Re: using long instead of atomic_t when only set/read is required (was Re: [Bug 10030] Suspend doesn't work when SD card is inserted)

Alan Stern
2008-02-25T14:46:21Z

On Mon, 25 Feb 2008, Pavel Machek wrote:

> Hi!
>
> Alan thinks that `subj` is correct...

More precisely, reads and writes of pointers are always atomic. That
is, if a write and a read occur concurrently, it is guaranteed that the
read will obtain either the old or the new value of the pointer, never
a mish-mash of the two. If this were not so then RCU wouldn't work.

> I guess it only works as long as longs are aligned? Should it be
> written down to atomic_ops.txt?

Forget it, I'm going to withdraw the entire thing. The whole approach
is wrong. More details in a new email thread, to follow soon.

Alan Stern