Commit ff8973d9 authored Nov 12, 2008 by Phil Endecott Committed by Greg Kroah-Hartman Jan 07, 2009

USB: Remove restrictions on signal numbers in devio.c



Just over a year ago (!) I had this brief exchange with Alan Stern:

>> It seems that the signal that can be used with USBDEVFS_DISCSIGNAL and 
>> in usbdevfs_urb.signr is limited to the real-time signals SIGRTMIN to 
>> SIGRTMAX. What's the rationale for this restriction? I believe that a 
>> process can kill() itself with any signal number, can't it? I was 
>> planning to use SIGIO for usbdevfs_urb.signr and SIGTERM (uncaught) for 
>> USBDEVFS_DISCSIGNAL. I don't think I'll have a problem with using 
>> SIGRTMIN+n instead, but I'm curious to know if there's some subtle 
>> problem with the non-real-time signals that I should be aware of.
>
> I don't know of any reason for this restriction.

Since no-one else could think of a reason either, I offer the following 
patch which allows any signal to be used with USBDEVFS_DISCSIGNAL and 
usbdevfs_urb.signr.

Signed-off-by: Phil Endecott <usbpatch@chezphil.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent d767d888

drivers/usb/core/devio.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -981,9 +981,6 @@ static int proc_do_submiturb(struct dev_state ps, struct usbdevfs_urb uurb,
		return -EINVAL;
		if (!uurb->buffer)
		return -EINVAL;
		if (uurb->signr != 0 && (uurb->signr < SIGRTMIN \|\|
		uurb->signr > SIGRTMAX))
		return -EINVAL;
		if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL &&
		(uurb->endpoint & ~USB_ENDPOINT_DIR_MASK) == 0)) {
		ifnum = findintfep(ps->dev, uurb->endpoint);
		@@ -1401,8 +1398,6 @@ static int proc_disconnectsignal(struct dev_state ps, void __user arg)

		if (copy_from_user(&ds, arg, sizeof(ds)))
		return -EFAULT;
		if (ds.signr != 0 && (ds.signr < SIGRTMIN \|\| ds.signr > SIGRTMAX))
		return -EINVAL;
		ps->discsignr = ds.signr;
		ps->disccontext = ds.context;
		return 0;

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