[PATCH v2 013/127] smb: smbdirect: introduce smbdirect_connection_{get, put}_recv_io()

[Stefan Metzmacher]

These are basically copies of {get,put}_receive_buffer() in the client
and they are very similar to {get_free,put}_recvmsg() in the server.

The only difference to {get_free,put}_recvmsg() is the
updating of the sc->statistics.*.

In addition smbdirect_connection_get_recv_io() uses
list_first_entry_or_null() in order to simplify the code.

And smbdirect_connection_put_recv_io() uses msg->socket instead
of an explicit argument.

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   | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/fs/smb/common/smbdirect/smbdirect_connection.c b/fs/smb/common/smbdirect/smbdirect_connection.c
index f96355043e16..dc0a5cea67bf 100644
--- a/fs/smb/common/smbdirect/smbdirect_connection.c
+++ b/fs/smb/common/smbdirect/smbdirect_connection.c
@@ -69,6 +69,47 @@ static void smbdirect_connection_wake_up_all(struct smbdirect_socket *sc)
 	wake_up_all(&sc->mr_io.cleanup.wait_queue);
 }
 
+__maybe_unused /* this is temporary while this file is included in orders */
+static struct smbdirect_recv_io *smbdirect_connection_get_recv_io(struct smbdirect_socket *sc)
+{
+	struct smbdirect_recv_io *msg = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&sc->recv_io.free.lock, flags);
+	msg = list_first_entry_or_null(&sc->recv_io.free.list,
+				       struct smbdirect_recv_io,
+				       list);
+	if (likely(msg)) {
+		list_del(&msg->list);
+		sc->statistics.get_receive_buffer++;
+	}
+	spin_unlock_irqrestore(&sc->recv_io.free.lock, flags);
+
+	return msg;
+}
+
+__maybe_unused /* this is temporary while this file is included in orders */
+static void smbdirect_connection_put_recv_io(struct smbdirect_recv_io *msg)
+{
+	struct smbdirect_socket *sc = msg->socket;
+	unsigned long flags;
+
+	if (likely(msg->sge.length != 0)) {
+		ib_dma_unmap_single(sc->ib.dev,
+				    msg->sge.addr,
+				    msg->sge.length,
+				    DMA_FROM_DEVICE);
+		msg->sge.length = 0;
+	}
+
+	spin_lock_irqsave(&sc->recv_io.free.lock, flags);
+	list_add_tail(&msg->list, &sc->recv_io.free.list);
+	sc->statistics.put_receive_buffer++;
+	spin_unlock_irqrestore(&sc->recv_io.free.lock, flags);
+
+	queue_work(sc->workqueue, &sc->recv_io.posted.refill_work);
+}
+
 __maybe_unused /* this is temporary while this file is included in orders */
 static void smbdirect_connection_schedule_disconnect(struct smbdirect_socket *sc,
 						     int error)
-- 
2.43.0