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Subject[PATCH v4 1/3] printk: Move console matching logic into a separate function
Date
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This moves the loop that tries to match a newly registered console
with the command line or add_preferred_console list into a separate
helper, in order to be able to call it multiple times in subsequent
patches.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
kernel/printk/printk.c | 105 ++++++++++++++++++++++++++++++-------------------
1 file changed, 65 insertions(+), 40 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index fada22dc4ab6..0ebcdf53e75d 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -280,6 +280,7 @@ static struct console *exclusive_console;
static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];

static int preferred_console = -1;
+static bool has_preferred_console;
int console_set_on_cmdline;
EXPORT_SYMBOL(console_set_on_cmdline);

@@ -2626,6 +2627,60 @@ static int __init keep_bootcon_setup(char *str)

early_param("keep_bootcon", keep_bootcon_setup);

+/*
+ * This is called by register_console() to try to match
+ * the newly registered console with any of the ones selected
+ * by either the command line or add_preferred_console() and
+ * setup/enable it.
+ *
+ * Care need to be taken with consoles that are statically
+ * enabled such as netconsole
+ */
+static int try_enable_new_console(struct console *newcon)
+{
+ struct console_cmdline *c;
+ int i;
+
+ for (i = 0, c = console_cmdline;
+ i < MAX_CMDLINECONSOLES && c->name[0];
+ i++, c++) {
+ if (!newcon->match ||
+ newcon->match(newcon, c->name, c->index, c->options) != 0) {
+ /* default matching */
+ BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name));
+ if (strcmp(c->name, newcon->name) != 0)
+ continue;
+ if (newcon->index >= 0 &&
+ newcon->index != c->index)
+ continue;
+ if (newcon->index < 0)
+ newcon->index = c->index;
+
+ if (_braille_register_console(newcon, c))
+ return 0;
+
+ if (newcon->setup &&
+ newcon->setup(newcon, c->options) != 0)
+ return -EIO;
+ }
+ newcon->flags |= CON_ENABLED;
+ if (i == preferred_console) {
+ newcon->flags |= CON_CONSDEV;
+ has_preferred_console = true;
+ }
+ return 0;
+ }
+
+ /*
+ * Some consoles, such as pstore and netconsole, can be enabled even
+ * without matching.
+ */
+ if (newcon->flags & CON_ENABLED)
+ return 0;
+
+ return -ENOENT;
+}
+
/*
* The console driver calls this routine during kernel initialization
* to register the console printing procedure with printk() and to
@@ -2647,11 +2702,9 @@ early_param("keep_bootcon", keep_bootcon_setup);
*/
void register_console(struct console *newcon)
{
- int i;
unsigned long flags;
struct console *bcon = NULL;
- struct console_cmdline *c;
- static bool has_preferred;
+ int err;

if (console_drivers)
for_each_console(bcon)
@@ -2678,15 +2731,15 @@ void register_console(struct console *newcon)
if (console_drivers && console_drivers->flags & CON_BOOT)
bcon = console_drivers;

- if (!has_preferred || bcon || !console_drivers)
- has_preferred = preferred_console >= 0;
+ if (!has_preferred_console || bcon || !console_drivers)
+ has_preferred_console = preferred_console >= 0;

/*
* See if we want to use this console driver. If we
* didn't select a console we take the first one
* that registers here.
*/
- if (!has_preferred) {
+ if (!has_preferred_console) {
if (newcon->index < 0)
newcon->index = 0;
if (newcon->setup == NULL ||
@@ -2694,47 +2747,19 @@ void register_console(struct console *newcon)
newcon->flags |= CON_ENABLED;
if (newcon->device) {
newcon->flags |= CON_CONSDEV;
- has_preferred = true;
+ has_preferred_console = true;
}
}
}

/*
- * See if this console matches one we selected on
- * the command line.
+ * See if this console matches one we selected on
+ * the command line or if it was statically enabled
*/
- for (i = 0, c = console_cmdline;
- i < MAX_CMDLINECONSOLES && c->name[0];
- i++, c++) {
- if (!newcon->match ||
- newcon->match(newcon, c->name, c->index, c->options) != 0) {
- /* default matching */
- BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name));
- if (strcmp(c->name, newcon->name) != 0)
- continue;
- if (newcon->index >= 0 &&
- newcon->index != c->index)
- continue;
- if (newcon->index < 0)
- newcon->index = c->index;
-
- if (_braille_register_console(newcon, c))
- return;
-
- if (newcon->setup &&
- newcon->setup(newcon, c->options) != 0)
- break;
- }
-
- newcon->flags |= CON_ENABLED;
- if (i == preferred_console) {
- newcon->flags |= CON_CONSDEV;
- has_preferred = true;
- }
- break;
- }
+ err = try_enable_new_console(newcon);

- if (!(newcon->flags & CON_ENABLED))
+ /* printk() messages are not printed to the Braille console. */
+ if (err || newcon->flags & CON_BRL)
return;

/*
--
2.16.4
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