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Message-ID: <ba47efbe432cf33cb358a027a2266296e2cfe89e.1730133890.git.chris@chrisdown.name>
Date: Mon, 28 Oct 2024 16:45:34 +0000
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 v6 02/11] printk: Use struct console for suppression and
extended console state
In preparation for supporting per-console loglevels, modify
printk_get_next_message() to accept the console itself instead of
individual arguments that mimic its fields. As part of the upcoming
per-console loglevel support we need the console object here anyway, so
it makes sense to amortise this now.
devkmsg_read() has special behaviour here, but all other consoles follow
the same patterns and can have their extension/suppression states
determined from their struct console.
Signed-off-by: Chris Down <chris@...isdown.name>
---
kernel/printk/internal.h | 4 ++--
kernel/printk/nbcon.c | 2 +-
kernel/printk/printk.c | 33 ++++++++++++++++++++-------------
3 files changed, 23 insertions(+), 16 deletions(-)
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 3fcb48502adb..58ad209e0310 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -328,8 +328,8 @@ struct printk_message {
};
bool other_cpu_in_panic(void);
-bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
- bool is_extended, bool may_supress);
+bool printk_get_next_message(struct printk_message *pmsg, struct console *con,
+ u64 seq);
#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 fd12efcc4aed..5ae1155c34d3 100644
--- a/kernel/printk/nbcon.c
+++ b/kernel/printk/nbcon.c
@@ -974,7 +974,7 @@ 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, con, ctxt->seq);
if (!ctxt->backlog)
return nbcon_context_exit_unsafe(ctxt);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index d6159f1c5b29..dfe7011b863a 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -833,7 +833,7 @@ 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, NULL, atomic64_read(&user->seq))) {
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
goto out;
@@ -850,8 +850,8 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
* This pairs with __wake_up_klogd:A.
*/
ret = wait_event_interruptible(log_wait,
- printk_get_next_message(&pmsg, atomic64_read(&user->seq), true,
- false)); /* LMM(devkmsg_read:A) */
+ printk_get_next_message(&pmsg, NULL,
+ atomic64_read(&user->seq))); /* LMM(devkmsg_read:A) */
if (ret)
goto out;
}
@@ -2925,20 +2925,19 @@ void console_prepend_replay(struct printk_message *pmsg)
* @pmsg will contain the formatted result. @pmsg->pbufs must point to a
* struct printk_buffers.
*
+ * @con is the console in question. Only @con->flags and @con->level are
+ * guaranteed to be valid at this point. Note especially well that con->seq is
+ * not yet guaranteed to be consistent with @seq.
+ *
* @seq is the record to read and format. If it is not available, the next
* valid record is read.
*
- * @is_extended specifies if the message should be formatted for extended
- * console output.
- *
- * @may_supress specifies if records may be skipped based on loglevel.
- *
* 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 printk_get_next_message(struct printk_message *pmsg, struct console *con,
+ u64 seq)
{
struct printk_buffers *pbufs = pmsg->pbufs;
const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf);
@@ -2948,6 +2947,14 @@ bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
struct printk_info info;
struct printk_record r;
size_t len = 0;
+ bool is_extended;
+
+ if (con) {
+ is_extended = console_srcu_read_flags(con) & CON_EXTENDED;
+ } else {
+ /* Used only by devkmsg_read(). */
+ is_extended = true;
+ }
/*
* Formatting extended messages requires a separate buffer, so use the
@@ -2967,8 +2974,8 @@ bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
pmsg->seq = r.info->seq;
pmsg->dropped = r.info->seq - seq;
- /* Skip record that has level above the console loglevel. */
- if (may_suppress && suppress_message_printing(r.info->level))
+ /* Never suppress when used in devkmsg_read() */
+ if (con && suppress_message_printing(r.info->level))
goto out;
if (is_extended) {
@@ -3044,7 +3051,7 @@ 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, con->seq))
return false;
con->dropped += pmsg.dropped;
--
2.46.0
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