[PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Randy Dunlap]

From: Randy Dunlap <rdunlap@infradead.org>

drivers/vdpa/mlx5/ uses vhost_iotlb*() interfaces, so add a dependency
on VHOST to eliminate build errors.

ld: drivers/vdpa/mlx5/core/mr.o: in function `add_direct_chain':
mr.c:(.text+0x106): undefined reference to `vhost_iotlb_itree_first'
ld: mr.c:(.text+0x1cf): undefined reference to `vhost_iotlb_itree_next'
ld: mr.c:(.text+0x30d): undefined reference to `vhost_iotlb_itree_first'
ld: mr.c:(.text+0x3e8): undefined reference to `vhost_iotlb_itree_next'
ld: drivers/vdpa/mlx5/core/mr.o: in function `_mlx5_vdpa_create_mr':
mr.c:(.text+0x908): undefined reference to `vhost_iotlb_itree_first'
ld: mr.c:(.text+0x9e6): undefined reference to `vhost_iotlb_itree_next'
ld: drivers/vdpa/mlx5/core/mr.o: in function `mlx5_vdpa_handle_set_map':
mr.c:(.text+0xf1d): undefined reference to `vhost_iotlb_itree_first'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: Saeed Mahameed <saeedm@nvidia.com>
Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: netdev@vger.kernel.org
---
v2: change from select to depends on VHOST (Saeed)
v3: change to depends on VHOST_IOTLB (Jason)

 drivers/vdpa/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200917.orig/drivers/vdpa/Kconfig
+++ linux-next-20200917/drivers/vdpa/Kconfig
@@ -31,7 +31,7 @@ config IFCVF
 
 config MLX5_VDPA
 	bool "MLX5 VDPA support library for ConnectX devices"
-	depends on MLX5_CORE
+	depends on VHOST_IOTLB && MLX5_CORE
 	default n
 	help
 	  Support library for Mellanox VDPA drivers. Provides code that is

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Leon Romanovsky]

On Thu, Sep 17, 2020 at 07:35:03PM -0700, Randy Dunlap wrote:
> From: Randy Dunlap <rdunlap@infradead.org>
>
> drivers/vdpa/mlx5/ uses vhost_iotlb*() interfaces, so add a dependency
> on VHOST to eliminate build errors.
>
> ld: drivers/vdpa/mlx5/core/mr.o: in function `add_direct_chain':
> mr.c:(.text+0x106): undefined reference to `vhost_iotlb_itree_first'
> ld: mr.c:(.text+0x1cf): undefined reference to `vhost_iotlb_itree_next'
> ld: mr.c:(.text+0x30d): undefined reference to `vhost_iotlb_itree_first'
> ld: mr.c:(.text+0x3e8): undefined reference to `vhost_iotlb_itree_next'
> ld: drivers/vdpa/mlx5/core/mr.o: in function `_mlx5_vdpa_create_mr':
> mr.c:(.text+0x908): undefined reference to `vhost_iotlb_itree_first'
> ld: mr.c:(.text+0x9e6): undefined reference to `vhost_iotlb_itree_next'
> ld: drivers/vdpa/mlx5/core/mr.o: in function `mlx5_vdpa_handle_set_map':
> mr.c:(.text+0xf1d): undefined reference to `vhost_iotlb_itree_first'
>
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Cc: virtualization@lists.linux-foundation.org
> Cc: Saeed Mahameed <saeedm@nvidia.com>
> Cc: Leon Romanovsky <leonro@nvidia.com>
> Cc: netdev@vger.kernel.org
> ---
> v2: change from select to depends on VHOST (Saeed)
> v3: change to depends on VHOST_IOTLB (Jason)
>
>  drivers/vdpa/Kconfig |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> +++ linux-next-20200917/drivers/vdpa/Kconfig
> @@ -31,7 +31,7 @@ config IFCVF
>
>  config MLX5_VDPA
>  	bool "MLX5 VDPA support library for ConnectX devices"
> -	depends on MLX5_CORE
> +	depends on VHOST_IOTLB && MLX5_CORE
>  	default n

While we are here, can anyone who apply this patch delete the "default n" line?
It is by default "n".

