diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2015-10-12 17:21:27 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-13 10:29:48 -0700 |
| commit | a8ed75c0836ebc530f7fbf613bba75de3656b105 (patch) | |
| tree | e790c2e7376c4303a5e5a7b21deb0bb28520c6f0 /drivers/staging/comedi/comedi_fops.c | |
| parent | f84e27adfc4cb0c4aa97d830c43f8c82aca0547c (diff) | |
staging: comedi: return error on "read" if no command set up
The "read" file operation handler, `comedi_read()` returns an error for
pretty much any condition that prevents a "read" going ahead. One of
the conditions that prevents a "read" 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>
Diffstat (limited to 'drivers/staging/comedi/comedi_fops.c')
| -rw-r--r-- | drivers/staging/comedi/comedi_fops.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 88ba0b648805..190592ad0921 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2478,8 +2478,12 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes, } 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; @@ -2517,6 +2521,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes, break; } if (!s->busy) { + retval = -EINVAL; break; } if (s->busy != file) { |