Re: [patch] Re: using long instead of atomic_t when only set/read is required

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To: Pavel Machek <pavel@...>
Cc: Alan Stern <stern@...>, Linus Torvalds <torvalds@...>, Andrew Morton <akpm@...>, Zdenek Kabelac <zdenek.kabelac@...>, <davem@...>, Rafael J. Wysocki <rjw@...>, Pierre Ossman <drzeus-mmc@...>, Kernel development list <linux-kernel@...>, pm list <linux-pm@...>
Date: Monday, March 3, 2008 - 11:48 am

> Ok, so linux actually atomicity of long?

No it doesn't. And even if it did you couldn't use long for this because
atomic_t also ensures the points operations complete are defined. You
might just about get away with volatile long * objects on x86 for simple
assignments but for anything else gcc can and will generate code to
update values whichever way it feels best - which includes turning

	long *x = a + b;

into

	*x = a;
	*x += b;

Alan
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Messages in current thread:
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Wed Feb 20, 6:15 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Wed Feb 20, 8:02 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Thu Feb 21, 12:38 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Thu Feb 21, 6:47 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Fri Feb 22, 9:30 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sat Feb 23, 4:16 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sat Feb 23, 8:19 pm)
Re: [linux-pm] [Bug 10030] Suspend doesn't work when SD card..., Rafael J. Wysocki, (Sun Feb 24, 10:00 am)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Mon Feb 25, 7:40 am)
Re: [patch] Re: using long instead of atomic_t when only set..., Alan Cox, (Mon Mar 3, 11:48 am)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sun Feb 24, 6:21 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Mon Feb 25, 7:41 am)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sun Feb 24, 9:51 am)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sun Feb 24, 4:09 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sun Feb 24, 9:33 am)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sun Feb 24, 4:25 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sun Feb 24, 4:56 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Sun Feb 24, 6:18 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Wed Feb 20, 6:41 pm)
Re: [Bug 10030] Suspend doesn't work when SD card is inserted, Rafael J. Wysocki, (Wed Feb 20, 4:58 pm)