[PATCH 5/5] scsi:scsi_debug: set command's result and sense data if the error is injected

[Wenchao Hao]

If a fail commnd error is injected, set the command's status and sense
data then finish this scsi command.

For example, the following command would make read(0x88) command finished
with UNC for 8 times:
  error=/sys/class/scsi_device/0:0:0:1/device/error_inject/error
  echo "2 -8 0x88 0 0 0x2 0x3 0x11 0x0" >$error

Signed-off-by: Wenchao Hao <haowenchao2@xxxxxxxxxx>
---
 drivers/scsi/scsi_debug.c | 46 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 1deccf8dfc90..863e1a23c055 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7788,6 +7788,41 @@ static int sdebug_fail_queue_cmd(struct scsi_cmnd *cmnd)
 	return 0;
 }
 
+static int sdebug_fail_cmd(struct scsi_cmnd *cmnd, int *retval,
+			   struct sdebug_err_inject *info)
+{
+	struct scsi_device *sdp = cmnd->device;
+	struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdp->hostdata;
+	struct sdebug_err_inject *err;
+	unsigned char *cmd = cmnd->cmnd;
+	int ret = 0;
+	int result;
+
+	if (devip == NULL)
+		return 0;
+
+	list_for_each_entry(err, &devip->inject_err_list, list) {
+		if (err->type == ERR_FAIL_CMD &&
+		    (err->cmd == cmd[0] || err->cmd == 0xff)) {
+			if (!err->cnt)
+				return 0;
+			ret = !!err->cnt;
+			goto out_handle;
+		}
+	}
+	return 0;
+
+out_handle:
+	if (err->cnt < 0)
+		err->cnt++;
+	mk_sense_buffer(cmnd, err->sense_key, err->asc, err->asq);
+	result = err->status_byte | err->host_byte << 16 | err->driver_byte << 24;
+	*info = *err;
+	*retval = schedule_resp(cmnd, devip, result, NULL, 0, 0);
+
+	return ret;
+}
+
 static int scsi_debug_queuecommand(struct Scsi_Host *shost,
 				   struct scsi_cmnd *scp)
 {
@@ -7808,6 +7843,7 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
 	bool has_wlun_rl;
 	bool inject_now;
 	int ret = 0;
+	struct sdebug_err_inject err;
 
 	scsi_set_resid(scp, 0);
 	if (sdebug_statistics) {
@@ -7860,6 +7896,16 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
 		return ret;
 	}
 
+	if (sdebug_fail_cmd(scp, &ret, &err)) {
+		scmd_printk(KERN_INFO, scp,
+			"fail command 0x%x with hostbyte=0x%x, "
+			"driverbyte=0x%x, statusbyte=0x%x, "
+			"sense_key=0x%x, asc=0x%x, asq=0x%x\n",
+			opcode, err.host_byte, err.driver_byte,
+			err.status_byte, err.sense_key, err.asc, err.asq);
+		return ret;
+	}
+
 	if (unlikely(inject_now && !atomic_read(&sdeb_inject_pending)))
 		atomic_set(&sdeb_inject_pending, 1);
 
-- 
2.35.3