[PATCH v2 5/9] printk: Separate code for enabling console

[Petr Mladek]

There are several code paths which try to enable a newly registered
console. Move the logic into a separate try_enable_console() function.

It simplifies a bit the long register_console() function definition.

Also followup patches are going to add even more code paths. And it will
be easier to use "return" when it does not make sense to try other
variants.

The patch does not change the existing behavior.

Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>
---
 kernel/printk/printk.c | 64 ++++++++++++++++++++++++------------------
 1 file changed, 36 insertions(+), 28 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 7a3bbb0cb794..2543c810efcb 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -4040,6 +4040,41 @@ static void try_enable_default_console(struct console *newcon)
 		newcon->flags |= CON_CONSDEV;
 }
 
+#define console_first()				\
+	hlist_entry(console_list.first, struct console, node)
+
+static int try_enable_console(struct console *newcon)
+{
+	int err;
+
+	/*
+	 * See if we want to enable this console driver by default.
+	 *
+	 * Nope when a console is preferred by the command line, device
+	 * tree, or SPCR.
+	 *
+	 * The first real console with tty binding (driver) wins. More
+	 * consoles might get enabled before the right one is found.
+	 *
+	 * Note that a console with tty binding will have CON_CONSDEV
+	 * flag set and will be first in the list.
+	 */
+	if (preferred_dev_console < 0) {
+		if (hlist_empty(&console_list) || !console_first()->device ||
+		    console_first()->flags & CON_BOOT) {
+			try_enable_default_console(newcon);
+		}
+	}
+
+	/* See if this console matches one we selected on the command line */
+	err = try_enable_preferred_console(newcon, true);
+	if (err != -ENOENT)
+		return err;
+
+	/* If not, try to match against the platform default(s) */
+	return try_enable_preferred_console(newcon, false);
+}
+
 /* Return the starting sequence number for a newly registered console. */
 static u64 get_init_console_seq(struct console *newcon, bool bootcon_registered)
 {
@@ -4114,9 +4149,6 @@ static u64 get_init_console_seq(struct console *newcon, bool bootcon_registered)
 	return init_seq;
 }
 
-#define console_first()				\
-	hlist_entry(console_list.first, struct console, node)
-
 static int unregister_console_locked(struct console *console);
 
 /*
@@ -4178,31 +4210,7 @@ void register_console(struct console *newcon)
 			goto unlock;
 	}
 
-	/*
-	 * See if we want to enable this console driver by default.
-	 *
-	 * Nope when a console is preferred by the command line, device
-	 * tree, or SPCR.
-	 *
-	 * The first real console with tty binding (driver) wins. More
-	 * consoles might get enabled before the right one is found.
-	 *
-	 * Note that a console with tty binding will have CON_CONSDEV
-	 * flag set and will be first in the list.
-	 */
-	if (preferred_dev_console < 0) {
-		if (hlist_empty(&console_list) || !console_first()->device ||
-		    console_first()->flags & CON_BOOT) {
-			try_enable_default_console(newcon);
-		}
-	}
-
-	/* See if this console matches one we selected on the command line */
-	err = try_enable_preferred_console(newcon, true);
-
-	/* If not, try to match against the platform default(s) */
-	if (err == -ENOENT)
-		err = try_enable_preferred_console(newcon, false);
+	err = try_enable_console(newcon);
 
 	/* printk() messages are not printed to the Braille console. */
 	if (err || newcon->flags & CON_BRL) {
-- 
2.53.0