[PATCH 1/3] printk: use CONFIG_CONSOLE_LOGLEVEL_* directly

Masahiro Yamada
2021-02-02T07:08:52Z

CONSOLE_LOGLEVEL_DEFAULT is nothing more than a shorthand of
CONFIG_CONSOLE_LOGLEVEL_DEFAULT.

When you change CONFIG_CONSOLE_LOGLEVEL_DEFAULT from Kconfig, almost
all objects are rebuilt because CONFIG_CONSOLE_LOGLEVEL_DEFAULT is
used in <linux/printk.h>, which is included from most of source files.

In fact, there are only 4 users of CONSOLE_LOGLEVEL_DEFAULT:

arch/x86/platform/uv/uv_nmi.c
drivers/firmware/efi/libstub/efi-stub-helper.c
drivers/tty/sysrq.c
kernel/printk/printk.c

So, when you change CONFIG_CONSOLE_LOGLEVEL_DEFAULT and rebuild the
kernel, it is enough to recompile those 4 files.

Remove the CONSOLE_LOGLEVEL_DEFAULT definition from <linux/printk.h>,
and use CONFIG_CONSOLE_LOGLEVEL_DEFAULT directly.

With this, the build system will rebuild the minimal number of objects.

Steps to confirm it:

[1] Do the full build
[2] Change CONFIG_CONSOLE_LOGLEVEL_DEFAULT from 'make menuconfig' etc.
[3] Rebuild

$ make
SYNC include/config/auto.conf
CALL scripts/checksyscalls.sh
CALL scripts/atomic/check-atomics.sh
DESCEND objtool
CHK include/generated/compile.h
CC kernel/printk/printk.o
AR kernel/printk/built-in.a
AR kernel/built-in.a
CC drivers/tty/sysrq.o
AR drivers/tty/built-in.a
CC drivers/firmware/efi/libstub/efi-stub-helper.o
STUBCPY drivers/firmware/efi/libstub/efi-stub-helper.stub.o
AR drivers/firmware/efi/libstub/lib.a
AR drivers/built-in.a
GEN .version
CHK include/generated/compile.h
UPD include/generated/compile.h
CC init/version.o
AR init/built-in.a
LD vmlinux.o
...

For the same reason, do likewise for CONSOLE_LOGLEVEL_QUIET and
MESSAGE_LOGLEVEL_DEFAULT.

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

arch/x86/platform/uv/uv_nmi.c | 2 +-
drivers/firmware/efi/libstub/efi-stub-helper.c | 6 +++---
drivers/tty/sysrq.c | 4 ++--
drivers/video/fbdev/core/fbcon.c | 2 +-
drivers/video/fbdev/efifb.c | 2 +-
include/linux/printk.h | 10 ----------
init/main.c | 2 +-
kernel/printk/printk.c | 6 +++---
8 files changed, 12 insertions(+), 22 deletions(-)

diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c
index eafc530c8767..4751299c7416 100644
--- a/arch/x86/platform/uv/uv_nmi.c
+++ b/arch/x86/platform/uv/uv_nmi.c
@@ -100,7 +100,7 @@ static cpumask_var_t uv_nmi_cpu_mask;
* Default is all stack dumps go to the console and buffer.
* Lower level to send to log buffer only.
*/
-static int uv_nmi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
+static int uv_nmi_loglevel = CONFIG_CONSOLE_LOGLEVEL_DEFAULT;
module_param_named(dump_loglevel, uv_nmi_loglevel, int, 0644);

/*
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index aa8da0a49829..3e8d8f706589 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -12,7 +12,7 @@
#include <linux/ctype.h>
#include <linux/efi.h>
#include <linux/kernel.h>
-#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */
+#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_DEBUG */
#include <asm/efi.h>
#include <asm/setup.h>

@@ -21,7 +21,7 @@
bool efi_nochunk;
bool efi_nokaslr = !IS_ENABLED(CONFIG_RANDOMIZE_BASE);
bool efi_noinitrd;
-int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
+int efi_loglevel = CONFIG_CONSOLE_LOGLEVEL_DEFAULT;
bool efi_novamap;

static bool efi_nosoftreserve;
@@ -213,7 +213,7 @@ efi_status_t efi_parse_options(char const *cmdline)
if (!strcmp(param, "nokaslr")) {
efi_nokaslr = true;
} else if (!strcmp(param, "quiet")) {
- efi_loglevel = CONSOLE_LOGLEVEL_QUIET;
+ efi_loglevel = CONFIG_CONSOLE_LOGLEVEL_QUIET;
} else if (!strcmp(param, "noinitrd")) {
efi_noinitrd = true;
} else if (!strcmp(param, "efi") && val) {
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 959f9e121cc6..e0ae7793155e 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -103,7 +103,7 @@ static void sysrq_handle_loglevel(int key)
int i;

