[PATCH AUTOSEL 5.4 037/109] hvsi: don't panic on tty_register_driver failure

Sasha Levin
2021-09-09T12:56:14Z

From: Jiri Slaby <jslaby@suse.cz>

[ Upstream commit 7ccbdcc4d08a6d7041e4849219bbb12ffa45db4c ]

The alloc_tty_driver failure is handled gracefully in hvsi_init. But
tty_register_driver is not. panic is called if that one fails.

So handle the failure of tty_register_driver gracefully too. This will
keep at least the console functional as it was enabled earlier by
console_initcall in hvsi_console_init. Instead of shooting down the
whole system.

This means, we disable interrupts and restore hvsi_wait back to
poll_for_state().

Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723074317.32690-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/hvc/hvsi.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/hvc/hvsi.c b/drivers/tty/hvc/hvsi.c
index 66f95f758be0..73226337f561 100644
--- a/drivers/tty/hvc/hvsi.c
+++ b/drivers/tty/hvc/hvsi.c
@@ -1038,7 +1038,7 @@ static const struct tty_operations hvsi_ops = {

static int __init hvsi_init(void)
{
- int i;
+ int i, ret;

hvsi_driver = alloc_tty_driver(hvsi_count);
if (!hvsi_driver)
@@ -1069,12 +1069,25 @@ static int __init hvsi_init(void)
}
hvsi_wait = wait_for_state; /* irqs active now */

- if (tty_register_driver(hvsi_driver))
- panic("Couldn't register hvsi console driver\n");
+ ret = tty_register_driver(hvsi_driver);
+ if (ret) {
+ pr_err("Couldn't register hvsi console driver\n");
+ goto err_free_irq;
+ }

printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);

return 0;
+err_free_irq:
+ hvsi_wait = poll_for_state;
+ for (i = 0; i < hvsi_count; i++) {
+ struct hvsi_struct *hp = &hvsi_ports[i];
+
+ free_irq(hp->virq, hp);
+ }
+ tty_driver_kref_put(hvsi_driver);
+
+ return ret;
}
device_initcall(hvsi_init);

--
2.30.2