Re: [PATCH] m68k/atari - ide: do not register interrupt if host->get_lock is set

[David Miller]

From: Michael Schmitz 
Date: Thu, 6 Mar 2014 19:47:06 +1300

> Thanks Dave,
> 
>>> On m68k, host->get_lock is used to both lock and register the
>>> interrupt
>>> that the IDE host shares with other device drivers. Registering the
>>> IDE interrupt handler in ide-probe.c results in duplicating the
>>> interrupt registered (once via host->get lock, and also via
>>> init_irq()),
>>> and may result in IDE accepting interrupts even when another driver
>>> has
>>> locked the interrupt hardware. This opens the whole locking scheme up
>>> to races.
>>>
>>> host->get_lock is set on m68k only, so other drivers' behaviour is not
>>> changed.
>>>
>>> Signed-off-by: Michael Schmitz 
>>
>> It's a bit kludgy, but minimal and correct.
> 
> Would you have preferred to use a host flag instead?

I looked into that, we are out of host flags.  We'd either need to expand
the flags value to 64-bits or add another u32.

That's overkill for this.
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Re: [PATCH 1/3] m68k/atari - convert atari_scsi falcon_get_lock() to use wait_event()

[Geert Uytterhoeven]

On Sat, Mar 1, 2014 at 8:51 AM, Michael Schmitz  wrote:
> sleep_on is known broken and going away. The atari_scsi driver is one of
> two remaining users in the falcon_get_lock() function, which is a rather
> crazy piece of code. This does not attempt to fix the driver's locking
> scheme in general, but at least prevents falcon_get_lock from going to
> sleep when no other thread holds the same lock or tries to get it,
> and we no longer schedule with irqs disabled.
>
> MSch: fixed completion conditions missed in Arnds' original RFC patch.
>
> Signed-off-by: Arnd Bergmann 
> Acked-by: Michael Schmitz 
> Cc: Geert Uytterhoeven 
> Cc: James E.J. Bottomley 
> Cc: linux-s...@vger.kernel.org

Thanks, applied with original authorship attribution, original subject
matching SCSI oneline summary style, and proper SoB.

Will queue for 3.15.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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