Thanks

>  	help
>  	  Support library for Mellanox VDPA drivers. Provides code that is
>

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Michael S. Tsirkin]

On Fri, Sep 18, 2020 at 11:22:45AM +0300, Leon Romanovsky wrote:
> On Thu, Sep 17, 2020 at 07:35:03PM -0700, Randy Dunlap wrote:
> > From: Randy Dunlap <rdunlap@infradead.org>
> >
> > drivers/vdpa/mlx5/ uses vhost_iotlb*() interfaces, so add a dependency
> > on VHOST to eliminate build errors.
> >
> > ld: drivers/vdpa/mlx5/core/mr.o: in function `add_direct_chain':
> > mr.c:(.text+0x106): undefined reference to `vhost_iotlb_itree_first'
> > ld: mr.c:(.text+0x1cf): undefined reference to `vhost_iotlb_itree_next'
> > ld: mr.c:(.text+0x30d): undefined reference to `vhost_iotlb_itree_first'
> > ld: mr.c:(.text+0x3e8): undefined reference to `vhost_iotlb_itree_next'
> > ld: drivers/vdpa/mlx5/core/mr.o: in function `_mlx5_vdpa_create_mr':
> > mr.c:(.text+0x908): undefined reference to `vhost_iotlb_itree_first'
> > ld: mr.c:(.text+0x9e6): undefined reference to `vhost_iotlb_itree_next'
> > ld: drivers/vdpa/mlx5/core/mr.o: in function `mlx5_vdpa_handle_set_map':
> > mr.c:(.text+0xf1d): undefined reference to `vhost_iotlb_itree_first'
> >
> > Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> > Cc: "Michael S. Tsirkin" <mst@redhat.com>
> > Cc: Jason Wang <jasowang@redhat.com>
> > Cc: virtualization@lists.linux-foundation.org
> > Cc: Saeed Mahameed <saeedm@nvidia.com>
> > Cc: Leon Romanovsky <leonro@nvidia.com>
> > Cc: netdev@vger.kernel.org
> > ---
> > v2: change from select to depends on VHOST (Saeed)
> > v3: change to depends on VHOST_IOTLB (Jason)
> >
> >  drivers/vdpa/Kconfig |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> > +++ linux-next-20200917/drivers/vdpa/Kconfig
> > @@ -31,7 +31,7 @@ config IFCVF
> >
> >  config MLX5_VDPA
> >  	bool "MLX5 VDPA support library for ConnectX devices"
> > -	depends on MLX5_CORE
> > +	depends on VHOST_IOTLB && MLX5_CORE
> >  	default n
> 
> While we are here, can anyone who apply this patch delete the "default n" line?
> It is by default "n".
> 
> Thanks

Hmm other drivers select VHOST_IOTLB, why not do the same?


> >  	help
> >  	  Support library for Mellanox VDPA drivers. Provides code that is
> >

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Eli Cohen]

On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
> > > --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> > > +++ linux-next-20200917/drivers/vdpa/Kconfig
> > > @@ -31,7 +31,7 @@ config IFCVF
> > >
> > >  config MLX5_VDPA
> > >  	bool "MLX5 VDPA support library for ConnectX devices"
> > > -	depends on MLX5_CORE
> > > +	depends on VHOST_IOTLB && MLX5_CORE
> > >  	default n
> > 
> > While we are here, can anyone who apply this patch delete the "default n" line?
> > It is by default "n".

I can do that

> > 
> > Thanks
> 
> Hmm other drivers select VHOST_IOTLB, why not do the same?

I can't see another driver doing that. Perhaps I can set dependency on
VHOST which by itself depends on VHOST_IOTLB?
> 
> 
> > >  	help
> > >  	  Support library for Mellanox VDPA drivers. Provides code that is
> > >
> 

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Randy Dunlap]

On 9/24/20 3:24 AM, Eli Cohen wrote:
> On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
>>>> --- linux-next-20200917.orig/drivers/vdpa/Kconfig
>>>> +++ linux-next-20200917/drivers/vdpa/Kconfig
>>>> @@ -31,7 +31,7 @@ config IFCVF
>>>>
>>>>  config MLX5_VDPA
>>>>  	bool "MLX5 VDPA support library for ConnectX devices"
>>>> -	depends on MLX5_CORE
>>>> +	depends on VHOST_IOTLB && MLX5_CORE
>>>>  	default n
>>>
>>> While we are here, can anyone who apply this patch delete the "default n" line?
>>> It is by default "n".
> 
> I can do that
> 
>>>
>>> Thanks
>>
>> Hmm other drivers select VHOST_IOTLB, why not do the same?

v1 used select, but Saeed requested use of depends instead because
select can cause problems.

