[SCSI] libiscsi: fix data corruption when target has to resend data-in packets
iscsi_tcp was updating the exp_statsn (exp_statsn acknowledges
status and tells the target it is ok to let the resources for
a iscsi pdu to be reused) before it got all the data for pdu read
into OS buffers. Data corruption was occuring if something happens
to a packet and the network layer requests a retransmit, and the
initiator has told the target about the udpated exp_statsn ack,
then the target may be sending data from a buffer it has reused
for a new iscsi pdu. This fixes the problem by having the LLD
(iscsi_tcp in this case) just handle the transferring of data, and
has libiscsi handle the processing of status (libiscsi completion
processing is done after LLD data transfers are complete).
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 0e8f26b..f9539af 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -633,6 +633,40 @@
__iscsi_put_task(task);
}
+/**
+ * iscsi_data_in_rsp - SCSI Data-In Response processing
+ * @conn: iscsi connection
+ * @hdr: iscsi pdu
+ * @task: scsi command task
+ **/
+static void
+iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
+ struct iscsi_task *task)
+{
+ struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)hdr;
+ struct scsi_cmnd *sc = task->sc;
+
+ if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
+ return;
+
+ sc->result = (DID_OK << 16) | rhdr->cmd_status;
+ conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
+ if (rhdr->flags & (ISCSI_FLAG_DATA_UNDERFLOW |
+ ISCSI_FLAG_DATA_OVERFLOW)) {
+ int res_count = be32_to_cpu(rhdr->residual_count);
+
+ if (res_count > 0 &&
+ (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
+ res_count <= scsi_in(sc)->length))
+ scsi_in(sc)->resid = res_count;
+ else
+ sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
+ }
+
+ conn->scsirsp_pdus_cnt++;
+ __iscsi_put_task(task);
+}
+
static void iscsi_tmf_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
{
struct iscsi_tm_rsp *tmf = (struct iscsi_tm_rsp *)hdr;
@@ -818,12 +852,7 @@
iscsi_scsi_cmd_rsp(conn, hdr, task, data, datalen);
break;
case ISCSI_OP_SCSI_DATA_IN:
- if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
- conn->scsirsp_pdus_cnt++;
- iscsi_update_cmdsn(session,
- (struct iscsi_nopin*) hdr);
- __iscsi_put_task(task);
- }
+ iscsi_data_in_rsp(conn, hdr, task);
break;
case ISCSI_OP_LOGOUT_RSP:
iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);