From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Alexey Gladkov <legion@kernel.org>
Cc: Jiri Slaby <jirislaby@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
kbd@lists.linux.dev, linux-api@vger.kernel.org,
linux-fbdev@vger.kernel.org, linux-serial@vger.kernel.org,
Helge Deller <deller@gmx.de>
Subject: Re: [RESEND PATCH v3 1/2] VT: Add KDFONTINFO ioctl
Date: Wed, 10 Apr 2024 19:11:03 +0200 [thread overview]
Message-ID: <2024041027-overload-striking-c9a5@gregkh> (raw)
In-Reply-To: <Zha-X8QS_8L9eF0r@example.org>
On Wed, Apr 10, 2024 at 06:29:19PM +0200, Alexey Gladkov wrote:
> On Wed, Apr 03, 2024 at 07:27:55AM +0200, Jiri Slaby wrote:
> > On 02. 04. 24, 15:19, Alexey Gladkov wrote:
> > >>> --- a/include/uapi/linux/kd.h
> > >>> +++ b/include/uapi/linux/kd.h
> > ...
> > >>> +struct console_font_info {
> > >>> + unsigned int min_width, min_height; /* minimal font size */
> > >>> + unsigned int max_width, max_height; /* maximum font size */
> > >>> + unsigned int flags; /* KD_FONT_INFO_FLAG_* */
> > >>
> > >> This does not look like a well-defined™ and extendable uapi structure.
> > >> While it won't change anything here, still use fixed-length __u32.
> > >>
> > >> And you should perhaps add some reserved fields. Do not repeat the same
> > >> mistakes as your predecessors with the current kd uapi.
> > >
> > > I thought about it, but I thought it would be overengineering.
> >
> > It would not. UAPI structs are set in stone once released.
> >
> > And in this case, it's likely you would want to know more info about
> > fonts in the future.
> >
> > > Can you suggest how best to do this?
> >
> > Given you have flags in there already (to state that the structure
> > contains more), just add an array of u32 reserved[] space. 3 or 5, I
> > would say (to align the struct to 64bit).
>
> struct console_font_info {
> __u32 min_width, min_height; /* minimal font size */
> __u32 max_width, max_height; /* maximum font size */
> __u32 flags; /* KD_FONT_INFO_FLAG_* */
> __u32 reserved[5]; /* This field is reserved forfuture use. Must be 0. */
> };
>
> So, struct should be like this ?
>
> I wouldn't add the version to the flags. Maybe it would be better to add a
> separate field with the version?
Versions do not work for ioctls, just use flags for stuff. And you
might want to put flags first?
thanks,
greg k-h
next prev parent reply other threads:[~2024-04-10 17:11 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1708960303.git.legion@kernel.org>
2024-03-12 14:23 ` [PATCH v3 0/2] VT: Add ability to get font requirements legion
2024-03-12 14:23 ` [PATCH v3 1/2] VT: Add KDFONTINFO ioctl legion
2024-03-15 9:15 ` Helge Deller
2024-03-12 14:23 ` [PATCH v3 2/2] VT: Allow to get max font width and height legion
2024-03-13 17:40 ` Oleg Bulatov
2024-04-02 11:09 ` Jiri Slaby
2024-03-15 9:16 ` Helge Deller
2024-04-02 10:32 ` [RESEND PATCH v3 0/2] VT: Add ability to get font requirements Alexey Gladkov
2024-04-02 10:32 ` [RESEND PATCH v3 1/2] VT: Add KDFONTINFO ioctl Alexey Gladkov
2024-04-02 11:02 ` Jiri Slaby
2024-04-02 13:19 ` Alexey Gladkov
2024-04-03 5:27 ` Jiri Slaby
2024-04-10 16:29 ` Alexey Gladkov
2024-04-10 17:11 ` Greg Kroah-Hartman [this message]
2024-04-02 17:50 ` [PATCH v4 0/3] VT: Add ability to get font requirements Alexey Gladkov
2024-04-02 17:50 ` [PATCH v4 1/3] VT: Use macros to define ioctls Alexey Gladkov
2024-04-02 17:50 ` [PATCH v4 2/3] VT: Add KDFONTINFO ioctl Alexey Gladkov
2024-04-03 4:55 ` Greg Kroah-Hartman
2024-04-03 5:05 ` Jiri Slaby
2024-04-10 16:36 ` Alexey Gladkov
2024-04-11 3:53 ` Jiri Slaby
2024-04-02 17:50 ` [PATCH v4 3/3] VT: Allow to get max font width and height Alexey Gladkov
2024-04-17 17:37 ` [PATCH v5 0/3] VT: Add ability to get font requirements Alexey Gladkov
2024-04-17 17:37 ` [PATCH v5 1/3] VT: Use macros to define ioctls Alexey Gladkov
2024-04-18 6:18 ` Greg Kroah-Hartman
2024-04-17 17:37 ` [PATCH v5 2/3] VT: Add KDFONTINFO ioctl Alexey Gladkov
2024-04-17 19:31 ` Helge Deller
2024-04-18 10:45 ` Alexey Gladkov
2024-04-25 10:33 ` Helge Deller
2024-04-25 11:06 ` Alexey Gladkov
2024-04-25 11:35 ` Helge Deller
2024-04-18 6:18 ` Greg Kroah-Hartman
2024-04-18 10:27 ` Alexey Gladkov
2024-04-17 17:37 ` [PATCH v5 3/3] VT: Allow to get max font width and height Alexey Gladkov
2024-04-02 10:32 ` [RESEND PATCH v3 2/2] " Alexey Gladkov
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