> I can't see another driver doing that. Perhaps I can set dependency on
> VHOST which by itself depends on VHOST_IOTLB?
>>
>>
>>>>  	help
>>>>  	  Support library for Mellanox VDPA drivers. Provides code that is
>>>>
>>


-- 
~Randy

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Michael S. Tsirkin]

On Thu, Sep 24, 2020 at 08:47:05AM -0700, Randy Dunlap wrote:
> On 9/24/20 3:24 AM, Eli Cohen wrote:
> > On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
> >>>> --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> >>>> +++ linux-next-20200917/drivers/vdpa/Kconfig
> >>>> @@ -31,7 +31,7 @@ config IFCVF
> >>>>
> >>>>  config MLX5_VDPA
> >>>>  	bool "MLX5 VDPA support library for ConnectX devices"
> >>>> -	depends on MLX5_CORE
> >>>> +	depends on VHOST_IOTLB && MLX5_CORE
> >>>>  	default n
> >>>
> >>> While we are here, can anyone who apply this patch delete the "default n" line?
> >>> It is by default "n".
> > 
> > I can do that
> > 
> >>>
> >>> Thanks
> >>
> >> Hmm other drivers select VHOST_IOTLB, why not do the same?
> 
> v1 used select, but Saeed requested use of depends instead because
> select can cause problems.
> 
> > I can't see another driver doing that. Perhaps I can set dependency on
> > VHOST which by itself depends on VHOST_IOTLB?
> >>
> >>
> >>>>  	help
> >>>>  	  Support library for Mellanox VDPA drivers. Provides code that is
> >>>>
> >>
> 

Saeed what kind of problems? It's used with select in other places,
isn't it?

> -- 
> ~Randy

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Leon Romanovsky]

On Thu, Sep 24, 2020 at 12:02:43PM -0400, Michael S. Tsirkin wrote:
> On Thu, Sep 24, 2020 at 08:47:05AM -0700, Randy Dunlap wrote:
> > On 9/24/20 3:24 AM, Eli Cohen wrote:
> > > On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
> > >>>> --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> > >>>> +++ linux-next-20200917/drivers/vdpa/Kconfig
> > >>>> @@ -31,7 +31,7 @@ config IFCVF
> > >>>>
> > >>>>  config MLX5_VDPA
> > >>>>  	bool "MLX5 VDPA support library for ConnectX devices"
> > >>>> -	depends on MLX5_CORE
> > >>>> +	depends on VHOST_IOTLB && MLX5_CORE
> > >>>>  	default n
> > >>>
> > >>> While we are here, can anyone who apply this patch delete the "default n" line?
> > >>> It is by default "n".
> > >
> > > I can do that
> > >
> > >>>
> > >>> Thanks
> > >>
> > >> Hmm other drivers select VHOST_IOTLB, why not do the same?
> >
> > v1 used select, but Saeed requested use of depends instead because
> > select can cause problems.
> >
> > > I can't see another driver doing that. Perhaps I can set dependency on
> > > VHOST which by itself depends on VHOST_IOTLB?
> > >>
> > >>
> > >>>>  	help
> > >>>>  	  Support library for Mellanox VDPA drivers. Provides code that is
> > >>>>
> > >>
> >
>
> Saeed what kind of problems? It's used with select in other places,
> isn't it?

IMHO, "depends" is much more explicit than "select".

