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

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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>
This commit is contained in:
Ian Abbott 2015-11-18 17:55:09 +00:00 committed by Greg Kroah-Hartman
parent 35a7475dc8
commit 40d0e80e08
1 changed files with 8 additions and 3 deletions
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11
drivers/staging/comedi/comedi_fops.c
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@ -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;