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Message-ID: <a23f380657a9933e5c8961971266ea892835ea48.1763492585.git.chris@chrisdown.name>
Date: Wed, 19 Nov 2025 03:06:58 +0800
From: Chris Down <chris@...isdown.name>
To: Petr Mladek <pmladek@...e.com>
Cc: linux-kernel@...r.kernel.org,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Sergey Senozhatsky <senozhatsky@...omium.org>,
Steven Rostedt <rostedt@...dmis.org>,
John Ogness <john.ogness@...utronix.de>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Tony Lindgren <tony.lindgren@...ux.intel.com>, kernel-team@...com
Subject: [PATCH v7 02/13] printk: Use effective loglevel for suppression and
extended console state
In preparation for supporting per-console loglevels, modify
printk_get_next_message() to accept the effective console loglevel
instead of individual arguments that mimic console fields. This keeps
the function console-agnostic and lockless as intended, while still
allowing per-console loglevel support to be added in later patches.
devkmsg_read() uses CONSOLE_LOGLEVEL_MOTORMOUTH to never suppress
messages. All other consoles pass their effective loglevel (currently
console_loglevel, will be per-console in later patches).
Reviewed-by: Petr Mladek <pmladek@...e.com>
Signed-off-by: Chris Down <chris@...isdown.name>
---
kernel/printk/internal.h | 2 +-
kernel/printk/nbcon.c | 2 +-
kernel/printk/printk.c | 22 +++++++++++++---------
3 files changed, 15 insertions(+), 11 deletions(-)
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index f72bbfa266d6..1ed86577896c 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -333,7 +333,7 @@ struct printk_message {
};
bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
- bool is_extended, bool may_supress);
+ bool is_extended, int con_eff_level);
#ifdef CONFIG_PRINTK
void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped);
diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
index 558ef3177976..eb4c8faa213d 100644
--- a/kernel/printk/nbcon.c
+++ b/kernel/printk/nbcon.c
@@ -993,7 +993,7 @@ static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt, bool use_a
if (!nbcon_context_enter_unsafe(ctxt))
return false;
- ctxt->backlog = printk_get_next_message(&pmsg, ctxt->seq, is_extended, true);
+ ctxt->backlog = printk_get_next_message(&pmsg, ctxt->seq, is_extended, console_loglevel);
if (!ctxt->backlog)
return nbcon_context_exit_unsafe(ctxt);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index ff8b6dbb29a7..745f89a18189 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -807,7 +807,8 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
if (ret)
return ret;
- if (!printk_get_next_message(&pmsg, atomic64_read(&user->seq), true, false)) {
+ if (!printk_get_next_message(&pmsg, atomic64_read(&user->seq), true,
+ CONSOLE_LOGLEVEL_MOTORMOUTH)) {
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
goto out;
@@ -825,7 +826,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
*/
ret = wait_event_interruptible(log_wait,
printk_get_next_message(&pmsg, atomic64_read(&user->seq), true,
- false)); /* LMM(devkmsg_read:A) */
+ CONSOLE_LOGLEVEL_MOTORMOUTH)); /* LMM(devkmsg_read:A) */
if (ret)
goto out;
}
@@ -1279,9 +1280,9 @@ module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(ignore_loglevel,
"ignore loglevel setting (prints all kernel messages to the console)");
-static bool suppress_message_printing(int level)
+static bool suppress_message_printing(int level, int con_eff_level)
{
- return (level >= console_loglevel && !ignore_loglevel);
+ return (level >= con_eff_level && !ignore_loglevel);
}
#ifdef CONFIG_BOOT_PRINTK_DELAY
@@ -2115,7 +2116,7 @@ int printk_delay_msec __read_mostly;
static inline void printk_delay(int level)
{
/* If the message is forced (e.g. panic), we must delay */
- if (!is_printk_force_console() && suppress_message_printing(level))
+ if (!is_printk_force_console() && suppress_message_printing(level, console_loglevel))
return;
boot_delay_msec();
@@ -2946,14 +2947,15 @@ void console_prepend_replay(struct printk_message *pmsg)
* @is_extended specifies if the message should be formatted for extended
* console output.
*
- * @may_supress specifies if records may be skipped based on loglevel.
+ * @con_eff_level is the effective console loglevel to use for suppression
+ * checks.
*
* Returns false if no record is available. Otherwise true and all fields
* of @pmsg are valid. (See the documentation of struct printk_message
* for information about the @pmsg fields.)
*/
bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
- bool is_extended, bool may_suppress)
+ bool is_extended, int con_eff_level)
{
struct printk_buffers *pbufs = pmsg->pbufs;
const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf);
@@ -2982,13 +2984,14 @@ bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
pmsg->seq = r.info->seq;
pmsg->dropped = r.info->seq - seq;
+
force_con = r.info->flags & LOG_FORCE_CON;
/*
* Skip records that are not forced to be printed on consoles and that
* has level above the console loglevel.
*/
- if (!force_con && may_suppress && suppress_message_printing(r.info->level))
+ if (!force_con && suppress_message_printing(r.info->level, con_eff_level))
goto out;
if (is_extended) {
@@ -3064,7 +3067,8 @@ static bool console_emit_next_record(struct console *con, bool *handover, int co
*handover = false;
- if (!printk_get_next_message(&pmsg, con->seq, is_extended, true))
+ if (!printk_get_next_message(&pmsg, con->seq, is_extended,
+ console_loglevel))
return false;
con->dropped += pmsg.dropped;
--
2.51.2
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