[PATCH v4 017/145] smb: smbdirect: introduce smbdirect_connection_reassembly_{append, first}_recv_io()

[Stefan Metzmacher]

These are basically copies of enqueue_reassembly() and
[_]get_first_reassembly() of both client and server. The only difference
is that enqueue_reassembly() of the server does not have:
sc->statistics.enqueue_reassembly_queue++

Also smbdirect_connection_reassembly_first_recv_io() makes use of
list_first_entry_or_null() in order to simplify the code.

In the next commits they will replace the existing functions.

Cc: Steve French <smfrench at gmail.com>
Cc: Tom Talpey <tom at talpey.com>
Cc: Long Li <longli at microsoft.com>
Cc: Namjae Jeon <linkinjeon at kernel.org>
Cc: linux-cifs at vger.kernel.org
Cc: samba-technical at lists.samba.org
Signed-off-by: Stefan Metzmacher <metze at samba.org>
Signed-off-by: Steve French <stfrench at microsoft.com>
---
 .../common/smbdirect/smbdirect_connection.c   | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/fs/smb/common/smbdirect/smbdirect_connection.c b/fs/smb/common/smbdirect/smbdirect_connection.c
index db807fb9e3db..aa554527f993 100644
--- a/fs/smb/common/smbdirect/smbdirect_connection.c
+++ b/fs/smb/common/smbdirect/smbdirect_connection.c
@@ -52,3 +52,43 @@ static void smbdirect_connection_put_recv_io(struct smbdirect_recv_io *msg)
 
 	queue_work(sc->workqueue, &sc->recv_io.posted.refill_work);
 }
+
+__maybe_unused /* this is temporary while this file is included in others */
+static void smbdirect_connection_reassembly_append_recv_io(struct smbdirect_socket *sc,
+							   struct smbdirect_recv_io *msg,
+							   u32 data_length)
+{
+	unsigned long flags;
+
+	/*
+	 * The work should already/still be disabled
+	 */
+	disable_work(&msg->complex_work);
+
+	spin_lock_irqsave(&sc->recv_io.reassembly.lock, flags);
+	list_add_tail(&msg->list, &sc->recv_io.reassembly.list);
+	sc->recv_io.reassembly.queue_length++;
+	/*
+	 * Make sure reassembly_data_length is updated after list and
+	 * reassembly_queue_length are updated. On the dequeue side
+	 * reassembly_data_length is checked without a lock to determine
+	 * if reassembly_queue_length and list is up to date
+	 */
+	virt_wmb();
+	sc->recv_io.reassembly.data_length += data_length;
+	spin_unlock_irqrestore(&sc->recv_io.reassembly.lock, flags);
+	sc->statistics.enqueue_reassembly_queue++;
+}
+
+__maybe_unused /* this is temporary while this file is included in others */
+static struct smbdirect_recv_io *
+smbdirect_connection_reassembly_first_recv_io(struct smbdirect_socket *sc)
+{
+	struct smbdirect_recv_io *msg;
+
+	msg = list_first_entry_or_null(&sc->recv_io.reassembly.list,
+				       struct smbdirect_recv_io,
+				       list);
+
+	return msg;
+}
-- 
2.43.0