diff mbox series

[v2,1/2] console: Remove dummy con_font_op() callback implementations

Message ID c5563eeea36aae7bd72ea2e985bc610d585ece40.1604306433.git.yepeilin.cs@gmail.com
State New
Headers show
Series [v2,1/2] console: Remove dummy con_font_op() callback implementations | expand

Commit Message

Peilin Ye Nov. 2, 2020, 9:36 a.m. UTC
`struct console_font` is a UAPI structure, thus ideally should not be
used for kernel internal abstraction. Remove some dummy .con_font_set,
.con_font_default and .con_font_copy `struct consw` callback
implementations, to make it cleaner.

Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Change in v2:
  - [v2 2/2] no longer Cc: stable, so do not Cc: stable

Context: https://lore.kernel.org/lkml/CAKMK7uFY2zv0adjKJ_ORVFT7Zzwn075MaU0rEU7_FuqENLR=UA@mail.gmail.com/

 drivers/usb/misc/sisusbvga/sisusb_con.c | 21 ---------------------
 drivers/video/console/dummycon.c        | 20 --------------------
 2 files changed, 41 deletions(-)

Comments

Jiri Slaby Nov. 2, 2020, 9:47 a.m. UTC | #1
On 02. 11. 20, 10:36, Peilin Ye wrote:
> `struct console_font` is a UAPI structure, thus ideally should not be

> used for kernel internal abstraction. Remove some dummy .con_font_set,

> .con_font_default and .con_font_copy `struct consw` callback

> implementations, to make it cleaner.


ESEMANTIC_ERROR.

1) What do you refer to with the last "it"?

2) What's the purpose of mentioning struct console_font at all?

3) Could you clarify whether you checked it is safe to remove the hooks?

4) All the hooks now return ENOSYS for both consoles (and not 0). Is 
this intentional?

I know answers to the first 3 questions, but you need to elaborate a bit 
in the commit log to connect those sentences. Esp. for people not 
dealing with the code on a daily basis. Ad 4) I am not sure.

> Suggested-by: Daniel Vetter <daniel@ffwll.ch>

> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>

> ---

> Change in v2:

>    - [v2 2/2] no longer Cc: stable, so do not Cc: stable

> 

> Context: https://lore.kernel.org/lkml/CAKMK7uFY2zv0adjKJ_ORVFT7Zzwn075MaU0rEU7_FuqENLR=UA@mail.gmail.com/

> 

>   drivers/usb/misc/sisusbvga/sisusb_con.c | 21 ---------------------

>   drivers/video/console/dummycon.c        | 20 --------------------

>   2 files changed, 41 deletions(-)

> 

> diff --git a/drivers/usb/misc/sisusbvga/sisusb_con.c b/drivers/usb/misc/sisusbvga/sisusb_con.c

> index c63e545fb105..dfa0d5ce6012 100644

> --- a/drivers/usb/misc/sisusbvga/sisusb_con.c

> +++ b/drivers/usb/misc/sisusbvga/sisusb_con.c

> @@ -1345,24 +1345,6 @@ static int sisusbdummycon_blank(struct vc_data *vc, int blank, int mode_switch)

>   	return 0;

>   }

>   

> -static int sisusbdummycon_font_set(struct vc_data *vc,

> -				   struct console_font *font,

> -				   unsigned int flags)

> -{

> -	return 0;

> -}

> -

> -static int sisusbdummycon_font_default(struct vc_data *vc,

> -				       struct console_font *font, char *name)

> -{

> -	return 0;

> -}

> -

> -static int sisusbdummycon_font_copy(struct vc_data *vc, int con)

> -{

> -	return 0;

> -}

> -

>   static const struct consw sisusb_dummy_con = {

>   	.owner =		THIS_MODULE,

>   	.con_startup =		sisusbdummycon_startup,

> @@ -1375,9 +1357,6 @@ static const struct consw sisusb_dummy_con = {

>   	.con_scroll =		sisusbdummycon_scroll,

>   	.con_switch =		sisusbdummycon_switch,

>   	.con_blank =		sisusbdummycon_blank,

> -	.con_font_set =		sisusbdummycon_font_set,

> -	.con_font_default =	sisusbdummycon_font_default,

> -	.con_font_copy =	sisusbdummycon_font_copy,

>   };

