[PATCH 4.8 46/96] scsi: zfcp: do not trace pure benign residual HBA responses at default level

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

--

From: Steffen Maier 

commit 56d23ed7adf3974f10e91b643bd230e9c65b5f79 upstream.

Since quite a while, Linux issues enough SCSI commands per scsi_device
which successfully return with FCP_RESID_UNDER, FSF_FCP_RSP_AVAILABLE,
and SAM_STAT_GOOD.  This floods the HBA trace area and we cannot see
other and important HBA trace records long enough.

Therefore, do not trace HBA response errors for pure benign residual
under counts at the default trace level.

This excludes benign residual under count combined with other validity
bits set in FCP_RSP_IU, such as FCP_SNS_LEN_VAL.  For all those other
cases, we still do want to see both the HBA record and the corresponding
SCSI record by default.

Signed-off-by: Steffen Maier 
Fixes: a54ca0f62f95 ("[SCSI] zfcp: Redesign of the debug tracing for HBA 
records.")
Reviewed-by: Benjamin Block 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Greg Kroah-Hartman 

---
 drivers/s390/scsi/zfcp_dbf.h |   30 --
 drivers/s390/scsi/zfcp_fsf.h |3 ++-
 2 files changed, 30 insertions(+), 3 deletions(-)

--- a/drivers/s390/scsi/zfcp_dbf.h
+++ b/drivers/s390/scsi/zfcp_dbf.h
@@ -2,7 +2,7 @@
  * zfcp device driver
  * debug feature declarations
  *
- * Copyright IBM Corp. 2008, 2015
+ * Copyright IBM Corp. 2008, 2016
  */
 
 #ifndef ZFCP_DBF_H
@@ -283,6 +283,30 @@ struct zfcp_dbf {
struct zfcp_dbf_scsiscsi_buf;
 };
 
+/**
+ * zfcp_dbf_hba_fsf_resp_suppress - true if we should not trace by default
+ * @req: request that has been completed
+ *
+ * Returns true if FCP response with only benign residual under count.
+ */
+static inline
+bool zfcp_dbf_hba_fsf_resp_suppress(struct zfcp_fsf_req *req)
+{
+   struct fsf_qtcb *qtcb = req->qtcb;
+   u32 fsf_stat = qtcb->header.fsf_status;
+   struct fcp_resp *fcp_rsp;
+   u8 rsp_flags, fr_status;
+
+   if (qtcb->prefix.qtcb_type != FSF_IO_COMMAND)
+   return false; /* not an FCP response */
+   fcp_rsp = (struct fcp_resp *)>bottom.io.fcp_rsp;
+   rsp_flags = fcp_rsp->fr_flags;
+   fr_status = fcp_rsp->fr_status;
+   return (fsf_stat == FSF_FCP_RSP_AVAILABLE) &&
+   (rsp_flags == FCP_RESID_UNDER) &&
+   (fr_status == SAM_STAT_GOOD);
+}
+
 static inline
 void zfcp_dbf_hba_fsf_resp(char *tag, int level, struct zfcp_fsf_req *req)
 {
@@ -304,7 +328,9 @@ void zfcp_dbf_hba_fsf_response(struct zf
zfcp_dbf_hba_fsf_resp("fs_perr", 1, req);
 
} else if (qtcb->header.fsf_status != FSF_GOOD) {
-   zfcp_dbf_hba_fsf_resp("fs_ferr", 1, req);
+   zfcp_dbf_hba_fsf_resp("fs_ferr",
+ zfcp_dbf_hba_fsf_resp_suppress(req)
+ ? 5 : 1, req);
 
} else if ((req->fsf_command == FSF_QTCB_OPEN_PORT_WITH_DID) ||
   (req->fsf_command == FSF_QTCB_OPEN_LUN)) {
--- a/drivers/s390/scsi/zfcp_fsf.h
+++ b/drivers/s390/scsi/zfcp_fsf.h
@@ -3,7 +3,7 @@
  *
  * Interface to the FSF support functions.
  *
- * Copyright IBM Corp. 2002, 2015
+ * Copyright IBM Corp. 2002, 2016
  */
 
 #ifndef FSF_H
@@ -78,6 +78,7 @@
 #define FSF_APP_TAG_CHECK_FAILURE  0x0082
 #define FSF_REF_TAG_CHECK_FAILURE  0x0083
 #define FSF_ADAPTER_STATUS_AVAILABLE   0x00AD
+#define FSF_FCP_RSP_AVAILABLE  0x00AF
 #define FSF_UNKNOWN_COMMAND0x00E2
 #define FSF_UNKNOWN_OP_SUBTYPE  0x00E3
 #define FSF_INVALID_COMMAND_OPTION  0x00E5

[PATCH 4.8 46/96] scsi: zfcp: do not trace pure benign residual HBA responses at default level

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

--

From: Steffen Maier 

commit 56d23ed7adf3974f10e91b643bd230e9c65b5f79 upstream.

