scsi: scsi_debug: Add new error injection type: Reset LUN failed

Add error injection type 4 to make scsi_debug_device_reset() return FAILED.
Fail abort command format:

  +--------+------+-------------------------------------------------------+
  | Column | Type | Description                                           |
  +--------+------+-------------------------------------------------------+
  |   1    |  u8  | Error type, fixed to 0x4                              |
  +--------+------+-------------------------------------------------------+
  |   2    |  s32 | Error count                                           |
  |        |      |  0: this rule will be ignored                         |
  |        |      |  positive: the rule will always take effect           |
  |        |      |  negative: the rule takes effect n times where -n is  |
  |        |      |            the value given. Ignored after n times     |
  +--------+------+-------------------------------------------------------+
  |   3    |  x8  | SCSI command opcode, 0xff for all commands            |
  +--------+------+-------------------------------------------------------+

Examples:

    error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
    echo "4 -10 0x12" > ${error}

will make the device return FAILED when trying to reset LUN with inquiry
command 10 times.

    error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
    echo "4 -10 0xff" > ${error}

will make the device return FAILED when trying to reset LUN 10 times.

Usually we do not care about what command it is when trying to perform
reset LUN, so 0xff could be applied.

Signed-off-by: Wenchao Hao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Tested-by: Douglas Gilbert <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: wenchao-hao

Diff for: drivers/scsi/scsi_debug.c

@@ -295,6 +295,8 @@ enum sdebug_err_type {
 					/* with errors set in scsi_cmnd */
 	ERR_ABORT_CMD_FAILED	= 3,	/* control return FAILED from */
 					/* scsi_debug_abort() */
+	ERR_LUN_RESET_FAILED	= 4,	/* control return FAILED from */
+					/* scsi_debug_device_reseLUN_RESET_FAILEDt() */
 };
 
 struct sdebug_err_inject {
@@ -973,6 +975,7 @@ static int sdebug_error_show(struct seq_file *m, void *p)
 		switch (err->type) {
 		case ERR_TMOUT_CMD:
 		case ERR_ABORT_CMD_FAILED:
+		case ERR_LUN_RESET_FAILED:
 			seq_printf(m, "%d\t%d\t0x%x\n", err->type, err->cnt,
 				err->cmd);
 		break;
@@ -1035,6 +1038,7 @@ static ssize_t sdebug_error_write(struct file *file, const char __user *ubuf,
 	switch (inject_type) {
 	case ERR_TMOUT_CMD:
 	case ERR_ABORT_CMD_FAILED:
+	case ERR_LUN_RESET_FAILED:
 		if (sscanf(buf, "%d %d %hhx", &inject->type, &inject->cnt,
 			   &inject->cmd) != 3)
 			goto out_error;
@@ -5586,10 +5590,40 @@ static void scsi_debug_stop_all_queued(struct scsi_device *sdp)
 				scsi_debug_stop_all_queued_iter, sdp);
 }
 
+static int sdebug_fail_lun_reset(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;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+		if (err->type == ERR_LUN_RESET_FAILED &&
+		    (err->cmd == cmd[0] || err->cmd == 0xff)) {
+			ret = !!err->cnt;
+			if (err->cnt < 0)
+				err->cnt++;
+
+			rcu_read_unlock();
+			return ret;
+		}
+	}
+	rcu_read_unlock();
+
+	return 0;
+}
+
 static int scsi_debug_device_reset(struct scsi_cmnd *SCpnt)
 {
 	struct scsi_device *sdp = SCpnt->device;
 	struct sdebug_dev_info *devip = sdp->hostdata;
+	u8 *cmd = SCpnt->cmnd;
+	u8 opcode = cmd[0];
 
 	++num_dev_resets;
 
@@ -5600,6 +5634,11 @@ static int scsi_debug_device_reset(struct scsi_cmnd *SCpnt)
 	if (devip)
 		set_bit(SDEBUG_UA_POR, devip->uas_bm);
 
+	if (sdebug_fail_lun_reset(SCpnt)) {
+		scmd_printk(KERN_INFO, SCpnt, "fail lun reset 0x%x\n", opcode);
+		return FAILED;
+	}
+
 	return SUCCESS;
 }