[SCSI] libfc: fixed a read IO data integrity issue when a IO data frame lost

The fc_fcp_complete_locked detected data underrun in this case and set
the FC_DATA_UNDRUN but that was ignored by fc_io_compl for all cases
including read underrun.

Added code to not to ignore FC_DATA_UNDRUN for read IO and instead
suggested scsi-ml to retry cmd to  recover from lost data frame.

Not sure if it is okay to ignore FC_DATA_UNDRUN for other case, so let
code as is for other cases but removed or-ing with zero valued fsp->cdb_status
for those cases.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index f440aaca39c21a514b11d7a06ade9287ff78f8d8..ecc72612c3859a0e86105dc865ec86c60ad6a66a 100644 (file)
--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -1810,12 +1810,12 @@ static void fc_io_compl(struct fc_fcp_pkt *fsp)
                sc_cmd->result = DID_ERROR << 16;
                break;
        case FC_DATA_UNDRUN:
-               if (fsp->cdb_status == 0) {
+               if ((fsp->cdb_status == 0) && !(fsp->req_flags & FC_SRB_READ)) {
                        /*
                         * scsi status is good but transport level
-                        * underrun. for read it should be an error??
+                        * underrun.
                         */
-                       sc_cmd->result = (DID_OK << 16) | fsp->cdb_status;
+                       sc_cmd->result = DID_OK << 16;
                } else {
                        /*
                         * scsi got underrun, this is an error