Commit 40d0e80e authored Nov 18, 2015 by Ian Abbott Committed by Greg Kroah-Hartman Dec 21, 2015

staging: comedi: return error on "write" if no command set up

The "write" file operation handler, `comedi_write()` returns an error
for pretty much any condition that prevents a "write" going ahead. One
of the conditions that prevents a "write" going ahead is that no
asynchronous command has been set up, but that currently results in a
return value of 0 (unless COMEDI instructions are being processed or an
asynchronous command has been set up by a different file object).
Change it to return `-EINVAL` in this case.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 35a7475d

drivers/staging/comedi/comedi_fops.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -2331,9 +2331,12 @@ static ssize_t comedi_write(struct file file, const char __user buf,
		}

		async = s->async;

		if (!s->busy \|\| !nbytes)
		if (!nbytes)
		goto out;
		if (!s->busy) {
		retval = -EINVAL;
		goto out;
		}
		if (s->busy != file) {
		retval = -EACCES;
		goto out;
		@@ -2373,8 +2376,10 @@ static ssize_t comedi_write(struct file file, const char __user buf,
		retval = -ERESTARTSYS;
		break;
		}
		if (!s->busy)
		if (!s->busy) {
		retval = -EINVAL;
		break;
		}
		if (s->busy != file) {
		retval = -EACCES;
		break;