[SCSI] libfc: fix ddp in fc_fcp for 0 xid

xid 0 was used as an indication of invalid xid before but now xid 0
can be used as a valid exchange i. This patch fixes the ddp completion
in fcp layer, i.e., in fc_fcp.c:fc_fcp_ddp_done() function, to make sure it
does not use xid 0 for indication of an invalid xid, instead, it now
uses use FC_XID_UNKNOWN for such indication.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index 59a4408b27b5..e6c6f4742368 100644
--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -302,10 +302,13 @@ static void fc_fcp_ddp_done(struct fc_fcp_pkt *fsp)
         if (!fsp)
                 return;
 
+        if (fsp->xfer_ddp == FC_XID_UNKNOWN)
+                return;
+
         lp = fsp->lp;
-        if (fsp->xfer_ddp && lp->tt.ddp_done) {
+        if (lp->tt.ddp_done) {
                 fsp->xfer_len = lp->tt.ddp_done(lp, fsp->xfer_ddp);
-                fsp->xfer_ddp = 0;
+                fsp->xfer_ddp = FC_XID_UNKNOWN;
         }
 }
 
@@ -1708,6 +1711,7 @@ int fc_queuecommand(struct scsi_cmnd *sc_cmd, void (*done)(struct scsi_cmnd *))
         fsp->cmd = sc_cmd;      /* save the cmd */
         fsp->lp = lp;           /* save the softc ptr */
         fsp->rport = rport;     /* set the remote port ptr */
+        fsp->xfer_ddp = FC_XID_UNKNOWN;
         sc_cmd->scsi_done = done;
 
         /*