[RFC PATCH 3/5] scsi:scsi_debug: make command timeout if timeout error is injected

[Wenchao Hao]

If a timeout error is injected for specific scsi command, just return
0 in queuecommand to make it timeout.

For example, the following command would inject timeout error for
inquiry(0x12) command for 10 times:
  echo "0 -10 0x12" >/sys/block/sdb/device/error_inject/error

Signed-off-by: Wenchao Hao <haowenchao@xxxxxxxxxx>
---
 drivers/scsi/scsi_debug.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 06e3150812fa..761e1e3bcb9a 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7784,6 +7784,30 @@ const struct attribute_group *sdebug_sdev_groups[] = {
 	NULL
 };
 
+static int sdebug_timeout_cmd(struct scsi_cmnd *cmnd)
+{
+	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;
+
+	if (devip == NULL)
+		return 0;
+
+	list_for_each_entry(err, &devip->inject_err_list, list) {
+		if (err->type == ERR_TMOUT_CMD &&
+		    (err->cmd == cmd[0] || err->cmd == 0xff)) {
+			ret = !!err->cnt;
+			if (err->cnt < 0)
+				err->cnt++;
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 static int scsi_debug_queuecommand(struct Scsi_Host *shost,
 				   struct scsi_cmnd *scp)
 {
@@ -7842,6 +7866,12 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
 		if (NULL == devip)
 			goto err_out;
 	}
+
+	if (sdebug_timeout_cmd(scp)) {
+		scmd_printk(KERN_INFO, scp, "timeout command 0x%x\n", opcode);
+		return 0;
+	}
+
 	if (unlikely(inject_now && !atomic_read(&sdeb_inject_pending)))
 		atomic_set(&sdeb_inject_pending, 1);
 
-- 
2.35.3