Thanks

>
> > --
> > ~Randy
>

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Michael S. Tsirkin]

On Fri, Sep 25, 2020 at 10:20:05AM +0300, Leon Romanovsky wrote:
> On Thu, Sep 24, 2020 at 12:02:43PM -0400, Michael S. Tsirkin wrote:
> > On Thu, Sep 24, 2020 at 08:47:05AM -0700, Randy Dunlap wrote:
> > > On 9/24/20 3:24 AM, Eli Cohen wrote:
> > > > On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
> > > >>>> --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> > > >>>> +++ linux-next-20200917/drivers/vdpa/Kconfig
> > > >>>> @@ -31,7 +31,7 @@ config IFCVF
> > > >>>>
> > > >>>>  config MLX5_VDPA
> > > >>>>  	bool "MLX5 VDPA support library for ConnectX devices"
> > > >>>> -	depends on MLX5_CORE
> > > >>>> +	depends on VHOST_IOTLB && MLX5_CORE
> > > >>>>  	default n
> > > >>>
> > > >>> While we are here, can anyone who apply this patch delete the "default n" line?
> > > >>> It is by default "n".
> > > >
> > > > I can do that
> > > >
> > > >>>
> > > >>> Thanks
> > > >>
> > > >> Hmm other drivers select VHOST_IOTLB, why not do the same?
> > >
> > > v1 used select, but Saeed requested use of depends instead because
> > > select can cause problems.
> > >
> > > > I can't see another driver doing that. Perhaps I can set dependency on
> > > > VHOST which by itself depends on VHOST_IOTLB?
> > > >>
> > > >>
> > > >>>>  	help
> > > >>>>  	  Support library for Mellanox VDPA drivers. Provides code that is
> > > >>>>
> > > >>
> > >
> >
> > Saeed what kind of problems? It's used with select in other places,
> > isn't it?
> 
> IMHO, "depends" is much more explicit than "select".
> 
> Thanks

This is now how VHOST_IOTLB has been designed though.
If you want to change VHOST_IOTLB to depends I think
we should do it consistently all over.


config VHOST_IOTLB
        tristate
        help
          Generic IOTLB implementation for vhost and vringh.
          This option is selected by any driver which needs to support
          an IOMMU in software.


> >
> > > --
> > > ~Randy
> >

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Michael S. Tsirkin]

On Thu, Sep 24, 2020 at 01:24:13PM +0300, Eli Cohen wrote:
> On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
> > > > --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> > > > +++ linux-next-20200917/drivers/vdpa/Kconfig
> > > > @@ -31,7 +31,7 @@ config IFCVF
> > > >
> > > >  config MLX5_VDPA
> > > >  	bool "MLX5 VDPA support library for ConnectX devices"
> > > > -	depends on MLX5_CORE
> > > > +	depends on VHOST_IOTLB && MLX5_CORE
> > > >  	default n
> > > 
> > > While we are here, can anyone who apply this patch delete the "default n" line?
> > > It is by default "n".
> 
> I can do that
> 
> > > 
> > > Thanks
> > 
> > Hmm other drivers select VHOST_IOTLB, why not do the same?
> 
> I can't see another driver doing that.

Well grep VHOST_IOTLB and you will see some examples.

> Perhaps I can set dependency on
> VHOST which by itself depends on VHOST_IOTLB?

VHOST is processing virtio in the kernel. You don't really need that
for mlx, do you?

> > 
> > 
> > > >  	help
> > > >  	  Support library for Mellanox VDPA drivers. Provides code that is
> > > >
> > 

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Jason Wang]

