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Re: use of preempt_count instead of in_atomic() at leds-gpio.c

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From: Tetsuo Handa
Subject: Re: use of preempt_count instead of in_atomic() at leds-gpio.c
Date: Friday, March 21, 2008 - 8:11 am

Hello.


So, it is impossible to know whether I am inside a spinlock or not.
OK. That's not what I want to do.

I want to make sure that my code (not a device driver) is called only from a context
where use of down()/mutex_lock()/kmalloc(GFP_KERNEL)/get_user_pages()/kmap() etc. are permitted.
Is "if (in_atomic()) return;" check a correct method for avoiding deadlocks
when my code was accidentally called from a context
where use of down()/mutex_lock()/kmalloc(GFP_KERNEL)/get_user_pages()/kmap() etc. are not permitted?
I'm assuming that in_atomic() returns nonzero whenever scheduling is not permitted.

Regards.
--
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Messages in current thread:
use of preempt_count instead of in_atomic() at leds-gpio.c, Henrique de Moraes H ..., (Sun Mar 16, 11:43 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, David Brownell, (Sun Mar 16, 12:46 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Tue Mar 18, 12:14 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, David Brownell, (Tue Mar 18, 12:06 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Tue Mar 18, 1:07 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Henrique de Moraes H ..., (Thu Mar 20, 3:56 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Thu Mar 20, 4:47 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Henrique de Moraes H ..., (Thu Mar 20, 5:36 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Richard Purdie, (Thu Mar 20, 5:56 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Thu Mar 20, 6:08 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Alan Stern, (Thu Mar 20, 6:31 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Michael Buesch, (Thu Mar 20, 6:36 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Henrique de Moraes H ..., (Thu Mar 20, 7:10 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Thu Mar 20, 7:27 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Alan Stern, (Thu Mar 20, 8:07 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Thu Mar 20, 8:17 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Stefan Richter, (Fri Mar 21, 2:21 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Stefan Richter, (Fri Mar 21, 2:27 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Jean Delvare, (Fri Mar 21, 2:53 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Henrique de Moraes H ..., (Fri Mar 21, 5:37 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Stefan Richter, (Fri Mar 21, 6:16 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Heiko Carstens, (Fri Mar 21, 6:47 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Tetsuo Handa, (Fri Mar 21, 8:11 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Greg KH, (Fri Mar 21, 9:54 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Stefan Richter, (Fri Mar 21, 9:54 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Stefan Richter, (Fri Mar 21, 10:02 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, David Brownell, (Fri Mar 21, 10:04 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Fri Mar 21, 10:37 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Alan Stern, (Fri Mar 21, 11:05 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Fri Mar 21, 12:59 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Michael Buesch, (Fri Mar 21, 1:16 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Michael Buesch, (Fri Mar 21, 1:20 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Stefan Richter, (Sat Mar 22, 4:29 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Tetsuo Handa, (Sat Mar 22, 10:53 pm)
Re: use of preempt_count instead of in_atomic() at leds-gp ..., Jonathan Corbet, (Mon Mar 24, 12:34 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Andrew Morton, (Mon Mar 24, 12:42 pm)
Re: use of preempt_count instead of in_atomic() at leds-gp ..., Jonathan Corbet, (Mon Mar 24, 12:53 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Junio C Hamano, (Tue Mar 25, 1:52 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Jean Delvare, (Tue Mar 25, 3:39 am)
Re: use of preempt_count instead of in_atomic() at leds-gp ..., Jonathan Corbet, (Tue Mar 25, 6:44 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, David Brownell, (Tue Mar 25, 4:20 pm)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Alan Stern, (Wed Mar 26, 7:28 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Henrique de Moraes H ..., (Wed Mar 26, 9:17 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, Richard Purdie, (Wed Mar 26, 9:46 am)
Re: use of preempt_count instead of in_atomic() at leds-gpio.c, David Brownell, (Thu Mar 27, 11:51 am)