[PATCH v2 030/127] smb: smbdirect: introduce smbdirect_connection_wait_for_credits()

[Stefan Metzmacher]

This is a copy of wait_for_credits() in the server, which
will be replaced by this soon.

This will allow us to share more common code between client
and server soon.

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>
---
 .../common/smbdirect/smbdirect_connection.c   | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/fs/smb/common/smbdirect/smbdirect_connection.c b/fs/smb/common/smbdirect/smbdirect_connection.c
index c1281807ff8c..1b84e0789d77 100644
--- a/fs/smb/common/smbdirect/smbdirect_connection.c
+++ b/fs/smb/common/smbdirect/smbdirect_connection.c
@@ -796,6 +796,33 @@ static void smbdirect_connection_idle_timer_work(struct work_struct *work)
 	queue_work(sc->workqueue, &sc->idle.immediate_work);
 }
 
+__maybe_unused /* this is temporary while this file is included in orders */
+static int smbdirect_connection_wait_for_credits(struct smbdirect_socket *sc,
+						 wait_queue_head_t *waitq,
+						 atomic_t *total_credits,
+						 int needed)
+{
+	int ret;
+
+	if (WARN_ON_ONCE(needed < 0))
+		return -EINVAL;
+
+	do {
+		if (atomic_sub_return(needed, total_credits) >= 0)
+			return 0;
+
+		atomic_add(needed, total_credits);
+		ret = wait_event_interruptible(*waitq,
+					       atomic_read(total_credits) >= needed ||
+					       sc->status != SMBDIRECT_SOCKET_CONNECTED);
+
+		if (sc->status != SMBDIRECT_SOCKET_CONNECTED)
+			return -ENOTCONN;
+		else if (ret < 0)
+			return ret;
+	} while (true);
+}
+
 __maybe_unused /* this is temporary while this file is included in orders */
 static void smbdirect_connection_send_io_done(struct ib_cq *cq, struct ib_wc *wc)
 {
-- 
2.43.0