On 2020/9/25 下午6:19, Michael S. Tsirkin wrote:
> On Fri, Sep 25, 2020 at 10:20:05AM +0300, Leon Romanovsky wrote:
>> On Thu, Sep 24, 2020 at 12:02:43PM -0400, Michael S. Tsirkin wrote:
>>> On Thu, Sep 24, 2020 at 08:47:05AM -0700, Randy Dunlap wrote:
>>>> On 9/24/20 3:24 AM, Eli Cohen wrote:
>>>>> On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
>>>>>>>> --- linux-next-20200917.orig/drivers/vdpa/Kconfig
>>>>>>>> +++ linux-next-20200917/drivers/vdpa/Kconfig
>>>>>>>> @@ -31,7 +31,7 @@ config IFCVF
>>>>>>>>
>>>>>>>>   config MLX5_VDPA
>>>>>>>>   	bool "MLX5 VDPA support library for ConnectX devices"
>>>>>>>> -	depends on MLX5_CORE
>>>>>>>> +	depends on VHOST_IOTLB && MLX5_CORE
>>>>>>>>   	default n
>>>>>>> While we are here, can anyone who apply this patch delete the "default n" line?
>>>>>>> It is by default "n".
>>>>> I can do that
>>>>>
>>>>>>> Thanks
>>>>>> Hmm other drivers select VHOST_IOTLB, why not do the same?
>>>> v1 used select, but Saeed requested use of depends instead because
>>>> select can cause problems.
>>>>
>>>>> I can't see another driver doing that. Perhaps I can set dependency on
>>>>> VHOST which by itself depends on VHOST_IOTLB?
>>>>>>
>>>>>>>>   	help
>>>>>>>>   	  Support library for Mellanox VDPA drivers. Provides code that is
>>>>>>>>
>>> Saeed what kind of problems? It's used with select in other places,
>>> isn't it?
>> IMHO, "depends" is much more explicit than "select".
>>
>> Thanks
> This is now how VHOST_IOTLB has been designed though.
> If you want to change VHOST_IOTLB to depends I think
> we should do it consistently all over.
>
>
> config VHOST_IOTLB
>          tristate
>          help
>            Generic IOTLB implementation for vhost and vringh.
>            This option is selected by any driver which needs to support
>            an IOMMU in software.


Yes, since there's no prompt for VHOST_IOTLB which means, if there's no 
other symbol that select VHOST_IOTLB, you can't enable MLX5 at all.

See kconfig-language.rst:


     In general use select only for non-visible symbols
     (no prompts anywhere) and for symbols with no dependencies.
     That will limit the usefulness but on the other hand avoid
     the illegal configurations all over.

Thanks


>
>
>>>> --
>>>> ~Randy

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Leon Romanovsky]

On Fri, Sep 25, 2020 at 07:29:24PM +0800, Jason Wang wrote:
>
> On 2020/9/25 下午6:19, Michael S. Tsirkin wrote:
> > On Fri, Sep 25, 2020 at 10:20:05AM +0300, Leon Romanovsky wrote:
> > > On Thu, Sep 24, 2020 at 12:02:43PM -0400, Michael S. Tsirkin wrote:
> > > > On Thu, Sep 24, 2020 at 08:47:05AM -0700, Randy Dunlap wrote:
> > > > > On 9/24/20 3:24 AM, Eli Cohen wrote:
> > > > > > On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
> > > > > > > > > --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> > > > > > > > > +++ linux-next-20200917/drivers/vdpa/Kconfig
> > > > > > > > > @@ -31,7 +31,7 @@ config IFCVF
> > > > > > > > >
> > > > > > > > >   config MLX5_VDPA
> > > > > > > > >   	bool "MLX5 VDPA support library for ConnectX devices"
> > > > > > > > > -	depends on MLX5_CORE
> > > > > > > > > +	depends on VHOST_IOTLB && MLX5_CORE
> > > > > > > > >   	default n
> > > > > > > > While we are here, can anyone who apply this patch delete the "default n" line?
> > > > > > > > It is by default "n".
> > > > > > I can do that
> > > > > >
> > > > > > > > Thanks
> > > > > > > Hmm other drivers select VHOST_IOTLB, why not do the same?
> > > > > v1 used select, but Saeed requested use of depends instead because
> > > > > select can cause problems.
> > > > >
> > > > > > I can't see another driver doing that. Perhaps I can set dependency on
> > > > > > VHOST which by itself depends on VHOST_IOTLB?
> > > > > > >
> > > > > > > > >   	help
> > > > > > > > >   	  Support library for Mellanox VDPA drivers. Provides code that is
> > > > > > > > >
> > > > Saeed what kind of problems? It's used with select in other places,
> > > > isn't it?
> > > IMHO, "depends" is much more explicit than "select".
> > >
> > > Thanks
> > This is now how VHOST_IOTLB has been designed though.
> > If you want to change VHOST_IOTLB to depends I think
> > we should do it consistently all over.
> >
> >
> > config VHOST_IOTLB
> >          tristate
> >          help
> >            Generic IOTLB implementation for vhost and vringh.
> >            This option is selected by any driver which needs to support
> >            an IOMMU in software.
>
>
> Yes, since there's no prompt for VHOST_IOTLB which means, if there's no
> other symbol that select VHOST_IOTLB, you can't enable MLX5 at all.
>
> See kconfig-language.rst:
>
>
>     In general use select only for non-visible symbols
>     (no prompts anywhere) and for symbols with no dependencies.
>     That will limit the usefulness but on the other hand avoid
>     the illegal configurations all over.

