Re: [RFC PATCH kernel] block: initialize block_device::bd_bdi for bdev_cache

[Christoph Hellwig]

On Thu, Jan 07, 2021 at 10:58:39AM +1100, Alexey Kardashevskiy wrote:
>> And AFAICT the root inode on
>> bdev superblock can get only to bdev_evict_inode() and bdev_free_inode().
>> Looking at bdev_evict_inode() the only thing that's used there from struct
>> block_device is really bd_bdi. bdev_free_inode() will also access
>> bdev->bd_stats and bdev->bd_meta_info. So we need to at least initialize
>> these to NULL as well.
>
> These are all NULL.
>
>> IMO the most logical place for all these
>> initializations is in bdev_alloc_inode()...
>
>
> This works. We can also check for NULL where it crashes. But I do not know 
> the code to make an informed decision...

The root inode is the special case, so I think moving the the initializers
for everything touched in ->evict_inode and ->free_inode to
bdev_alloc_inode makes most sense.

Alexey, do you want to respin or should I send a patch?