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:

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On Thu, Sep 24, 2020 at 12:02:43PM -0400, Michael S. Tsirkin wrote:

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On Thu, Sep 24, 2020 at 08:47:05AM -0700, Randy Dunlap wrote:

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On 9/24/20 3:24 AM, Eli Cohen wrote:

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On Thu, Sep 24, 2020 at 05:30:55AM -0400, Michael S. Tsirkin wrote:

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--- 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

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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.

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I can't see another driver doing that. Perhaps I can set dependency on
VHOST which by itself depends on VHOST_IOTLB?

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  	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

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--
~Randy

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