CIFS: Introduce credit-based flow control

and send no more than credits value requests at once. For SMB/CIFS
it's trivial: increment this value by receiving any message and
decrement by sending one.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 6f4e243e0f62..47a769e535b1 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -88,6 +88,9 @@ extern int SendReceiveBlockingLock(const unsigned int xid,
                         struct smb_hdr *in_buf ,
                         struct smb_hdr *out_buf,
                         int *bytes_returned);
+extern void cifs_add_credits(struct TCP_Server_Info *server,
+                             const unsigned int add);
+extern void cifs_set_credits(struct TCP_Server_Info *server, const int val);
 extern int checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int length);
 extern bool is_valid_oplock_break(struct smb_hdr *smb,
                                   struct TCP_Server_Info *);