>   

>   int

> diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c

> index 2a0d0bda7faa..f1711b2f9ff0 100644

> --- a/drivers/video/console/dummycon.c

> +++ b/drivers/video/console/dummycon.c

> @@ -124,23 +124,6 @@ static int dummycon_switch(struct vc_data *vc)

>   	return 0;

>   }

>   

> -static int dummycon_font_set(struct vc_data *vc, struct console_font *font,

> -			     unsigned int flags)

> -{

> -	return 0;

> -}

> -

> -static int dummycon_font_default(struct vc_data *vc,

> -				 struct console_font *font, char *name)

> -{

> -	return 0;

> -}

> -

> -static int dummycon_font_copy(struct vc_data *vc, int con)

> -{

> -	return 0;

> -}

> -

>   /*

>    *  The console `switch' structure for the dummy console

>    *

> @@ -159,8 +142,5 @@ const struct consw dummy_con = {

>   	.con_scroll =	dummycon_scroll,

>   	.con_switch =	dummycon_switch,

>   	.con_blank =	dummycon_blank,

> -	.con_font_set =	dummycon_font_set,

> -	.con_font_default =	dummycon_font_default,

> -	.con_font_copy =	dummycon_font_copy,

>   };

>   EXPORT_SYMBOL_GPL(dummy_con);

> 



-- 
js
suse labs
Daniel Vetter Nov. 2, 2020, 10:13 a.m. UTC | #2
On Mon, Nov 02, 2020 at 10:47:55AM +0100, Jiri Slaby wrote:
> On 02. 11. 20, 10:36, Peilin Ye wrote:

> > `struct console_font` is a UAPI structure, thus ideally should not be

> > used for kernel internal abstraction. Remove some dummy .con_font_set,

> > .con_font_default and .con_font_copy `struct consw` callback

> > implementations, to make it cleaner.

> 

> ESEMANTIC_ERROR.

> 

> 1) What do you refer to with the last "it"?

> 

> 2) What's the purpose of mentioning struct console_font at all?

> 

> 3) Could you clarify whether you checked it is safe to remove the hooks?

> 

> 4) All the hooks now return ENOSYS for both consoles (and not 0). Is this

> intentional?

> 

> I know answers to the first 3 questions, but you need to elaborate a bit in

> the commit log to connect those sentences. Esp. for people not dealing with

> the code on a daily basis. Ad 4) I am not sure.


Yup the behaviour change from 4) needs to be called out. I think this
should then also be done as part of the large patch series to remove the
dummy functions from all console drivers.

I don't expect the errno change to cause trouble, and it's the more honest
errno - changing fonts not supported is the truth. But if it is, we can
patch that up appropriately when we get a regression report. That's kinda
unavoidable with old crufty uapi like this one here.

Also a bikeshed: Additional information like the patch changelog or
reasons why you do something is imo best to include in the commit message
itself. It ends up looking a bit less tidy sometimes, but often there's
crucial information in these parts that was accidentally left out from the
commit message.
Thanks, Daniel
> 

> > Suggested-by: Daniel Vetter <daniel@ffwll.ch>

> > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>

> > ---

> > Change in v2:

> >    - [v2 2/2] no longer Cc: stable, so do not Cc: stable

> > 

> > Context: https://lore.kernel.org/lkml/CAKMK7uFY2zv0adjKJ_ORVFT7Zzwn075MaU0rEU7_FuqENLR=UA@mail.gmail.com/

> > 

> >   drivers/usb/misc/sisusbvga/sisusb_con.c | 21 ---------------------

> >   drivers/video/console/dummycon.c        | 20 --------------------

> >   2 files changed, 41 deletions(-)

