Sorry, sent HTML mail by mistake, so resending :-/ On Sat, Sep 20, 2008 at 10:24 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > +#define MAX3100_MAJOR 204 > > Allocating a new major is a Big Deal. It involves getting the major > registered by contacting device@xxxxxxxxxxx > > It's better to dynamically allocate it - let udev handle it. > I looked at other serial driver as an example and checked devices.txt: if I don't get it wrong major 204 should be already reserved for serial port. Anyway I choose a minor number already allocated by mistake (did not see the "...") and will correct that. Is this ok or I *have to* move to dynamic major (it's a bit a nuisance since max3100 is used in embedded system where udev is not always used)? > `struct max3100_port' is sufficient, and would be more typical. > > > + struct uart_port port; > > + struct spi_device *spi; > > + > > + int cts:1; /* last CTS received for flow ctrl */ > > + int tx_empty:1; /* last TX empty bit */ > > These two bits will share a word and hence locking is needed to prevent > modifications to one from trashing modifications to the other on SMP. > > That's OK, but it would be best to document that locking right here, and > to check that it is adhered to. > I did not realize this until you explained me. I'm not sure if actual packing of bit-fields is implementation dependent but I think so. If this is right I guess it's better to avoid bit-fields in structs that can be accessed concurrently (or otherwise I have to lock the entire struct). So, should I avoid bit-fields altogether? I will correct the patch and resend. Thanks, -- Christian Pellegrin, see http://www.evolware.org/chri/ "Real Programmers don't play tennis, or any other sport which requires you to change clothes. Mountain climbing is OK, and Real Programmers wear their climbing boots to work in case a mountain should suddenly spring up in the middle of the computer room." -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
