[PATCH net-next] net/core: Remove comment quote for __dev_queue_xmit()

[PATCH net-next] net/core: Remove comment quote for __dev_queue_xmit()

[Bagas Sanjaya]

When merging net-next for linux-next tree, Stephen Rothwell reported
htmldocs warning:

Documentation/networking/kapi:92: net/core/dev.c:4101: WARNING: Missing matching underline for section title overline.

-----------------------------------------------------------------------------------
     I notice this method can also return errors from the queue disciplines,
     including NET_XMIT_DROP, which is a positive value.  So, errors can also

The warning is due to comment quote by BLG, which is separated by a dash
line above. While it is fine in the docbook days, current documentation
framework (Sphinx + kernel-doc) complains about it, so the documentation
for __dev_queue_xmit() is not generated.

The commit containing the quote is actually d29f749e252bcd ("net: Fix
build failure with 'make mandocs'."), which interacts with commit
c526fd8f9f4f21 ("net: inline dev_queue_xmit()") that Stephen reported.

Fix the warning by removing the quote and adjust the method
documentation accordingly.

Fixes: d29f749e252bcd ("net: Fix build failure with 'make mandocs'.")
Link: https://lore.kernel.org/linux-next/20220503073420.6d3f135d@canb.auug.org.au/
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dave Jones <davej@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
---
 net/core/dev.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index d127164771f222..b5273f820ca840 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4098,18 +4098,13 @@ struct netdev_queue *netdev_core_pick_tx(struct net_device *dev,
  *	guarantee the frame will be transmitted as it may be dropped due
  *	to congestion or traffic shaping.
  *
- * -----------------------------------------------------------------------------------
- *      I notice this method can also return errors from the queue disciplines,
- *      including NET_XMIT_DROP, which is a positive value.  So, errors can also
- *      be positive.
- *
- *      Regardless of the return value, the skb is consumed, so it is currently
- *      difficult to retry a send to this method.  (You can bump the ref count
- *      before sending to hold a reference for retry if you are careful.)
- *
- *      When calling this method, interrupts MUST be enabled.  This is because
- *      the BH enable code must have IRQs enabled so that it will not deadlock.
- *          --BLG
+ *	This method can also return positive errno code from the queue
+ *	disciplines (including NET_XMIT_DROP).
+ *
+ *	Note that regardless of the return value, the skb is consumed
+ *	anyway, so it is currently difficult to retry sending to this
+ *	method.
+ *
  */
 int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
 {

base-commit: 0530a683fc858aa641d88ad83315ea53c27bce10
-- 
An old man doll... just what I always wanted! - Clara

Re: [PATCH net-next] net/core: Remove comment quote for __dev_queue_xmit()

[Jakub Kicinski]

On Tue,  3 May 2022 14:29:49 +0700 Bagas Sanjaya wrote:
> - * -----------------------------------------------------------------------------------
> - *      I notice this method can also return errors from the queue disciplines,
> - *      including NET_XMIT_DROP, which is a positive value.  So, errors can also
> - *      be positive.
> - *
> - *      Regardless of the return value, the skb is consumed, so it is currently
> - *      difficult to retry a send to this method.  (You can bump the ref count
> - *      before sending to hold a reference for retry if you are careful.)
> - *
> - *      When calling this method, interrupts MUST be enabled.  This is because
> - *      the BH enable code must have IRQs enabled so that it will not deadlock.
> - *          --BLG
> + *	This method can also return positive errno code from the queue
> + *	disciplines (including NET_XMIT_DROP).
> + *
> + *	Note that regardless of the return value, the skb is consumed
> + *	anyway, so it is currently difficult to retry sending to this
> + *	method.

Why drop almost half of the comment if the problem is just the ----
banner?

