[PATCH 7/8] erofs: adapt folios for z_erofs_readahead()

[Chao Yu]

On 2023/8/17 16:28, Gao Xiang wrote:
> It's a straight-forward conversion except that readahead_folio()
> will do folio_put() in advance but it doesn't matter since folios
> are still locked.
> 
> As before, since file-backed folios (pages for now) are locked, so
> we could temporarily use folio->private as an internal counter to
> indicate split parts of each folio for the corresponding pclusters
> to decompress.
> 
> When such counter becomes zero, the folio will be finally unlocked
> (see compress.h and z_erofs_onlinepage_endio()).
> 
> Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>

Reviewed-by: Chao Yu <chao at kernel.org>

Thanks,