Re: [PATCH v4 2/3] printk: Change type of CONFIG_BASE_SMALL to bool

From: Masahiro Yamada <masahiroy@kernel.org>
To: Yoann Congal <yoann.congal@smile.fr>
Cc: linux-fsdevel@vger.kernel.org, linux-kbuild@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
	x86@kernel.org, "André Almeida" <andrealmeid@igalia.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Darren Hart" <dvhart@infradead.org>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Davidlohr Bueso" <dave@stgolabs.net>,
	"Geert Uytterhoeven" <geert@linux-m68k.org>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"H . Peter Anvin" <hpa@zytor.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Jiri Slaby" <jirislaby@kernel.org>,
	"John Ogness" <john.ogness@linutronix.de>,
	"Josh Triplett" <josh@joshtriplett.org>,
	"Matthew Wilcox" <willy@infradead.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Petr Mladek" <pmladek@suse.com>,
	"Sergey Senozhatsky" <senozhatsky@chromium.org>,
	"Steven Rostedt" <rostedt@goodmis.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>
Subject: Re: [PATCH v4 2/3] printk: Change type of CONFIG_BASE_SMALL to bool
Date: Wed, 7 Feb 2024 08:05:07 +0900	[thread overview]
Message-ID: <CAK7LNATzkZSK=hYbShOER=PnR7KVUBrDN=RL2Yyw413uMueiXw@mail.gmail.com> (raw)
In-Reply-To: <20240206001333.1710070-3-yoann.congal@smile.fr>

