Re: [PATCH/RFC] allow mapping from block-device-file to sysfsentry.

From: Arjan van de Ven
Date: Tue Aug 07 2007 - 02:38:50 EST


On Tue, 2007-08-07 at 16:07 +1000, Neil Brown wrote:
> Suppose that in a program I have an open file descriptor for a device,
> and I want to find the /sys/block information for this device.
> There is currently no direct way to do this. I need to read
> /sys/block/*/dev, /sys/block/*/*/dev
> and match major/minor numbers with the result from fstat.
>
> I would like a more direct mechanism.
>
> The following patch is a proposal for such a mechanism.
>
> It provides an 'ioctl' which returns then 'name' of the device, as
> generated by bdevname. This is the same name that is used to create
> entries in sysfs.
> For a partition of a device, it returns 'device/partition'.


how about returning the entire path relative to the start of sysfs? That
way, if things move or something you're tolerant against that....

(I'd not be against making this a generic IOCTL for every device, a
SYSFSLOCATION kind of ioctl... it's by no means block specific...)


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