-----Original Message----- From: Mandeep Sandhu [mailto:mandeepsandhu.chd@gmail.com] Sent: Thursday, April 09, 2015 5:21 PM To: Jeff Haran Cc: kernelnewbies Subject: Re: maybe dumb question about RCU
256 If you are going to be fetching multiple fields from the 257 RCU-protected structure, using the local variable is of 258 course preferred. Repeated rcu_dereference() calls look 259 ugly and incur unnecessary overhead on Alpha CPUs.
"look ugly and incur unnecessary overhead on Alpha CPUs" is a long way from "can return different pointer values", which is what it should say.
I agree, that statement is not only misleading, but incorrect too. Maybe we can delete it and update it with a "Note:" about your findings? How about sending a doc patch for it?
I can try. Posting patches unmolested through my employer's Outlook email servers has been fraught with frustration in the past when I've tried it. 8^( But it would be nice to hear from an RCU expert whether this is a feature or a bug. I suspect the former, I really can't see how it could work otherwise, but what do I know? Jeff Haran