jan 2013 05:11:14 +0000
> As for name of the function which confused me, I'm ok now. But as
> for how to implement, I still think it is inappropriate because of
> the above reason. So, how about introducing
> CHECKSUM_UNNECESSARY_BIT like below ?
If the user has to look at the implementation, they will see
the "&" and there is no confusion.
Please stop splitting hairs, this is a waste of time.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-01-23 5:21 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-01-23 0:30 [PATCH] skb: add a comment to skb_csum_unnecessary to avoid miuse Koki Sanagi
2013-01-23 1:53 ` David Miller
2013-01-23 2:32 ` Sanagi, Koki
2013-01-23 4:13 ` David Miller
2013-01-23 5:11 ` Sanagi, Koki
2013-01-23 5:21 ` David Miller
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).