From: Aurelien Aptel <aaptel@suse.com>
Date: Wed, 22 Apr 2020 15:58:57 +0200
Subject: [PATCH] cifs: multichannel: move channel selection in function
Git-commit: 5f68ea4aa98bcddb5ec5229d2a0933d84ed17732
Patch-mainline: v5.8-rc1
References: bsc#1192606

This commit moves channel picking code in separate function.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/cifsproto.h |  1 +
 fs/cifs/transport.c | 38 +++++++++++++++++++++++++++-----------
 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 8036216ce434..9767f9b5d315 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -96,6 +96,7 @@ extern int cifs_call_async(struct TCP_Server_Info *server,
 			mid_receive_t *receive, mid_callback_t *callback,
 			mid_handle_t *handle, void *cbdata, const int flags,
 			const struct cifs_credits *exist_credits);
+extern struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses);
 extern int cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
 			  struct smb_rqst *rqst, int *resp_buf_type,
 			  const int flags, struct kvec *resp_iov);
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index c359221d6848..4d4cb26d2ae1 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -992,6 +992,32 @@ cifs_cancelled_callback(struct mid_q_entry *mid)
 	DeleteMidQEntry(mid);
 }
 
+/*
+ * Return a channel (master if none) of @ses that can be used to send
+ * regular requests.
+ *
+ * If we are currently binding a new channel (negprot/sess.setup),
+ * return the new incomplete channel.
+ */
+struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses)
+{
+	uint index = 0;
+
+	if (!ses)
+		return NULL;
+
+	if (!ses->binding) {
+		/* round robin */
+		if (ses->chan_count > 1) {
+			index = (uint)atomic_inc_return(&ses->chan_seq);
+			index %= ses->chan_count;
+		}
+		return ses->chans[index].server;
+	} else {
+		return cifs_ses_server(ses);
+	}
+}
+
 int
 compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 		   const int flags, const int num_rqst, struct smb_rqst *rqst,
@@ -1017,17 +1043,7 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 		return -EIO;
 	}
 
-	if (!ses->binding) {
-		uint index = 0;
-
-		if (ses->chan_count > 1) {
-			index = (uint)atomic_inc_return(&ses->chan_seq);
-			index %= ses->chan_count;
-		}
-		server = ses->chans[index].server;
-	} else {
-		server = cifs_ses_server(ses);
-	}
+	server = cifs_pick_channel(ses);
 
 	if (server->tcpStatus == CifsExiting)
 		return -ENOENT;
-- 
2.33.1