diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2020-01-14 18:25:32 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-23 08:22:35 +0100 |
| commit | f3cc7058d6f50b5a76a836d035c6e7695be45504 (patch) | |
| tree | d3aecf9d4f4fdccbbb380519b27d758632ad6ac9 | |
| parent | 829fbd1ddf9682218bfeefcad92ed8e7d99dfe0e (diff) | |
staging: comedi: ni_routes: allow partial routing information
commit 9fea3a40f6b07de977a2783270c8c3bc82544d45 upstream.
This patch fixes a regression on setting up asynchronous commands to use
external trigger sources when board-specific routing information is
missing.
`ni_find_device_routes()` (called via `ni_assign_device_routes()`) finds
the table of register values for the device family and the set of valid
routes for the specific board. If both are found,
`tables->route_values` is set to point to the table of register values
for the device family and `tables->valid_routes` is set to point to the
list of valid routes for the specific board. If either is not found,
both `tables->route_values` and `tables->valid_routes` are left set at
their initial null values (initialized by `ni_assign_device_routes()`)
and the function returns `-ENODATA`.
Returning an error results in some routing functionality being disabled.
Unfortunately, leaving `table->route_values` set to `NULL` also breaks
the setting up of asynchronous commands that are configured to use
external trigger sources. Calls to `ni_check_trigger_arg()` or
`ni_check_trigger_arg_roffs()` while checking the asynchronous command
set-up would result in a null pointer dereference if
`table->route_values` is `NULL`. The null pointer dereference is fixed
in another patch, but it now results in failure to set up the
asynchronous command. That is a regression from the behavior prior to
commit 347e244884c3 ("staging: comedi: tio: implement global tio/ctr
routing") and commit 56d0b826d39f ("staging: comedi: ni_mio_common:
implement new routing for TRIG_EXT").
Change `ni_find_device_routes()` to set `tables->route_values` and/or
`tables->valid_routes` to valid information even if the other one can
only be set to `NULL` due to missing information. The function will
still return an error in that case. This should result in
`tables->valid_routes` being valid for all currently supported device
families even if the board-specific routing information is missing.
That should be enough to fix the regression on setting up asynchronous
commands to use external triggers for boards with missing routing
information.
Fixes: 347e244884c3 ("staging: comedi: tio: implement global tio/ctr routing")
Fixes: 56d0b826d39f ("staging: comedi: ni_mio_common: implement new routing for TRIG_EXT").
Cc: <stable@vger.kernel.org> # 4.20+
Cc: Spencer E. Olson <olsonse@umich.edu>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20200114182532.132058-3-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/comedi/drivers/ni_routes.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/drivers/staging/comedi/drivers/ni_routes.c b/drivers/staging/comedi/drivers/ni_routes.c index fe96c4ee90b3..88beb0d6c42b 100644 --- a/drivers/staging/comedi/drivers/ni_routes.c +++ b/drivers/staging/comedi/drivers/ni_routes.c @@ -74,9 +74,6 @@ static int ni_find_device_routes(const char *device_family, } } - if (!rv) - return -ENODATA; - /* Second, find the set of routes valid for this device. */ for (i = 0; ni_device_routes_list[i]; ++i) { if (memcmp(ni_device_routes_list[i]->device, board_name, @@ -86,12 +83,12 @@ static int ni_find_device_routes(const char *device_family, } } - if (!dr) - return -ENODATA; - tables->route_values = rv; tables->valid_routes = dr; + if (!rv || !dr) + return -ENODATA; + return 0; } |