> > 

> > diff --git a/drivers/usb/misc/sisusbvga/sisusb_con.c b/drivers/usb/misc/sisusbvga/sisusb_con.c

> > index c63e545fb105..dfa0d5ce6012 100644

> > --- a/drivers/usb/misc/sisusbvga/sisusb_con.c

> > +++ b/drivers/usb/misc/sisusbvga/sisusb_con.c

> > @@ -1345,24 +1345,6 @@ static int sisusbdummycon_blank(struct vc_data *vc, int blank, int mode_switch)

> >   	return 0;

> >   }

> > -static int sisusbdummycon_font_set(struct vc_data *vc,

> > -				   struct console_font *font,

> > -				   unsigned int flags)

> > -{

> > -	return 0;

> > -}

> > -

> > -static int sisusbdummycon_font_default(struct vc_data *vc,

> > -				       struct console_font *font, char *name)

> > -{

> > -	return 0;

> > -}

> > -

> > -static int sisusbdummycon_font_copy(struct vc_data *vc, int con)

> > -{

> > -	return 0;

> > -}

> > -

> >   static const struct consw sisusb_dummy_con = {

> >   	.owner =		THIS_MODULE,

> >   	.con_startup =		sisusbdummycon_startup,

> > @@ -1375,9 +1357,6 @@ static const struct consw sisusb_dummy_con = {

> >   	.con_scroll =		sisusbdummycon_scroll,

> >   	.con_switch =		sisusbdummycon_switch,

> >   	.con_blank =		sisusbdummycon_blank,

> > -	.con_font_set =		sisusbdummycon_font_set,

> > -	.con_font_default =	sisusbdummycon_font_default,

> > -	.con_font_copy =	sisusbdummycon_font_copy,

> >   };

> >   int

> > diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c

> > index 2a0d0bda7faa..f1711b2f9ff0 100644

> > --- a/drivers/video/console/dummycon.c

> > +++ b/drivers/video/console/dummycon.c

> > @@ -124,23 +124,6 @@ static int dummycon_switch(struct vc_data *vc)

> >   	return 0;

> >   }

> > -static int dummycon_font_set(struct vc_data *vc, struct console_font *font,

> > -			     unsigned int flags)

> > -{

> > -	return 0;

> > -}

> > -

> > -static int dummycon_font_default(struct vc_data *vc,

> > -				 struct console_font *font, char *name)

> > -{

> > -	return 0;

> > -}

> > -

> > -static int dummycon_font_copy(struct vc_data *vc, int con)

> > -{

> > -	return 0;

> > -}

> > -

> >   /*

> >    *  The console `switch' structure for the dummy console

> >    *

> > @@ -159,8 +142,5 @@ const struct consw dummy_con = {

> >   	.con_scroll =	dummycon_scroll,

> >   	.con_switch =	dummycon_switch,

> >   	.con_blank =	dummycon_blank,

> > -	.con_font_set =	dummycon_font_set,

> > -	.con_font_default =	dummycon_font_default,

> > -	.con_font_copy =	dummycon_font_copy,

> >   };

> >   EXPORT_SYMBOL_GPL(dummy_con);

> > 

> 

> 

> -- 

> js

> suse labs


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
Peilin Ye Nov. 2, 2020, 10:52 a.m. UTC | #3
On Mon, Nov 02, 2020 at 11:13:47AM +0100, Daniel Vetter wrote:
> On Mon, Nov 02, 2020 at 10:47:55AM +0100, Jiri Slaby wrote:

> > On 02. 11. 20, 10:36, Peilin Ye wrote:

> > > `struct console_font` is a UAPI structure, thus ideally should not be

> > > used for kernel internal abstraction. Remove some dummy .con_font_set,

> > > .con_font_default and .con_font_copy `struct consw` callback

> > > implementations, to make it cleaner.

> > 

> > ESEMANTIC_ERROR.

> > 

> > 1) What do you refer to with the last "it"?

> > 

> > 2) What's the purpose of mentioning struct console_font at all?

