Re: [PATCH] bus: fsl-mc: add missing fsl_mc_bus_dpdbg_type declaration

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Hi Ioana,

Le 07/01/2026 à 06:30, Greg Kroah-Hartman a écrit :
> On Tue, Jan 06, 2026 at 07:54:21PM +0100, Christophe Leroy (CS GROUP) wrote:
>> Fix following sparse warning:
>>
>>    CHECK   drivers/bus/fsl-mc/fsl-mc-bus.c
>> drivers/bus/fsl-mc/fsl-mc-bus.c:435:26: warning: symbol 'fsl_mc_bus_dpdbg_type' was not declared. Should it be static?
>>
>> As it is exported it can't be static. So declare it in mc.h like
>> all other similar objects.
>>
>> Fixes: e70ba1b06c26 ("bus: fsl-mc: add the dpdbg device type")
>> Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
>> ---
>>   include/linux/fsl/mc.h | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/include/linux/fsl/mc.h b/include/linux/fsl/mc.h
>> index 897d6211c1635..28441a456bb48 100644
>> --- a/include/linux/fsl/mc.h
>> +++ b/include/linux/fsl/mc.h
>> @@ -451,6 +451,7 @@ extern const struct device_type fsl_mc_bus_dpdcei_type;
>>   extern const struct device_type fsl_mc_bus_dpaiop_type;
>>   extern const struct device_type fsl_mc_bus_dpci_type;
>>   extern const struct device_type fsl_mc_bus_dpdmai_type;
>> +extern const struct device_type fsl_mc_bus_dpdbg_type;
> 
> As it's obviously not used anywhere, this should not be the fix, please
> just mark it static and remove the EXPORT_SYMBOL_GPL() as well.

What's your opinion here as Maintainer of this driver, what should we do ?

Greg is right that it is nowhere used, and it is the same for several 
other types, the only difference being that they have a matching 
is_fsl_mc_bus_dp..() helper that hides the type, but not all helpers are 
used, and many of them are not used outside drivers/bus/fsl-mc/ which 
cannot be built as a module:

$ git grep is_fsl_mc_bus_
drivers/bus/fsl-mc/dprc-driver.c:       if (!is_fsl_mc_bus_dprc(mc_dev))
drivers/bus/fsl-mc/dprc-driver.c:       if (!is_fsl_mc_bus_dprc(mc_dev))
drivers/bus/fsl-mc/fsl-mc-allocator.c:  return is_fsl_mc_bus_dpbp(mc_dev) ||
drivers/bus/fsl-mc/fsl-mc-allocator.c: 
is_fsl_mc_bus_dpmcp(mc_dev) ||
drivers/bus/fsl-mc/fsl-mc-allocator.c:         is_fsl_mc_bus_dpcon(mc_dev);
drivers/bus/fsl-mc/fsl-mc-allocator.c:  if (is_fsl_mc_bus_dprc(mc_dev))
drivers/bus/fsl-mc/fsl-mc-allocator.c:  if (is_fsl_mc_bus_dprc(mc_dev))
drivers/bus/fsl-mc/fsl-mc-bus.c:        if (is_fsl_mc_bus_dprc(mc_dev) ||
drivers/bus/fsl-mc/fsl-mc-bus.c:            is_fsl_mc_bus_dpmcp(mc_dev)) {
drivers/bus/fsl-mc/fsl-mc-bus.c:        } else if 
(is_fsl_mc_bus_dpio(mc_dev)) {
drivers/bus/fsl-mc/fsl-mc-bus.c:                        if 
(is_fsl_mc_bus_dprc(mc_dev) &&
drivers/bus/fsl-mc/fsl-mc-bus.c:        if (is_fsl_mc_bus_dprc(mc_dev))
drivers/vfio/fsl-mc/vfio_fsl_mc.c:              int no_mmap = 
is_fsl_mc_bus_dprc(mc_dev);
drivers/vfio/fsl-mc/vfio_fsl_mc.c:      if 
(is_fsl_mc_bus_dprc(vdev->mc_dev)) {
drivers/vfio/fsl-mc/vfio_fsl_mc.c:              if 
(is_fsl_mc_bus_dprc(mc_dev))
drivers/vfio/fsl-mc/vfio_fsl_mc.c:      if (!is_fsl_mc_bus_dprc(mc_dev)) {
drivers/vfio/fsl-mc/vfio_fsl_mc.c:      if (!is_fsl_mc_bus_dprc(mc_dev))
drivers/vfio/fsl-mc/vfio_fsl_mc.c:      if (!is_fsl_mc_bus_dprc(mc_dev))
drivers/vfio/fsl-mc/vfio_fsl_mc.c:      if (is_fsl_mc_bus_dprc(mc_dev))
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dprc(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpni(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpio(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpsw(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpdmux(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpbp(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpcon(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpmcp(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpmac(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dprtc(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpseci(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpdcei(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpaiop(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpci(const 
struct fsl_mc_device *mc_dev)
include/linux/fsl/mc.h:static inline bool is_fsl_mc_bus_dpdmai(const 
struct fsl_mc_device *mc_dev)

And the only outside user is drivers/vfio/fsl-mc/vfio_fsl_mc.c which can 
be a module, but has been orphaned by commit af6605f87ca5 ("MAINTAINERS: 
Orphan vfio fsl-mc bus driver") and scheduled for removal by commit 
1b1d9ca13475 ("vfio/fsl-mc: Mark for removal")

Christophe