Nishanth Menon <nm@xxxxxx> writes: > Rafael J. Wysocki had written, on 09/22/2010 07:03 PM, the following: >> [Trimming the CC list slightly.] > [...] > >> ... >> >> First, thanks for addressing the previous comments, things look much better >> now. In particular the documentation has been improved a lot in my view. > Thanks for the excellent reviews :) > > [...] > >>> + >>> +WARNING on OPP List Modification Vs Query operations: >>> +---------------------------------------------------- >>> +The OPP layer's query functions are expected to be used in multiple contexts >>> +(including calls from interrupt locked context) based on SoC framework >>> +implementation. Only OPP modification functions are guaranteed exclusivity by >>> +the OPP library. Exclusivity between query functions and modification functions >>> +should be handled by the users such as the SoC framework appropriately; else, >>> +there is a risk for the query functions to retrieve stale data. >> >> Well, this sounds like a good use case for RCU. > Kevin did point out rwlock but am I confusing with > http://lwn.net/Articles/364583/ > If I get the message right, rwlock is more or less on it's way out? RCU is different from the reader-writer locks that are on their way out. Let's think about RCU a little more and see if it might be worth using. As these APIs are infrequencly accessed, I'm thinking a single spinlock to protect the whole list from concurrent access/modification is sufficient. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
