From 40d0e80e08012ac99b187cbaaeb8aab92b71714d Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Wed, 18 Nov 2015 17:55:09 +0000 Subject: [PATCH] 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 Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_fops.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 4dd42890c641..2a2b5a06ed0e 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -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; -- 2.20.1