[systemd-devel] udev_device_get_driver implementation

[Sayeed hyder]

 ll
/sys/devices/LNXSYSTM:00/device:00/ACPI0012:00/ndbus0/region1/pfn1.1/block/pmem1/
total 0
-r--r--r-- 1 root root 4096 Apr 19 09:38 alignment_offset
-rw-r--r-- 1 root root 4096 Apr 19 09:38 badblocks
lrwxrwxrwx 1 root root    0 Apr 19 09:38 bdi ->
../../../../../../../../virtual/bdi/259:3
-r--r--r-- 1 root root 4096 Apr 19 09:38 capability
drwxr-xr-x 2 root root    0 Apr 19 09:38 dax
-r--r--r-- 1 root root 4096 Apr 19 09:38 dev
lrwxrwxrwx 1 root root    0 Apr 19 09:38 device -> ../../../pfn1.1
-r--r--r-- 1 root root 4096 Apr 19 09:38 discard_alignment
-r--r--r-- 1 root root 4096 Apr 19 09:38 ext_range
drwxr-xr-x 2 root root    0 Apr 19 09:38 holders
-r--r--r-- 1 root root 4096 Apr 19 09:38 inflight
drwxr-xr-x 2 root root    0 Apr 19 09:38 power
drwxr-xr-x 2 root root    0 Apr 19 09:38 queue
-r--r--r-- 1 root root 4096 Apr 19 09:38 range
-r--r--r-- 1 root root 4096 Apr 19 09:38 removable
-r--r--r-- 1 root root 4096 Apr 19 09:38 ro
-r--r--r-- 1 root root 4096 Apr 19 09:38 size
drwxr-xr-x 2 root root    0 Apr 19 09:38 slaves
-r--r--r-- 1 root root 4096 Apr 19 09:38 stat
lrwxrwxrwx 1 root root    0 Apr 19 09:38 subsystem ->
../../../../../../../../../class/block
drwxr-xr-x 2 root root    0 Apr 19 09:38 trace
-rw-r--r-- 1 root root 4096 Apr 19 09:38 uevent


On Wed, Apr 24, 2019 at 11:53 AM Greg KH <gregkh at linuxfoundation.org> wrote:

> On Wed, Apr 24, 2019 at 10:10:08AM -0700, Sayeed hyder wrote:
> > Forgot to hit "reply all"
> >
> > On Wed, Apr 24, 2019 at 9:52 AM Sayeed hyder <csayeedh at gmail.com> wrote:
> >
> > > Hi Greg,
> > >
> > > Sure, this is what I get if I use the syspath from
> > > udev_device_get_syspath. As you can see, it is showing a symlink to a
> > > device, and there is no driver. If it helps, it is a DAX mounted
> persistent
> > > memory device.
> > >
> > > [image: image.png]
>
> Sorry, can't see images from a text email client :(
>
> Anyway, if this is a DAX device, are you _SURE_ you are dealing with a
> real device that is controlled by a driver, and not just a class device?
> Class devices do not have drivers.  How is the DAX device being exposed
> to userspace?
>
> Can you provide a text version of your image?  It's just sysfs, which is
> text...
>
> thanks,
>
> greg k-h
>
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