![]() | |||||||||||||
Messages in this thread |
Paul E. McKenney wrote: >On Sun, Oct 23, 2005 at 11:42:17PM -0500, Matt Domsch wrote: > > >>On Sun, Oct 23, 2005 at 07:19:32PM -0700, Paul E. McKenney wrote: >> >> >>>My guess is that this read-side critical section can be invoked from and >>>SMI, and that SMIs can occur even if interrupts are disabled. If my guess >>>is wrong, please enlighten me. And feel free to ignore the next few >>>paragraphs in that case, along with a number of my suggested changes, >>>since they all depend critically on my guess being correct. >>> >>> >>Paul, it took me a bit to figure this out too, but Corey uses the TLA >>"SMI" to mean "Systems Management Interface", not "Systems Management >>Interrupt". From Documentation/IPMI.txt: >> >>ipmi_msghandler - This is the central piece of software for the IPMI >>system. It handles all messages, message timing, and responses. The >>IPMI users tie into this, and the IPMI physical interfaces (called >>System Management Interfaces, or SMIs) also tie in here. >> >> >>There are at least 4 basic types of physical hardware interfaces (BT, >>SMIC, KCS, and I2C), which may (or more often, may not) have their own >>hardware interrupt lines, but these are normal interrupts, not >>CPU-magic "systems management interrupts". So I think this isn't a >>problem. >> >> > >OK, thank you for the tutorial on the "other SMI"! > > Yeah, I've really misnamed this, unfortunately. Too many TLAs. >The comments about turning synchronize_rcu() into synchronize_sched() >and rcu_read_lock() into preempt_disable() do not apply, please ignore. > >However, I still do not understand how using RCU on cmd_rcvrs helps, >given that all of the accesses that I could see were already protected >by cmd_rcvrs_lock. > >Any further enlightenment available? > > The calls in handle_ipmb_get_msg_cmd and handle_lan_get_msg_cmd don't need spinlock protection, just an RCU read lock. Kind of the point of the RCU list. Thanks for spotting this. Thanks, -Corey - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
| Last update: 2005-10-24 12:55 [from the cache] ©2003-2008 | |||||||||||||