8250 serial issues in 2.6.0-test9

Hi Russell,

I know you don't want to mess with the setserial problem I tripped over, and that's fine -- it's not a huge issue for me. While poking around at it, I noticed a couple other issues, which I'll just mention here in case anybody else wants to have a go at reworking this code.

Mostly this mail is just because I'm about to go on vacation, and didn't want all my pondering to be completely wasted :-)

Bjorn

serial8250_release_port():
When releasing an RSA port, it looks like serial8250_release_port() releases the wrong range ("start + offset" rather than "start") for the standard IO port region.

serial8250_request_port():
The error path ("ret < 0") leaks memory because request_region() kmallocs the new resource, but release_resource() doesn't free it.

serial8250_config_port():
Same leak as in serial8250_request_port().

serial8250_release_port()/serial8250_request_port():

	The problem I mentioned before -- _request_port() doesn't
	ioremap the region that was iounmapped by _release_port(),
	so "setserial /dev/ttyS0 port 0x3f8" causes an oops if
	ttyS0 is an MMIO uart:

	    uart_set_info()
	        serial8250_release_port()
	            iounmap(membase);
	            membase = NULL;
	            release_mem_region(mapbase, ...);
	        serial8250_request_port()
	            request_mem_region(mapbase, ...);
	        serial8250_startup()
	            serial_out()
	                port.iotype == IO_MEM, so
	                    writeb(value, membase);
	                        oops - null pointer dereference (membase == NULL)