Re: PROBLEM: 5.9.0-rc6 fails to compile due to 'redefinition of ‘dax_supported’'

[Robert Gadsdon]

On 9/20/20 7:25 PM, Stuart Little wrote:
> An update on this: I've done a bisect, with the following result.
>
> --- cut here ---
>
> e2ec5128254518cae320d5dc631b71b94160f663 is the first bad commit
> commit e2ec5128254518cae320d5dc631b71b94160f663
> Author: Jan Kara <jack@xxxxxxx>
> Date:   Sun Sep 20 08:54:42 2020 -0700
>
>      dm: Call proper helper to determine dax support
>      
>      DM was calling generic_fsdax_supported() to determine whether a device
>      referenced in the DM table supports DAX. However this is a helper for "leaf" device drivers so that
>      they don't have to duplicate common generic checks. High level code
>      should call dax_supported() helper which that calls into appropriate
>      helper for the particular device. This problem manifested itself as
>      kernel messages:
>      
>      dm-3: error: dax access failed (-95)
>      
>      when lvm2-testsuite run in cases where a DM device was stacked on top of
>      another DM device.
>      
>      Fixes: 7bf7eac8d648 ("dax: Arrange for dax_supported check to span multiple devices")
>      Cc: <stable@xxxxxxxxxxxxxxx>
>      Tested-by: Adrian Huang <ahuang12@xxxxxxxxxx>
>      Signed-off-by: Jan Kara <jack@xxxxxxx>
>      Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
>      Reported-by: kernel test robot <lkp@xxxxxxxxx>
>      Link: https://lore.kernel.org/r/160061715195.13131.5503173247632041975.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>      Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
>
>   drivers/dax/super.c   |  4 ++++
>   drivers/md/dm-table.c | 10 +++++++---
>   include/linux/dax.h   | 22 ++++++++++++++++++++--
>   3 files changed, 31 insertions(+), 5 deletions(-)
>
> --- end ---
Confirm that reverting this patch, 5.9-rc6 compiles OK ...

RG.