On Tue, Feb 6, 2024 at 9:13 AM Yoann Congal <yoann.congal@smile.fr> wrote:
>
> CONFIG_BASE_SMALL is currently a type int but is only used as a boolean.
>
> So, change its type to bool and adapt all usages:
> CONFIG_BASE_SMALL == 0 becomes !IS_ENABLED(CONFIG_BASE_SMALL) and
> CONFIG_BASE_SMALL != 0 becomes  IS_ENABLED(CONFIG_BASE_SMALL).
>
> Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
> ---
> NB: This is preliminary work for the following patch removing
> CONFIG_BASE_FULL (now equivalent to !CONFIG_BASE_SMALL)
>
> v3->v4:
> * Split "switch CONFIG_BASE_SMALL to bool" (this patch) and "Remove the redundant
>   config" into two patches
> * keep CONFIG_BASE_SMALL instead of CONFIG_BASE_FULL
> ---
>  arch/x86/include/asm/mpspec.h | 6 +++---
>  drivers/tty/vt/vc_screen.c    | 2 +-
>  include/linux/threads.h       | 4 ++--
>  include/linux/udp.h           | 2 +-
>  include/linux/xarray.h        | 2 +-
>  init/Kconfig                  | 8 ++++----
>  kernel/futex/core.c           | 2 +-
>  kernel/user.c                 | 2 +-
>  8 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/include/asm/mpspec.h b/arch/x86/include/asm/mpspec.h
> index 4b0f98a8d338d..c01d3105840cf 100644
> --- a/arch/x86/include/asm/mpspec.h
> +++ b/arch/x86/include/asm/mpspec.h
> @@ -15,10 +15,10 @@ extern int pic_mode;
>   * Summit or generic (i.e. installer) kernels need lots of bus entries.
>   * Maximum 256 PCI busses, plus 1 ISA bus in each of 4 cabinets.
>   */
> -#if CONFIG_BASE_SMALL == 0
> -# define MAX_MP_BUSSES         260
> -#else
> +#ifdef CONFIG_BASE_SMALL
>  # define MAX_MP_BUSSES         32
> +#else
> +# define MAX_MP_BUSSES         260
>  #endif
>
>  #define MAX_IRQ_SOURCES                256
> diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
> index 67e2cb7c96eec..da33c6c4691c0 100644
> --- a/drivers/tty/vt/vc_screen.c
> +++ b/drivers/tty/vt/vc_screen.c
> @@ -51,7 +51,7 @@
>  #include <asm/unaligned.h>
>
>  #define HEADER_SIZE    4u
> -#define CON_BUF_SIZE (CONFIG_BASE_SMALL ? 256 : PAGE_SIZE)
> +#define CON_BUF_SIZE (IS_ENABLED(CONFIG_BASE_SMALL) ? 256 : PAGE_SIZE)
>
>  /*
>   * Our minor space:
> diff --git a/include/linux/threads.h b/include/linux/threads.h
> index c34173e6c5f18..1674a471b0b4c 100644
> --- a/include/linux/threads.h
> +++ b/include/linux/threads.h
> @@ -25,13 +25,13 @@
>  /*
>   * This controls the default maximum pid allocated to a process
>   */
> -#define PID_MAX_DEFAULT (CONFIG_BASE_SMALL ? 0x1000 : 0x8000)
> +#define PID_MAX_DEFAULT (IS_ENABLED(CONFIG_BASE_SMALL) ? 0x1000 : 0x8000)
>
>  /*
>   * A maximum of 4 million PIDs should be enough for a while.
>   * [NOTE: PID/TIDs are limited to 2^30 ~= 1 billion, see FUTEX_TID_MASK.]
>   */
> -#define PID_MAX_LIMIT (CONFIG_BASE_SMALL ? PAGE_SIZE * 8 : \
> +#define PID_MAX_LIMIT (IS_ENABLED(CONFIG_BASE_SMALL) ? PAGE_SIZE * 8 : \
>         (sizeof(long) > 4 ? 4 * 1024 * 1024 : PID_MAX_DEFAULT))
>
>  /*
> diff --git a/include/linux/udp.h b/include/linux/udp.h
> index d04188714dca1..b456417fb4515 100644
> --- a/include/linux/udp.h
> +++ b/include/linux/udp.h
> @@ -24,7 +24,7 @@ static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
>  }
>
>  #define UDP_HTABLE_SIZE_MIN_PERNET     128
> -#define UDP_HTABLE_SIZE_MIN            (CONFIG_BASE_SMALL ? 128 : 256)
> +#define UDP_HTABLE_SIZE_MIN            (IS_ENABLED(CONFIG_BASE_SMALL) ? 128 : 256)
>  #define UDP_HTABLE_SIZE_MAX            65536
>
>  static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
> diff --git a/include/linux/xarray.h b/include/linux/xarray.h
> index cb571dfcf4b16..3f81ee5f9fb9c 100644
> --- a/include/linux/xarray.h
> +++ b/include/linux/xarray.h
> @@ -1141,7 +1141,7 @@ static inline void xa_release(struct xarray *xa, unsigned long index)
>   * doubled the number of slots per node, we'd get only 3 nodes per 4kB page.
>   */
>  #ifndef XA_CHUNK_SHIFT
> -#define XA_CHUNK_SHIFT         (CONFIG_BASE_SMALL ? 4 : 6)
> +#define XA_CHUNK_SHIFT         (IS_ENABLED(CONFIG_BASE_SMALL) ? 4 : 6)
>  #endif
>  #define XA_CHUNK_SIZE          (1UL << XA_CHUNK_SHIFT)
>  #define XA_CHUNK_MASK          (XA_CHUNK_SIZE - 1)
> diff --git a/init/Kconfig b/init/Kconfig
> index d50ebd2a2ce42..d4b16cad98502 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -734,7 +734,7 @@ config LOG_CPU_MAX_BUF_SHIFT
>         int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
>         depends on SMP
>         range 0 21
> -       default 0 if BASE_SMALL != 0
> +       default 0 if BASE_SMALL
>         default 12
>         depends on PRINTK
>         help
> @@ -1941,9 +1941,9 @@ config RT_MUTEXES
>         default y if PREEMPT_RT
>
>  config BASE_SMALL
> -       int
> -       default 0 if BASE_FULL
> -       default 1 if !BASE_FULL
> +       bool
> +       default y if !BASE_FULL
> +       default n

The shortest form would be:

config BASE_SMALL
        def_bool !BASE_FULL

But, that is not a big deal, as this hunk will
be removed by 3/3.

Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>

-- 
Best Regards
Masahiro Yamada