Hi Paul,
As I'm not so familiar with Linux kernel programming,
I found the following hunk in commit 7945ae1a06c5 difficult to grasp at first glance.
@@ -564,7 +584,7 @@ the other will wait until the first thread releases the lock.
38 exit(-1);
39 }
40 for (i = 0; i < 3; i++) {
- 41 ACCESS_ONCE(x)++;
+ 41 READ_ONCE(x)++;
42 poll(NULL, 0, 5);
43 }
44 if (pthread_mutex_unlock(pmlp) != 0) {
"The name READ_ONCE() seems to imply it is used for read access, but what
happens when it is used with a "++" operator?" was what I thought.
"ACCESS_ONCE(x)++" was already somewhat confusing for me.
Once you know its definition, you can see there is no problem. But it still
looks strange...
Don't kernel programmers feel strangeness in "READ_ONCE(x)++"?
This is just a random question. But if you could add some explanation of the
usage, that would be of help for novice programmers.
Thanks, Akira
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