i = key - '0';
- console_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
+ console_loglevel = CONFIG_CONSOLE_LOGLEVEL_DEFAULT;
pr_info("Loglevel set to %d\n", i);
console_loglevel = i;
}
@@ -584,7 +584,7 @@ void __handle_sysrq(int key, bool check_mask)
* routing in the consumers of /proc/kmsg.
*/
orig_log_level = console_loglevel;
- console_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
+ console_loglevel = CONFIG_CONSOLE_LOGLEVEL_DEFAULT;

op_p = __sysrq_get_key_op(key);
if (op_p) {
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index bf61598bf1c3..75b97268663f 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -1043,7 +1043,7 @@ static void fbcon_init(struct vc_data *vc, int init)

info = registered_fb[con2fb_map[vc->vc_num]];

- if (logo_shown < 0 && console_loglevel <= CONSOLE_LOGLEVEL_QUIET)
+ if (logo_shown < 0 && console_loglevel <= CONFIG_CONSOLE_LOGLEVEL_QUIET)
logo_shown = FBCON_LOGO_DONTSHOW;

if (vc != svc || logo_shown == FBCON_LOGO_DONTSHOW ||
diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
index e57c00824965..dfb234a0a59d 100644
--- a/drivers/video/fbdev/efifb.c
+++ b/drivers/video/fbdev/efifb.c
@@ -160,7 +160,7 @@ static void efifb_show_boot_graphics(struct fb_info *info)
}

/* Avoid flashing the logo if we're going to print std probe messages */
- if (console_loglevel > CONSOLE_LOGLEVEL_QUIET)
+ if (console_loglevel > CONFIG_CONSOLE_LOGLEVEL_QUIET)
return;

/* bgrt_tab.status is unreliable, so we don't check it */
diff --git a/include/linux/printk.h b/include/linux/printk.h
index fe7eb2351610..fd34b3aa2f90 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -46,22 +46,12 @@ static inline const char *printk_skip_headers(const char *buffer)

#define CONSOLE_EXT_LOG_MAX 8192

-/* printk's without a loglevel use this.. */
-#define MESSAGE_LOGLEVEL_DEFAULT CONFIG_MESSAGE_LOGLEVEL_DEFAULT
-
/* We show everything that is MORE important than this.. */
#define CONSOLE_LOGLEVEL_SILENT 0 /* Mum's the word */
#define CONSOLE_LOGLEVEL_MIN 1 /* Minimum loglevel we let people use */
#define CONSOLE_LOGLEVEL_DEBUG 10 /* issue debug messages */
#define CONSOLE_LOGLEVEL_MOTORMOUTH 15 /* You can't shut this one up */

-/*
- * Default used to be hard-coded at 7, quiet used to be hardcoded at 4,
- * we're now allowing both to be set from kernel config.
- */
-#define CONSOLE_LOGLEVEL_DEFAULT CONFIG_CONSOLE_LOGLEVEL_DEFAULT
-#define CONSOLE_LOGLEVEL_QUIET CONFIG_CONSOLE_LOGLEVEL_QUIET
-
extern int console_printk[];

#define console_loglevel (console_printk[0])
diff --git a/init/main.c b/init/main.c
index c68d784376ca..4dfcbf7f24c6 100644
--- a/init/main.c
+++ b/init/main.c
@@ -236,7 +236,7 @@ static int __init debug_kernel(char *str)

static int __init quiet_kernel(char *str)
{
- console_loglevel = CONSOLE_LOGLEVEL_QUIET;
+ console_loglevel = CONFIG_CONSOLE_LOGLEVEL_QUIET;
return 0;
}

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 5a95c688621f..92b93340905c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -61,10 +61,10 @@
#include "internal.h"

int console_printk[4] = {
- CONSOLE_LOGLEVEL_DEFAULT, /* console_loglevel */
- MESSAGE_LOGLEVEL_DEFAULT, /* default_message_loglevel */
+ CONFIG_CONSOLE_LOGLEVEL_DEFAULT, /* console_loglevel */
+ CONFIG_MESSAGE_LOGLEVEL_DEFAULT, /* default_message_loglevel */
CONSOLE_LOGLEVEL_MIN, /* minimum_console_loglevel */
- CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */
+ CONFIG_CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */
};
EXPORT_SYMBOL_GPL(console_printk);

--
2.27.0