netfs: Make ops->init_rreq() optional

Make the ops->init_rreq() callback optional.  This isn't required for the
erofs changes I'm implementing to do on-demand read through fscache[1].
Further, ceph has an empty init_rreq method that can then be removed and
it's marked optional in the documentation.

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/20211227125444.21187-1-jefflexu@linux.alibaba.com/
Link: https://lore.kernel.org/r/20211228124419.103020-1-jefflexu@linux.alibaba.com
Link: https://lore.kernel.org/r/164251410387.3435901.2504600788262093313.stgit@warthog.procyon.org.uk/

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index b3d9459..c98e523 100644 (file)
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -297,10 +297,6 @@ out:
        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;
@@ -312,7 +308,6 @@ 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 6169659..501da99 100644 (file)
--- 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);
        }