> > 

> > 3) Could you clarify whether you checked it is safe to remove the hooks?


I see. I will try to elaborate in future patches, thank you!

> > 4) All the hooks now return ENOSYS for both consoles (and not 0). Is this

> > intentional?

> > 

> > I know answers to the first 3 questions, but you need to elaborate a bit in

> > the commit log to connect those sentences. Esp. for people not dealing with

> > the code on a daily basis. Ad 4) I am not sure.

> 

> Yup the behaviour change from 4) needs to be called out. I think this

> should then also be done as part of the large patch series to remove the

> dummy functions from all console drivers.

> 

> I don't expect the errno change to cause trouble, and it's the more honest

> errno - changing fonts not supported is the truth. But if it is, we can

> patch that up appropriately when we get a regression report. That's kinda

> unavoidable with old crufty uapi like this one here.

> 

> Also a bikeshed: Additional information like the patch changelog or

> reasons why you do something is imo best to include in the commit message

> itself. It ends up looking a bit less tidy sometimes, but often there's

> crucial information in these parts that was accidentally left out from the

> commit message.


Sure, I will try to include sufficient information for one to easily
understand what I'm trying to do with a patch. Thank you,

Peilin
diff mbox series

Patch

diff --git a/drivers/usb/misc/sisusbvga/sisusb_con.c b/drivers/usb/misc/sisusbvga/sisusb_con.c
index c63e545fb105..dfa0d5ce6012 100644
--- a/drivers/usb/misc/sisusbvga/sisusb_con.c
+++ b/drivers/usb/misc/sisusbvga/sisusb_con.c
@@ -1345,24 +1345,6 @@  static int sisusbdummycon_blank(struct vc_data *vc, int blank, int mode_switch)
 	return 0;
 }
 
-static int sisusbdummycon_font_set(struct vc_data *vc,
-				   struct console_font *font,
-				   unsigned int flags)
-{
-	return 0;
-}
-
-static int sisusbdummycon_font_default(struct vc_data *vc,
-				       struct console_font *font, char *name)
-{
-	return 0;
-}
-
-static int sisusbdummycon_font_copy(struct vc_data *vc, int con)
-{
-	return 0;
-}
-
 static const struct consw sisusb_dummy_con = {
 	.owner =		THIS_MODULE,
 	.con_startup =		sisusbdummycon_startup,
@@ -1375,9 +1357,6 @@  static const struct consw sisusb_dummy_con = {
 	.con_scroll =		sisusbdummycon_scroll,
 	.con_switch =		sisusbdummycon_switch,
 	.con_blank =		sisusbdummycon_blank,
-	.con_font_set =		sisusbdummycon_font_set,
-	.con_font_default =	sisusbdummycon_font_default,
-	.con_font_copy =	sisusbdummycon_font_copy,
 };
 
 int
diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c
index 2a0d0bda7faa..f1711b2f9ff0 100644
--- a/drivers/video/console/dummycon.c
+++ b/drivers/video/console/dummycon.c
@@ -124,23 +124,6 @@  static int dummycon_switch(struct vc_data *vc)
 	return 0;
 }
 
-static int dummycon_font_set(struct vc_data *vc, struct console_font *font,
-			     unsigned int flags)
-{
-	return 0;
-}
-
-static int dummycon_font_default(struct vc_data *vc,
-				 struct console_font *font, char *name)
-{
-	return 0;
-}
-
-static int dummycon_font_copy(struct vc_data *vc, int con)
-{
-	return 0;
-}
-
 /*
  *  The console `switch' structure for the dummy console
  *
@@ -159,8 +142,5 @@  const struct consw dummy_con = {
 	.con_scroll =	dummycon_scroll,
 	.con_switch =	dummycon_switch,
 	.con_blank =	dummycon_blank,
-	.con_font_set =	dummycon_font_set,
-	.con_font_default =	dummycon_font_default,
-	.con_font_copy =	dummycon_font_copy,
 };
 EXPORT_SYMBOL_GPL(dummy_con);