scsi: core: Log SCSI command age with errors

Couple of users had requested to print the SCSI command age along with
command failure errors. This is a small change, but allows users to get
more important information about the command that was failed, it would help
the users in debugging the command failures:

Link: https://lore.kernel.org/r/20190926052501.GA8352@machine1
Signed-off-by: Milan P. Gandhi <mgandhi@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_logging.c b/drivers/scsi/scsi_logging.c
index c6ed0b12e8071b0dc02dea0a2b3c4160c6eebadd..c91fa3feb9300ecfe93864f2dc6718266c91a185 100644 (file)
--- a/drivers/scsi/scsi_logging.c
+++ b/drivers/scsi/scsi_logging.c
@@ -390,6 +390,7 @@ void scsi_print_result(const struct scsi_cmnd *cmd, const char *msg,
        const char *mlret_string = scsi_mlreturn_string(disposition);
        const char *hb_string = scsi_hostbyte_string(cmd->result);
        const char *db_string = scsi_driverbyte_string(cmd->result);
+       unsigned long cmd_age = (jiffies - cmd->jiffies_at_alloc) / HZ;
 
        logbuf = scsi_log_reserve_buffer(&logbuf_len);
        if (!logbuf)
@@ -431,10 +432,15 @@ void scsi_print_result(const struct scsi_cmnd *cmd, const char *msg,
 
        if (db_string)
                off += scnprintf(logbuf + off, logbuf_len - off,
-                                "driverbyte=%s", db_string);
+                                "driverbyte=%s ", db_string);
        else
                off += scnprintf(logbuf + off, logbuf_len - off,
-                                "driverbyte=0x%02x", driver_byte(cmd->result));
+                                "driverbyte=0x%02x ",
+                                driver_byte(cmd->result));
+
+       off += scnprintf(logbuf + off, logbuf_len - off,
+                        "cmd_age=%lus", cmd_age);
+
 out_printk:
        dev_printk(KERN_INFO, &cmd->device->sdev_gendev, "%s", logbuf);
        scsi_log_release_buffer(logbuf);