Hi, I try to figure out locking strategy in FreeBSD and found 'ichsmb' device. There is a mutex which protects smb bus (ichsmb device). For example in ichsmb_readw() in sys/dev/ichsmb/ichsmb.c, the mutex is locked and a command is written to bus, then unbounded (but with timeout) sleep is done (mutex is unlocked during sleep). After sleep a word is read from bus and the mutex is unlocked.
1. If an use of the device IS NOT serialized by layers around then more calls to this function (or others) can be started or even done before the first one is finished. The mutex don't protect sms bus. 2. If an use of the device IS serialized by layers around then the mutex is useless. Moreover, I don't mension interrupt routine which uses the mutex and smb bus too. Am I right? Or did I miss something? Svata _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
