Hi, On Jan,Wednesday 14 2009, at 6:50 PM, Antti Kantee wrote:
On Wed Jan 14 2009 at 14:54:49 +0100, Adam Hamsik wrote:Because dm driver is not enabled in kernel yet, and it is installed asnew style module.I have written this small patch  to subr_devsw.c which enable auto-loading of pseudo-device drivers. In my patch I'm changing cdev_open/bdev_open routines to try to load module if they was not able to look up it.Good, we need this feature.I have also converted some of our well known pseudo-drivers to modulesso we can remove them from kernel., , . I don't have cgd or raidframe* setup but I will test itmore.Both take a few minutes to set up, so I don't think this is a very convincing excuse for lack of superficial testing.
I will do it when this patch will stabilise little bit. I have university
exams now so I don't have too much time.
There is one outstanding problem with loading device drivers which need argument in kernel config file e.g. pseudo-device cgd 4, I do not know how to pass this number to modcmd function which calls driver attach routine. With removing these drivers from kernel we can shrink it by 200k.You should fix cgd to not require a static configuration. Previouslyusers had to edit the kernel config file if they wanted more. Now theyhave to edit the source. Making something a module is not a goal for which we should sacrifice usability.
I will look at it for both ccd and cgd.
If you don't find a name, you still return success?
Where is the major/name loaded into the reverse lookup table in the first place? Or can't you load devices which weren't available when the kernel was config'd?
I need simple way how to translate device major number to device name. So I can load device module. Reverse lookup table is created from all majors
files in kernel by config.
What prevents an unload between the load and the lookup?
Nothing I'm not sure how to do that. Holding module_lock is during whole devsw_do_load is probably bad idea.
And just thinking out loud: would be cool if all the devices attached to devsw the same way (i.e. dynamically). Then there would be no separatehardconfig'd devices and dynamically attached ones, i.e. no "second class citizens". But that's not really related to your goal.
That would be great. We can probably add devsw's generated by config to some dynamic list from devsw_init.
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