From: Lionel Debieve <[email protected]>
The lock is a sleeping lock and local_irq_save() is not the
standard implementation now. Working for both -RT and non
RT.
Signed-off-by: Lionel Debieve <[email protected]>
---
drivers/tty/serial/st-asc.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index 379e5bd..1815423 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -803,13 +803,12 @@ static void asc_console_write(struct console *co, const char *s, unsigned count)
int locked = 1;
u32 intenable;
- local_irq_save(flags);
if (port->sysrq)
locked = 0; /* asc_interrupt has already claimed the lock */
else if (oops_in_progress)
- locked = spin_trylock(&port->lock);
+ locked = spin_trylock_irqsave(&port->lock, flags);
else
- spin_lock(&port->lock);
+ spin_lock_irqsave(&port->lock, flags);
/*
* Disable interrupts so we don't get the IRQ line bouncing
@@ -827,8 +826,7 @@ static void asc_console_write(struct console *co, const char *s, unsigned count)
asc_out(port, ASC_INTEN, intenable);
if (locked)
- spin_unlock(&port->lock);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&port->lock, flags);
}
static int asc_console_setup(struct console *co, char *options)
--
2.7.4
On Tue, 21 Mar 2017 17:05:40 +0100
<[email protected]> wrote:
> From: Lionel Debieve <[email protected]>
>
> The lock is a sleeping lock and local_irq_save() is not the
> standard implementation now. Working for both -RT and non
> RT.
If this is for both RT and non RT then the patch subject should just be
[PATCH] and not [PATCH RT] as the latter tells upstream folks not to
bother.
>
> Signed-off-by: Lionel Debieve <[email protected]>
> ---
> drivers/tty/serial/st-asc.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
> index 379e5bd..1815423 100644
> --- a/drivers/tty/serial/st-asc.c
> +++ b/drivers/tty/serial/st-asc.c
> @@ -803,13 +803,12 @@ static void asc_console_write(struct console
> *co, const char *s, unsigned count) int locked = 1;
> u32 intenable;
>
> - local_irq_save(flags);
> if (port->sysrq)
> locked = 0; /* asc_interrupt has already claimed the
> lock */ else if (oops_in_progress)
> - locked = spin_trylock(&port->lock);
> + locked = spin_trylock_irqsave(&port->lock, flags);
> else
> - spin_lock(&port->lock);
> + spin_lock_irqsave(&port->lock, flags);
>
> /*
> * Disable interrupts so we don't get the IRQ line bouncing
I'm nervous about the above comment, which in full is:
/*
* Disable interrupts so we don't get the IRQ line bouncing
* up and down while interrupts are disabled.
*/
I'm not sure if disabling interrupts helps on an SMP system. This patch
does change what happens when port->sysrq is set. But I'm not sure we
care.
-- Steve
> @@ -827,8 +826,7 @@ static void asc_console_write(struct console *co,
> const char *s, unsigned count) asc_out(port, ASC_INTEN, intenable);
>
> if (locked)
> - spin_unlock(&port->lock);
> - local_irq_restore(flags);
> + spin_unlock_irqrestore(&port->lock, flags);
> }
>
> static int asc_console_setup(struct console *co, char *options)
On Tue, 21 Mar 2017, Steven Rostedt wrote:
> > /*
> > * Disable interrupts so we don't get the IRQ line bouncing
>
> I'm nervous about the above comment, which in full is:
>
> /*
> * Disable interrupts so we don't get the IRQ line bouncing
> * up and down while interrupts are disabled.
> */
>
> I'm not sure if disabling interrupts helps on an SMP system. This patch
> does change what happens when port->sysrq is set. But I'm not sure we
> care.
It disables interrupts at the device level which obviously helps whether on
SMP or not.
Thanks,
tglx
On Tue, 21 Mar 2017 19:51:47 +0100 (CET)
Thomas Gleixner <[email protected]> wrote:
> On Tue, 21 Mar 2017, Steven Rostedt wrote:
> > > /*
> > > * Disable interrupts so we don't get the IRQ line
> > > bouncing
> >
> > I'm nervous about the above comment, which in full is:
> >
> > /*
> > * Disable interrupts so we don't get the IRQ line bouncing
> > * up and down while interrupts are disabled.
> > */
> >
> > I'm not sure if disabling interrupts helps on an SMP system. This
> > patch does change what happens when port->sysrq is set. But I'm not
> > sure we care.
>
> It disables interrupts at the device level which obviously helps
> whether on SMP or not.
>
OK, so this has nothing to do with the local_irq_save() that is being
removed, which would be fine then.
-- Steve
Just to agree with Thomas.
Do you want me to resend the patch without RT tag?
BR,
Lionel
On 03/21/2017 09:15 PM, Steven Rostedt wrote:
> On Tue, 21 Mar 2017 19:51:47 +0100 (CET)
> Thomas Gleixner <[email protected]> wrote:
>
>> On Tue, 21 Mar 2017, Steven Rostedt wrote:
>>>> /*
>>>> * Disable interrupts so we don't get the IRQ line
>>>> bouncing
>>> I'm nervous about the above comment, which in full is:
>>>
>>> /*
>>> * Disable interrupts so we don't get the IRQ line bouncing
>>> * up and down while interrupts are disabled.
>>> */
>>>
>>> I'm not sure if disabling interrupts helps on an SMP system. This
>>> patch does change what happens when port->sysrq is set. But I'm not
>>> sure we care.
>> It disables interrupts at the device level which obviously helps
>> whether on SMP or not.
>>
> OK, so this has nothing to do with the local_irq_save() that is being
> removed, which would be fine then.
>
>
> -- Steve
>
On Wed, 22 Mar 2017 08:43:50 +0000
Lionel DEBIEVE <[email protected]> wrote:
> Just to agree with Thomas.
>
> Do you want me to resend the patch without RT tag?
>
Yes please. And hopefully it will be picked up in mainline.
-- Steve
OK, resend without.
BR
Lionel
-----Original Message-----
From: Steven Rostedt [mailto:[email protected]]
Sent: mercredi 22 mars 2017 17:11
To: Lionel DEBIEVE <[email protected]>
Cc: Thomas Gleixner <[email protected]>; [email protected]; [email protected]; [email protected]; Patrice CHOTARD <[email protected]>; Greg Kroah-Hartman <[email protected]>; Jiri Slaby <[email protected]>
Subject: Re: [PATCH RT] tty: serial: st-asc: Make the locking RT aware
On Wed, 22 Mar 2017 08:43:50 +0000
Lionel DEBIEVE <[email protected]> wrote:
> Just to agree with Thomas.
>
> Do you want me to resend the patch without RT tag?
>
Yes please. And hopefully it will be picked up in mainline.
-- Steve