Messages in this thread | | | Date | Thu, 16 Mar 2023 16:57:54 -0700 | Subject | Re: [PATCH 32/36] dmaengine: idxd: use const struct bus_type * | From | Fenghua Yu <> |
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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@intel.com> >>> Cc: Dave Jiang <dave.jiang@intel.com> >>> Cc: Vinod Koul <vkoul@kernel.org> >>> Cc: dmaengine@vger.kernel.org >>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >>> --- >>> 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@intel.com>
Thanks.
-Fenghua
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