don't use ->bd_inode to access the block device size v3

[Jens Axboe]

On 10/18/21 4:11 AM, Christoph Hellwig wrote:
> Hi Jens,
> 
> various drivers currently poke directy at the block device inode, which
> is a bit of a mess.  This series cleans up the places that read the
> block device size to use the proper helpers.  I have separate patches
> for many of the other bd_inode uses, but this series is already big
> enough as-is,

This looks good to me. Followup question, as it's related - I've got a
hacky patch that caches the inode size in the bdev:

https://git.kernel.dk/cgit/linux-block/commit/?h=perf-wip&id=c754951eb7193258c35a574bd1ccccb7c4946ee4

so we don't have to dip into the inode itself for the fast path. While
it's obviously not something being proposed for inclusion right now, is
there a world in which we can make something like that work?

-- 
Jens Axboe