Re: [RFC] raise the maximum number of usb-serial devices to 512

[Dave Jones <davej@redhat.com>]

On Mon, Jun 03, 2013 at 07:49:59PM -0700, Greg Kroah-Hartman wrote:
 > On Mon, May 27, 2013 at 02:28:51PM +0200, Bjørn Mork wrote:
 > > But, IMHO, a nicer approach would be to make the allocation completely
 > > dynamic, using e.g. the idr subsystem. Static tables are always feel
 > > like straight jackets to me, no matter how big they are :)
 > 
 > You are right, I didn't change the code to use idr (it predates idr by
 > about a decade or so), because I thought we needed the "rage" logic that
 > the usb-serial minor reservation does.

Rage logic sounds like my kinda code.


 > +static int get_free_port(struct usb_serial_port *port)
 >  {
 > -	unsigned int i, j;
 > -	int good_spot;
 > -
 > -	dev_dbg(&serial->interface->dev, "%s %d\n", __func__, num_ports);
 > +	int i;
 >  
 > -	*minor = 0;
 >  	mutex_lock(&table_lock);
 > -	for (i = 0; i < SERIAL_TTY_MINORS; ++i) {
 > -		if (serial_table[i])
 > -			continue;
 > +	i = idr_alloc(&serial_minors, port, 0, 0, GFP_KERNEL);
 > +	if (i < 0)
 > +		return -EEXIST;
 > +	port->number = i;
 > +	mutex_unlock(&table_lock);
 > +	return i;
 > +}

-EEXIST case misses the mutex unlock.

	Dave