Hi, Greg,
On 3/16/23 03:16, Greg Kroah-Hartman wrote:
On Mon, Mar 13, 2023 at 12:07:27PM -0700, Fenghua Yu wrote:
Hi, Greg,
On 3/13/23 11:29, Greg Kroah-Hartman wrote:
In the functions unbind_store() and bind_store(), a struct bus_type *
should be a const one, as the driver core bus functions used by this
variable are expecting the pointer to be constant, and these functions
do not modify the pointer at all.
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Cc: dmaengine@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
Note, this is a patch that is a prepatory cleanup as part of a larger
series of patches that is working on resolving some old driver core
design mistakes. It will build and apply cleanly on top of 6.3-rc2 on
its own, but I'd prefer if I could take it through my driver-core tree
so that the driver core changes can be taken through there for 6.4-rc1.
drivers/dma/idxd/compat.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/idxd/compat.c b/drivers/dma/idxd/compat.c
index 3df21615f888..5fd38d1b9d28 100644
--- a/drivers/dma/idxd/compat.c
+++ b/drivers/dma/idxd/compat.c
@@ -16,7 +16,7 @@ extern void device_driver_detach(struct device *dev);
static ssize_t unbind_store(struct device_driver *drv, const char *buf, size_t count)
{
- struct bus_type *bus = drv->bus;
+ const struct bus_type *bus = drv->bus;
struct device *dev;
int rc = -ENODEV;
@@ -32,7 +32,7 @@ static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, 0200, NULL, unbind_store);
static ssize_t bind_store(struct device_driver *drv, const char *buf, size_t count)
{
- struct bus_type *bus = drv->bus;
+ const struct bus_type *bus = drv->bus;
struct device *dev;
struct device_driver *alt_drv = NULL;
int rc = -ENODEV;
After applying this patch, warning is reported:
drivers/dma/idxd/compat.c: In function ‘bind_store’:
drivers/dma/idxd/compat.c:47:47: warning: passing argument 2 of
‘driver_find’ discards ‘const’ qualifier from pointer target type
[-Wdiscarded-qualifiers]
47 | alt_drv = driver_find("idxd", bus);
| ^~~
In file included from ./include/linux/device.h:32,
from drivers/dma/idxd/compat.c:6:
./include/linux/device/driver.h:129:59: note: expected ‘struct bus_type *’
but argument is of type ‘const struct bus_type *’
129 | struct bus_type *bus);
| ~~~~~~~~~~~~~~~~~^~~
Should the "bus" parameter in driver_find() definition be changed to const
as well to avoid the warning?
Oops, yes, it needs an earlier patch in this series, sorry, I didn't
call that out properly in the notes section of the patch.
So I can just take this through my tree if that's ok.
Sure.
Acked-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Thanks.
-Fenghua
