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From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH printk v7 06/35] printk: nbcon: Remove return value for write_atomic()
Date: Sun,  4 Aug 2024 02:57:09 +0206	[thread overview]
Message-ID: <20240804005138.3722656-7-john.ogness@linutronix.de> (raw)
In-Reply-To: <20240804005138.3722656-1-john.ogness@linutronix.de>

The return value of write_atomic() does not provide any useful
information. On the contrary, it makes things more complicated
for the caller to appropriately deal with the information.

Change write_atomic() to not have a return value. If the
message did not get printed due to loss of ownership, the
caller will notice this on its own. If ownership was not lost,
it will be assumed that the driver successfully printed the
message and the sequence number for that console will be
incremented.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
---
 include/linux/console.h |  2 +-
 kernel/printk/nbcon.c   | 15 +++++++--------
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/include/linux/console.h b/include/linux/console.h
index 31a8f5b85f5d..577b157fe4fb 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -345,7 +345,7 @@ struct console {
 	struct hlist_node	node;
 
 	/* nbcon console specific members */
-	bool			(*write_atomic)(struct console *con,
+	void			(*write_atomic)(struct console *con,
 						struct nbcon_write_context *wctxt);
 	atomic_t		__private nbcon_state;
 	atomic_long_t		__private nbcon_seq;
diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
index 931b8f086902..f279f839741a 100644
--- a/kernel/printk/nbcon.c
+++ b/kernel/printk/nbcon.c
@@ -885,7 +885,6 @@ static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt)
 	unsigned long con_dropped;
 	struct nbcon_state cur;
 	unsigned long dropped;
-	bool done;
 
 	/*
 	 * The printk buffers are filled within an unsafe section. This
@@ -925,16 +924,16 @@ static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt)
 	wctxt->unsafe_takeover = cur.unsafe_takeover;
 
 	if (con->write_atomic) {
-		done = con->write_atomic(con, wctxt);
+		con->write_atomic(con, wctxt);
 	} else {
-		nbcon_context_release(ctxt);
+		/*
+		 * This function should never be called for legacy consoles.
+		 * Handle it as if ownership was lost and try to continue.
+		 */
 		WARN_ON_ONCE(1);
-		done = false;
-	}
-
-	/* If not done, the emit was aborted. */
-	if (!done)
+		nbcon_context_release(ctxt);
 		return false;
+	}
 
 	/*
 	 * Since any dropped message was successfully output, reset the
-- 
2.39.2


  parent reply	other threads:[~2024-08-04  0:51 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-04  0:51 [PATCH printk v7 00/35] wire up write_atomic() printing John Ogness
2024-08-04  0:51 ` [PATCH printk v7 01/35] printk: Add notation to console_srcu locking John Ogness
2024-08-04  0:51 ` [PATCH printk v7 02/35] printk: nbcon: Consolidate alloc() and init() John Ogness
2024-08-05 14:39   ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 03/35] printk: Properly deal with nbcon consoles on seq init John Ogness
2024-08-04  0:51 ` [PATCH printk v7 04/35] printk: Check printk_deferred_enter()/_exit() usage John Ogness
2024-08-04  0:51 ` [PATCH printk v7 05/35] printk: nbcon: Clarify rules of the owner/waiter matching John Ogness
2024-08-04  0:51 ` John Ogness [this message]
2024-08-04  0:51 ` [PATCH printk v7 07/35] printk: nbcon: Add detailed doc for write_atomic() John Ogness
2024-08-04  0:51 ` [PATCH printk v7 08/35] printk: nbcon: Add callbacks to synchronize with driver John Ogness
2024-08-04  0:51 ` [PATCH printk v7 09/35] printk: nbcon: Use driver synchronization while (un)registering John Ogness
2024-08-04  0:51 ` [PATCH printk v7 10/35] serial: core: Provide low-level functions to lock port John Ogness
2024-08-04  0:51 ` [PATCH printk v7 11/35] serial: core: Introduce wrapper to set @uart_port->cons John Ogness
2024-08-04  0:51 ` [PATCH printk v7 12/35] console: Improve console_srcu_read_flags() comments John Ogness
2024-08-04  0:51 ` [PATCH printk v7 13/35] nbcon: Add API to acquire context for non-printing operations John Ogness
2024-08-04  0:51 ` [PATCH printk v7 14/35] serial: core: Acquire nbcon context in port->lock wrapper John Ogness
2024-08-04  0:51 ` [PATCH printk v7 15/35] printk: nbcon: Do not rely on proxy headers John Ogness
2024-08-04  0:51 ` [PATCH printk v7 16/35] printk: Make console_is_usable() available to nbcon.c John Ogness
2024-08-04  0:51 ` [PATCH printk v7 17/35] printk: Let console_is_usable() handle nbcon John Ogness
2024-08-04  0:51 ` [PATCH printk v7 18/35] printk: Add @flags argument for console_is_usable() John Ogness
2024-08-04  0:51 ` [PATCH printk v7 19/35] printk: nbcon: Add helper to assign priority based on CPU state John Ogness
2024-08-04  0:51 ` [PATCH printk v7 20/35] printk: nbcon: Provide function to flush using write_atomic() John Ogness
2024-08-05 14:59   ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 21/35] printk: Track registered boot consoles John Ogness
2024-08-04  0:51 ` [PATCH printk v7 22/35] printk: nbcon: Use nbcon consoles in console_flush_all() John Ogness
2024-08-04  0:51 ` [PATCH printk v7 23/35] printk: Add is_printk_legacy_deferred() John Ogness
2024-08-05 15:03   ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 24/35] printk: nbcon: Flush new records on device_release() John Ogness
2024-08-05 15:31   ` Petr Mladek
2024-08-07  1:15     ` John Ogness
2024-08-07 12:48       ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 25/35] printk: Flush nbcon consoles first on panic John Ogness
2024-08-06  8:31   ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 26/35] printk: nbcon: Add unsafe flushing " John Ogness
2024-08-04  0:51 ` [PATCH printk v7 27/35] printk: Avoid console_lock dance if no legacy or boot consoles John Ogness
2024-08-06  8:40   ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 28/35] printk: Track nbcon consoles John Ogness
2024-08-04  0:51 ` [PATCH printk v7 29/35] printk: Coordinate direct printing in panic John Ogness
2024-08-06  9:59   ` Petr Mladek
2024-08-06 17:29     ` Linus Torvalds
2024-08-06 12:17   ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 30/35] printk: Add helper for flush type logic John Ogness
2024-08-07 11:39   ` Petr Mladek
2024-08-07 14:11     ` John Ogness
2024-08-08  9:03       ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 31/35] printk: nbcon: Implement emergency sections John Ogness
2024-08-07 12:52   ` Petr Mladek
2024-08-04  0:51 ` [PATCH printk v7 32/35] panic: Mark emergency section in warn John Ogness
2024-08-04  0:51 ` [PATCH printk v7 33/35] panic: Mark emergency section in oops John Ogness
2024-08-04  0:51 ` [PATCH printk v7 34/35] rcu: Mark emergency sections in rcu stalls John Ogness
2024-08-04  0:51 ` [PATCH printk v7 35/35] lockdep: Mark emergency sections in lockdep splats John Ogness

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