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SubjectRe: [PATCH 3/8] tty: don't store semi-state into tty drivers
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On 7/23/21 9:43 AM, Jiri Slaby wrote:
> When a tty driver pointer is used as a return value of struct
> console's device() hook, don't store a semi-state into global variable
> which holds the tty driver. It could mean console::device() would return
> a bogus value. This is important esp. after the next patch where we
> switch from alloc_tty_driver to tty_alloc_driver. tty_alloc_driver
> returns ERR_PTR in case of error and that might have unexpected results
> as the code doesn't expect this.
>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> Cc: Helge Deller <deller@gmx.de>
> Cc: Chris Zankel <chris@zankel.net>
> Cc: Max Filippov <jcmvbkbc@gmail.com>
> Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Cc: Felipe Balbi <balbi@kernel.org>
> ---
> arch/m68k/emu/nfcon.c | 27 +++++++++++---------
> arch/parisc/kernel/pdc_cons.c | 28 +++++++++++----------
> arch/xtensa/platforms/iss/console.c | 33 +++++++++++++-----------
> drivers/tty/amiserial.c | 35 ++++++++++++++------------
> drivers/tty/ehv_bytechan.c | 28 ++++++++++++---------
> drivers/tty/hvc/hvsi.c | 35 ++++++++++++++------------
> drivers/usb/gadget/function/u_serial.c | 32 ++++++++++++-----------
> 7 files changed, 119 insertions(+), 99 deletions(-)
>
...

You may add:

Acked-by: Helge Deller <deller@gmx.de> # parisc

to the whole series (specifically patches 3, 4 and 8) regarding the parisc changes.

Thank you!
Helge

>
> diff --git a/arch/parisc/kernel/pdc_cons.c b/arch/parisc/kernel/pdc_cons.c
> index 39ccad063533..650cb01203de 100644
> --- a/arch/parisc/kernel/pdc_cons.c
> +++ b/arch/parisc/kernel/pdc_cons.c
> @@ -138,6 +138,7 @@ static struct tty_driver *pdc_console_tty_driver;
>
> static int __init pdc_console_tty_driver_init(void)
> {
> + struct tty_driver *driver;
> int err;
>
> /* Check if the console driver is still registered.
> @@ -160,31 +161,32 @@ static int __init pdc_console_tty_driver_init(void)
> printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
> pdc_cons.flags &= ~CON_BOOT;
>
> - pdc_console_tty_driver = alloc_tty_driver(1);
> -
> - if (!pdc_console_tty_driver)
> + driver = alloc_tty_driver(1);
> + if (!driver)
> return -ENOMEM;
>
> tty_port_init(&tty_port);
>
> - pdc_console_tty_driver->driver_name = "pdc_cons";
> - pdc_console_tty_driver->name = "ttyB";
> - pdc_console_tty_driver->major = MUX_MAJOR;
> - pdc_console_tty_driver->minor_start = 0;
> - pdc_console_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
> - pdc_console_tty_driver->init_termios = tty_std_termios;
> - pdc_console_tty_driver->flags = TTY_DRIVER_REAL_RAW |
> + driver->driver_name = "pdc_cons";
> + driver->name = "ttyB";
> + driver->major = MUX_MAJOR;
> + driver->minor_start = 0;
> + driver->type = TTY_DRIVER_TYPE_SYSTEM;
> + driver->init_termios = tty_std_termios;
> + driver->flags = TTY_DRIVER_REAL_RAW |
> TTY_DRIVER_RESET_TERMIOS;
> - tty_set_operations(pdc_console_tty_driver, &pdc_console_tty_ops);
> - tty_port_link_device(&tty_port, pdc_console_tty_driver, 0);
> + tty_set_operations(driver, &pdc_console_tty_ops);
> + tty_port_link_device(&tty_port, driver, 0);
>
> - err = tty_register_driver(pdc_console_tty_driver);
> + err = tty_register_driver(driver);
> if (err) {
> printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
> tty_port_destroy(&tty_port);
> return err;
> }
>
> + pdc_console_tty_driver = driver;
> +
> return 0;
> }
> device_initcall(pdc_console_tty_driver_init);
...

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