The `COMEDI_BUFINFO` ioctl is used to advance the current position in
the buffer and/or get the current buffer position. If no asynchronous
command is active (started via the file object that issued this ioctl),
this information is meaningless. Change it to return an error
(`-EINVAL`) in this case. Prior to this change, if a command was
started via a different file object, the ioctl returned `-EACCES`, but
now it will return `-EINVAL`, which is consistent with the current
behavior of the "read" and "write" file operation handlers.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/comedi_fops.c | 22 ++--------------------
1 file changed, 2 insertions(+), 20 deletions(-)
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index b7c9270..a9fabf7 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1123,24 +1123,8 @@ static int do_bufinfo_ioctl(struct comedi_device *dev,
async = s->async;
- if (!async) {
- dev_dbg(dev->class_dev,
- "subdevice does not have async capability\n");
- bi.buf_write_ptr = 0;
- bi.buf_read_ptr = 0;
- bi.buf_write_count = 0;
- bi.buf_read_count = 0;
- bi.bytes_read = 0;
- bi.bytes_written = 0;
- goto copyback;
- }
- if (!s->busy) {
- bi.bytes_read = 0;
- bi.bytes_written = 0;
- goto copyback_position;
- }
- if (s->busy != file)
- return -EACCES;
+ if (!async || s->busy != file)
+ return -EINVAL;
if (!(async->cmd.flags & CMDF_WRITE)) {
/* command was set up in "read" direction */
@@ -1165,7 +1149,6 @@ static int do_bufinfo_ioctl(struct comedi_device *dev,
bi.bytes_read = 0;
}
-copyback_position:
bi.buf_write_count = async->buf_write_count;
bi.buf_write_ptr = async->buf_write_ptr;
bi.buf_read_count = async->buf_read_count;
@@ -1174,7 +1157,6 @@ copyback_position:
if (become_nonbusy)
do_become_nonbusy(dev, s);
-copyback:
if (copy_to_user(arg, &bi, sizeof(bi)))
return -EFAULT;
--
2.7.0
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