cifs: add a callback function to receive the rest of the frame

In order to handle larger SMBs for readpages and other calls, we want
to be able to read into a preallocated set of buffers. Rather than
changing all of the existing code to preallocate buffers however, we
instead add a receive callback function to the MID.

cifsd will call this function once the mid_q_entry has been identified
in order to receive the rest of the SMB. If the mid can't be identified
or the receive pointer is unset, then the standard 3rd phase receive
function will be called.

Reviewed-and-Tested-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 33a3fbf3a3a5..e7398d0cd054 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -339,8 +339,8 @@ wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
  */
 int
 cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
-                unsigned int nvec, mid_callback_t *callback, void *cbdata,
-                bool ignore_pend)
+                unsigned int nvec, mid_receive_t *receive,
+                mid_callback_t *callback, void *cbdata, bool ignore_pend)
 {
         int rc;
         struct mid_q_entry *mid;
@@ -374,6 +374,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
                 goto out_err;
         }
 
+        mid->receive = receive;
         mid->callback = callback;
         mid->callback_data = cbdata;
         mid->midState = MID_REQUEST_SUBMITTED;