On Tue, Sep 02 2008, Thomas Petazzoni wrote: > Le Tue, 2 Sep 2008 10:13:54 +0200, > Jens Axboe <[EMAIL PROTECTED]> a écrit : > > > They do act in the same way now, but that is because > > end_that_request_last() automatically detects whether a request needs > > to be dequeued or not. > > Ok. > > > end_request() uses hard_cur_sectors, so it does indeed only act on the > > current segment of the request. end_*_request() act on the full > > request, hard_nr_sectors. > > Ok. Then, what's the difference between hard_cur_sectors and > current_nr_sectors, then ? > > Documentation/block/request.txt says: > > unsigned long hard_nr_sectors B Used to keep sector sane > unsigned long hard_nr_sectors B Used to keep nr_sectors sane > unsigned int current_nr_sectors DB Number of sectors in first > segment of request > unsigned int hard_cur_sectors B Used to keep current_nr_sectors > sane > > Which confuses me quite a lot.
The non hard_ variants can be modified by drivers (to increment a single sector, or whatever they want), whereas the hard_ variants are updated and maintain block layer internal state. -- Jens Axboe -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to [EMAIL PROTECTED] Please read the FAQ at http://kernelnewbies.org/FAQ
