>> On Tue, Apr 05 2016, Alan Stern wrote:
>>> Suppose one usb_function is carrying out an I/O operation while
>>> another one in the same config gets a Set-Interface request from the
>>> host.
> On Wed, 6 Apr 2016, Michal Nazarewicz wrote:
>> That cannot happen. A single instance of mass_storage cannot¹ be added
>> twice to the same configuration.
>>
>> ¹ To be more precise, not via configfs. A legacy gadget could do that,
>> but that would be a bug in that legacy driver, not f_mass_storage.
>> Moreover, no current legacy gadgets do that though so IMO this is an
>> academic discussion.
On Wed, Apr 06 2016, Alan Stern wrote:
> Okay. Then I suggest adding this explanation to the patch
> description.
Sounds good to me. I’d love someone to test this patch (I sadly have no
way of doing that at the moment) and with that I can resend it with
updated message.
> BTW, is configfs capable of adding a single instance twice in different
> configs? Or is that again something only legacy gadgets can do?
I don’t think so. I might be wrong though, but here’s configuration
from the original post:
mkdir functions/mass_storage.0
echo $file > functions/mass_storage.0/lun.0/file
ln -s functions/mass_storage.0 configs/c.1
ln -s functions/mass_storage.0 configs/c.2
This makes me suspect it’s not possible to link a function instance to
the same configuration twice, but now that I think about it, I’m not
quite sure what would happen if one did:
ln -s functions/mass_storage.0 configs/c.1/foo
ln -s functions/mass_storage.0 configs/c.1/bar
--
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»
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