Re: [PATCH net-next] net/core: Remove comment quote for __dev_queue_xmit()

[Bagas Sanjaya]

On 5/4/22 08:03, Jakub Kicinski wrote:
> On Tue,  3 May 2022 14:29:49 +0700 Bagas Sanjaya wrote:
>> - * -----------------------------------------------------------------------------------
>> - *      I notice this method can also return errors from the queue disciplines,
>> - *      including NET_XMIT_DROP, which is a positive value.  So, errors can also
>> - *      be positive.
>> - *
>> - *      Regardless of the return value, the skb is consumed, so it is currently
>> - *      difficult to retry a send to this method.  (You can bump the ref count
>> - *      before sending to hold a reference for retry if you are careful.)
>> - *
>> - *      When calling this method, interrupts MUST be enabled.  This is because
>> - *      the BH enable code must have IRQs enabled so that it will not deadlock.
>> - *          --BLG
>> + *	This method can also return positive errno code from the queue
>> + *	disciplines (including NET_XMIT_DROP).
>> + *
>> + *	Note that regardless of the return value, the skb is consumed
>> + *	anyway, so it is currently difficult to retry sending to this
>> + *	method.
> 
> Why drop almost half of the comment if the problem is just the ----
> banner?

I can't think of preserving delineation between actual documentation
and the quote without messing up kernel-doc.

Actually the "--BLG" signature is the culprit.

-- 
An old man doll... just what I always wanted! - Clara

Re: [PATCH net-next] net/core: Remove comment quote for __dev_queue_xmit()

[Akira Yokosawa]

Hi,

On Wed, 4 May 2022 11:28:51 +0700,
Bagas Sanjaya wrote:
> On 5/4/22 08:03, Jakub Kicinski wrote:
[...]
>> Why drop almost half of the comment if the problem is just the ----
>> banner?
> 
> I can't think of preserving delineation between actual documentation
> and the quote without messing up kernel-doc.
Actually, it is possible.

See "Block Quotes" in ReST documentation at:
https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#block-quotes

kernel-doc is basically ReST within comment blocks with several kernel-doc
specific implicit/explicit markers.

        Thanks, Akira

> 
> Actually the "--BLG" signature is the culprit.

Re: [PATCH net-next] net/core: Remove comment quote for __dev_queue_xmit()

[Jakub Kicinski]

On Wed, 4 May 2022 22:43:12 +0900 Akira Yokosawa wrote:
> > I can't think of preserving delineation between actual documentation
> > and the quote without messing up kernel-doc.  

That's not what I'm complaining about, I'm saying that you rewrote 
the documentation. There were 3 paragraphs now there are 2.

> Actually, it is possible.
> 
> See "Block Quotes" in ReST documentation at:
> https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#block-quotes
> 
> kernel-doc is basically ReST within comment blocks with several kernel-doc
> specific implicit/explicit markers.

With all due respect I don't even know who (what?) "BLG" is.

Let's just get rid of the delineation and the signature and make 
the text of the quote normal documentation.

> > Actually the "--BLG" signature is the culprit.  

Re: [PATCH net-next] net/core: Remove comment quote for __dev_queue_xmit()

[Akira Yokosawa]

[+To: Ben]
[-Cc: unreachable addresses]

Hi,

On 2022/05/04 23:37,
Jakub Kicinski wrote:
> On Wed, 4 May 2022 22:43:12 +0900 Akira Yokosawa wrote:
>>> I can't think of preserving delineation between actual documentation
>>> and the quote without messing up kernel-doc.  
> 
> That's not what I'm complaining about, I'm saying that you rewrote 
> the documentation. There were 3 paragraphs now there are 2.
> 
>> Actually, it is possible.
>>
>> See "Block Quotes" in ReST documentation at:
>> https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#block-quotes
>>
>> kernel-doc is basically ReST within comment blocks with several kernel-doc
>> specific implicit/explicit markers.
> 
> With all due respect I don't even know who (what?) "BLG" is.

In case this might help, this comment block was added in commit
af191367a752 ("[NET]: Document ->hard_start_xmit() locking in
comments.") authored by Ben way back in 2005.

Ben, if you want to see the circumstances, here is a link to the lore
archive.
    https://lore.kernel.org/all/20220504073707.5bd851b0@kernel.org/#r

> 
> Let's just get rid of the delineation and the signature and make 
> the text of the quote normal documentation.

I'm not sure but Ben might be interested in helping rephrase the quote.

        Thanks, Akira

> 
>>> Actually the "--BLG" signature is the culprit.  
>