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

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To: Alan Cox <alan@...>
Cc: Pavel Machek <pavel@...>, Paul E. McKenney <paulmck@...>, 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 - 1:11 pm

On Mon, 3 Mar 2008, Alan Cox wrote:


Miscommunication and lack of clarity.  CPU reads and writes _are_ 
guaranteed to be atomic.  What is not guaranteed is that the compiler 
will generate a single read or write instruction corresponding to a 
particular expression in C.

Consider a routine like the following:

	static task_struct *the_task;

	void store_task(void)
	{
		the_task = current;
	}

Is it possible to say whether readers examining "the_task" are 
guaranteed to see a coherent value?

Alan Stern		

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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 Stern, (Mon Mar 3, 1:11 pm)
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)