Since quite a while, Linux issues enough SCSI commands per scsi_device
which successfully return with FCP_RESID_UNDER, FSF_FCP_RSP_AVAILABLE,
and SAM_STAT_GOOD.  This floods the HBA trace area and we cannot see
other and important HBA trace records long enough.

Therefore, do not trace HBA response errors for pure benign residual
under counts at the default trace level.

This excludes benign residual under count combined with other validity
bits set in FCP_RSP_IU, such as FCP_SNS_LEN_VAL.  For all those other
cases, we still do want to see both the HBA record and the corresponding
SCSI record by default.

Signed-off-by: Steffen Maier 
Fixes: a54ca0f62f95 ("[SCSI] zfcp: Redesign of the debug tracing for HBA 
records.")
Reviewed-by: Benjamin Block 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Greg Kroah-Hartman 

---
 drivers/s390/scsi/zfcp_dbf.h |   30 --
 drivers/s390/scsi/zfcp_fsf.h |3 ++-
 2 files changed, 30 insertions(+), 3 deletions(-)

--- a/drivers/s390/scsi/zfcp_dbf.h
+++ b/drivers/s390/scsi/zfcp_dbf.h
@@ -2,7 +2,7 @@
  * zfcp device driver
  * debug feature declarations
  *
- * Copyright IBM Corp. 2008, 2015
+ * Copyright IBM Corp. 2008, 2016
  */
 
 #ifndef ZFCP_DBF_H
@@ -283,6 +283,30 @@ struct zfcp_dbf {
struct zfcp_dbf_scsiscsi_buf;
 };
 
+/**
+ * zfcp_dbf_hba_fsf_resp_suppress - true if we should not trace by default
+ * @req: request that has been completed
+ *
+ * Returns true if FCP response with only benign residual under count.
+ */
+static inline
+bool zfcp_dbf_hba_fsf_resp_suppress(struct zfcp_fsf_req *req)
+{
+   struct fsf_qtcb *qtcb = req->qtcb;
+   u32 fsf_stat = qtcb->header.fsf_status;
+   struct fcp_resp *fcp_rsp;
+   u8 rsp_flags, fr_status;
+
+   if (qtcb->prefix.qtcb_type != FSF_IO_COMMAND)
+   return false; /* not an FCP response */
+   fcp_rsp = (struct fcp_resp *)>bottom.io.fcp_rsp;
+   rsp_flags = fcp_rsp->fr_flags;
+   fr_status = fcp_rsp->fr_status;
+   return (fsf_stat == FSF_FCP_RSP_AVAILABLE) &&
+   (rsp_flags == FCP_RESID_UNDER) &&
+   (fr_status == SAM_STAT_GOOD);
+}
+
 static inline
 void zfcp_dbf_hba_fsf_resp(char *tag, int level, struct zfcp_fsf_req *req)
 {
@@ -304,7 +328,9 @@ void zfcp_dbf_hba_fsf_response(struct zf
zfcp_dbf_hba_fsf_resp("fs_perr", 1, req);
 
} else if (qtcb->header.fsf_status != FSF_GOOD) {
-   zfcp_dbf_hba_fsf_resp("fs_ferr", 1, req);
+   zfcp_dbf_hba_fsf_resp("fs_ferr",
+ zfcp_dbf_hba_fsf_resp_suppress(req)
+ ? 5 : 1, req);
 
} else if ((req->fsf_command == FSF_QTCB_OPEN_PORT_WITH_DID) ||
   (req->fsf_command == FSF_QTCB_OPEN_LUN)) {
--- a/drivers/s390/scsi/zfcp_fsf.h
+++ b/drivers/s390/scsi/zfcp_fsf.h
@@ -3,7 +3,7 @@
  *
  * Interface to the FSF support functions.
  *
- * Copyright IBM Corp. 2002, 2015
+ * Copyright IBM Corp. 2002, 2016
  */
 
 #ifndef FSF_H
@@ -78,6 +78,7 @@
 #define FSF_APP_TAG_CHECK_FAILURE  0x0082
 #define FSF_REF_TAG_CHECK_FAILURE  0x0083
 #define FSF_ADAPTER_STATUS_AVAILABLE   0x00AD
+#define FSF_FCP_RSP_AVAILABLE  0x00AF
 #define FSF_UNKNOWN_COMMAND0x00E2
 #define FSF_UNKNOWN_OP_SUBTYPE  0x00E3
 #define FSF_INVALID_COMMAND_OPTION  0x00E5