[PATCH 27/27] direct-io: remove random prefetches

[David Sterba]

On Fri, Apr 15, 2022 at 06:52:58AM +0200, Christoph Hellwig wrote:
> Randomly poking into block device internals for manual prefetches isn't
> exactly a very maintainable thing to do.  And none of the performance
> criticil direct I/O implementations still use this library function
> anyway, so just drop it.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>

That the direct io function needed a valid bdev just for the prefetch
but nothing else was one of the reasons we had to keep the latest_bdev
in btrfs, so good riddance.

You may want to add the reference to the patch that added the prefetch,
65dd2aa90aa1 ("dio: optimize cache misses in the submission path") and
also remove #include <linux/prefetch.h> as there are no more uses of
prefetch in the file.

With that

Reviewed-by: David Sterba <dsterba at suse.com>