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SubjectRe: [PATCH v4 1/3] tty: rename tty_kopen() and add new function tty_kopen_shared()
On Tue, Dec 17, 2019 at 07:08:47PM +0100, Jacek Anaszewski wrote:
> Hi Uwe,
>
> I wanted to test the set but unfortunately this
> patch does not apply. See below for the apparent reason.
>
> On 12/17/19 5:58 PM, Uwe Kleine-König wrote:
> > Introduce a new function tty_kopen_shared() that yields a struct
> > tty_struct. The semantic difference to tty_kopen() is that the tty is
> > expected to be used already. So rename tty_kopen() to
> > tty_kopen_exclusive() for clearness, adapt the single user and put the
> > common code in a new static helper function.
> >
> > tty_kopen_shared is to be used to implement an LED trigger for tty
> > devices in one of the next patches.
> >
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> > ---
> > drivers/staging/speakup/spk_ttyio.c | 2 +-
> > drivers/tty/tty_io.c | 58 ++++++++++++++++++++---------
> > include/linux/tty.h | 5 ++-
> > 3 files changed, 44 insertions(+), 21 deletions(-)
> >
> > diff --git a/drivers/staging/speakup/spk_ttyio.c b/drivers/staging/speakup/spk_ttyio.c
> > index 5a9eff08cb96..e9db06eae875 100644
> > --- a/drivers/staging/speakup/spk_ttyio.c
> > +++ b/drivers/staging/speakup/spk_ttyio.c
> > @@ -147,7 +147,7 @@ static int spk_ttyio_initialise_ldisc(struct spk_synth *synth)
> > if (ret)
> > return ret;
> >
> > - tty = tty_kopen(dev);
> > + tty = tty_kopen_exclusive(dev);
> > if (IS_ERR(tty))
> > return PTR_ERR(tty);
> >
> > diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
> > index a1453fe10862..b718666ce73c 100644
> > --- a/drivers/tty/tty_io.c
> > +++ b/drivers/tty/tty_io.c
> > @@ -1875,22 +1875,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
> > return driver;
> > }
> >
> > -/**
> > - * tty_kopen - open a tty device for kernel
> > - * @device: dev_t of device to open
> > - *
> > - * Opens tty exclusively for kernel. Performs the driver lookup,
> > - * makes sure it's not already opened and performs the first-time
> > - * tty initialization.
> > - *
> > - * Returns the locked initialized &tty_struct
> > - *
> > - * Claims the global tty_mutex to serialize:
> > - * - concurrent first-time tty initialization
> > - * - concurrent tty driver removal w/ lookup
> > - * - concurrent tty removal from driver table
> > - */
> > -struct tty_struct *tty_kopen(dev_t device)
> > +static struct tty_struct *tty_kopen(dev_t device, int shared)
> > {
> > struct tty_struct *tty;
> > struct tty_driver *driver;
>
> In mainline, even in v5.5-rc2 we have here NULL assignment:
>
> struct tty_driver *driver = NULL;

This is based on a patch that is already in my tty-testing tree and that
was posted earlier. It should show up in linux-next in a day or so.

thanks,

greg k-h

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