[Open-FCoE] [PATCH] libfc: fixed a read IO data integrity issue when a IO data frame lost

Vasu Dev vasu.dev at intel.com
Fri Jan 23 02:19:42 UTC 2009


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.

Please ignore previously submitted patch fixing this issue differently at
http://www.open-fcoe.org/pipermail/devel/2009-January/001543.html.
Although that patch also fixed this issue but was causing unnecessary
FC abort to trigger scsi-ml retry to recover from this underrun issue.

Signed-off-by: Vasu Dev <vasu.dev at intel.com>
---

 drivers/scsi/libfc/fc_fcp.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)


diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index f440aac..ecc7261 100644
--- 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




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