[Linux-cachefs] [PATCH] netfs: make ops->init_rreq() optional

[Jeff Layton]

On Tue, 2021-12-28 at 20:44 +0800, Jeffle Xu wrote:
> Hi, recently I'm developing erofs over fscache for implementing
> on-demand read, and erofs also implements an empty .init_rreq()
> callback[1].
> 
> [1] https://lkml.org/lkml/2021/12/27/224
> 
> If folks don't like this cleanup and prefer empty callback in upper fs,
> I'm also fine with that.
> ---
> There's already upper fs implementing empty .init_rreq() callback, and
> thus make it optional.
> 
> Signed-off-by: Jeffle Xu <jefflexu at linux.alibaba.com>
> ---
>  fs/ceph/addr.c         | 5 -----
>  fs/netfs/read_helper.c | 3 ++-
>  2 files changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> index e53c8541f5b2..c3537dfd8c04 100644
> --- a/fs/ceph/addr.c
> +++ b/fs/ceph/addr.c
> @@ -291,10 +291,6 @@ static void ceph_netfs_issue_op(struct netfs_read_subrequest *subreq)
>  	dout("%s: result %d\n", __func__, err);
>  }
>  
> -static void ceph_init_rreq(struct netfs_read_request *rreq, struct file *file)
> -{
> -}
> -
>  static void ceph_readahead_cleanup(struct address_space *mapping, void *priv)
>  {
>  	struct inode *inode = mapping->host;
> @@ -306,7 +302,6 @@ static void ceph_readahead_cleanup(struct address_space *mapping, void *priv)
>  }
>  
>  static const struct netfs_read_request_ops ceph_netfs_read_ops = {
> -	.init_rreq		= ceph_init_rreq,
>  	.is_cache_enabled	= ceph_is_cache_enabled,
>  	.begin_cache_operation	= ceph_begin_cache_operation,
>  	.issue_op		= ceph_netfs_issue_op,
> diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
> index 75c76cbb27cc..0befb0747c59 100644
> --- a/fs/netfs/read_helper.c
> +++ b/fs/netfs/read_helper.c
> @@ -55,7 +55,8 @@ static struct netfs_read_request *netfs_alloc_read_request(
>  		INIT_WORK(&rreq->work, netfs_rreq_work);
>  		refcount_set(&rreq->usage, 1);
>  		__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
> -		ops->init_rreq(rreq, file);
> +		if (ops->init_rreq)
> +			ops->init_rreq(rreq, file);
>  		netfs_stat(&netfs_n_rh_rreq);
>  	}
>  

This looks reasonable to me, since ceph doesn't need anything here
anyway.

Reviewed-by: Jeff Layton <jlayton at kernel.org>