Thanks, I wasn't aware of this clarification.

>
> Thanks
>
>
> >
> >
> > > > > --
> > > > > ~Randy
>

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Eli Cohen]

On Fri, Sep 25, 2020 at 06:20:45AM -0400, Michael S. Tsirkin wrote:
> > > 
> > > Hmm other drivers select VHOST_IOTLB, why not do the same?
> > 
> > I can't see another driver doing that.
> 
> Well grep VHOST_IOTLB and you will see some examples.

$ git grep -wn VHOST_IOTLB
drivers/vhost/Kconfig:2:config VHOST_IOTLB
drivers/vhost/Kconfig:11:       select VHOST_IOTLB
drivers/vhost/Kconfig:18:       select VHOST_IOTLB

What am I missing here?

> > Perhaps I can set dependency on
> > VHOST which by itself depends on VHOST_IOTLB?
> 
> VHOST is processing virtio in the kernel. You don't really need that
> for mlx, do you?
> 
> > > 
> > > 
> > > > >  	help
> > > > >  	  Support library for Mellanox VDPA drivers. Provides code that is
> > > > >
> > > 
> 

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Michael S. Tsirkin]

On Tue, Sep 29, 2020 at 09:01:42AM +0300, Eli Cohen wrote:
> On Fri, Sep 25, 2020 at 06:20:45AM -0400, Michael S. Tsirkin wrote:
> > > > 
> > > > Hmm other drivers select VHOST_IOTLB, why not do the same?
> > > 
> > > I can't see another driver doing that.
> > 
> > Well grep VHOST_IOTLB and you will see some examples.
> 
> $ git grep -wn VHOST_IOTLB
> drivers/vhost/Kconfig:2:config VHOST_IOTLB
> drivers/vhost/Kconfig:11:       select VHOST_IOTLB
> drivers/vhost/Kconfig:18:       select VHOST_IOTLB
> 
> What am I missing here?

Nothing, there's a select here as expected.

> > > Perhaps I can set dependency on
> > > VHOST which by itself depends on VHOST_IOTLB?
> > 
> > VHOST is processing virtio in the kernel. You don't really need that
> > for mlx, do you?
> > 
> > > > 
> > > > 
> > > > > >  	help
> > > > > >  	  Support library for Mellanox VDPA drivers. Provides code that is
> > > > > >
> > > > 
> > 

Re: [PATCH v3 -next] vdpa: mlx5: change Kconfig depends to fix build errors

[Michael S. Tsirkin]

On Thu, Sep 24, 2020 at 08:47:05AM -0700, Randy Dunlap wrote:
> On 9/24/20 3:24 AM, Eli Cohen wrote:
> > On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:
> >>>> --- linux-next-20200917.orig/drivers/vdpa/Kconfig
> >>>> +++ linux-next-20200917/drivers/vdpa/Kconfig
> >>>> @@ -31,7 +31,7 @@ config IFCVF
> >>>>
> >>>>  config MLX5_VDPA
> >>>>  	bool "MLX5 VDPA support library for ConnectX devices"
> >>>> -	depends on MLX5_CORE
> >>>> +	depends on VHOST_IOTLB && MLX5_CORE
> >>>>  	default n
> >>>
> >>> While we are here, can anyone who apply this patch delete the "default n" line?
> >>> It is by default "n".
> > 
> > I can do that
> > 
> >>>
> >>> Thanks
> >>
> >> Hmm other drivers select VHOST_IOTLB, why not do the same?
> 
> v1 used select, but Saeed requested use of depends instead because
> select can cause problems.

OK I went over the history. v1 selected VHOST, that as the issue I think.
A later version switched to VHOST_IOTLB, that is ok to select.

> > I can't see another driver doing that. Perhaps I can set dependency on
> > VHOST which by itself depends on VHOST_IOTLB?
> >>
> >>
> >>>>  	help
> >>>>  	  Support library for Mellanox VDPA drivers. Provides code that is
> >>>>
> >>
> 
> 
> -- 
> ~Randy