[PATCH v6 07/10] scsi: scsi_debug: Add new error injection abort failed

[Wenchao Hao <haowenchao2@huawei.com>]

Add error injection type 3 to make scsi_debug_abort() return FAILED.
Fail abort command format:

  +--------+------+-------------------------------------------------------+
  | Column | Type | Description                                           |
  +--------+------+-------------------------------------------------------+
  |   1    |  u8  | Error type, fixed to 0x3                              |
  +--------+------+-------------------------------------------------------+
  |   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 "3 -10 0x12" > ${error}
will make the device return FAILED when abort inquiry command 10 times.

Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
---
 drivers/scsi/scsi_debug.c | 40 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index d15d007f1317..89f47ded1e23 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -293,6 +293,8 @@ enum sdebug_err_type {
 	ERR_FAIL_CMD		= 2,	/* make specific scsi command's */
 					/* queuecmd return succeed but */
 					/* with errors set in scsi_cmnd */
+	ERR_ABORT_CMD_FAILED	= 3,	/* control return FAILED from */
+					/* scsi_debug_abort() */
 };
 
 struct sdebug_err_inject {
@@ -970,6 +972,7 @@ static int sdebug_error_show(struct seq_file *m, void *p)
 	list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
 		switch (err->type) {
 		case ERR_TMOUT_CMD:
+		case ERR_ABORT_CMD_FAILED:
 			seq_printf(m, "%d\t%d\t0x%x\n", err->type, err->cnt,
 				err->cmd);
 		break;
@@ -1031,6 +1034,7 @@ 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:
 		if (sscanf(buf, "%d %d %hhx", &inject->type, &inject->cnt,
 			   &inject->cmd) != 3)
 			goto out_error;
@@ -5512,9 +5516,39 @@ static void stop_all_queued(void)
 	mutex_unlock(&sdebug_host_list_mutex);
 }
 
+static int sdebug_fail_abort(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_ABORT_CMD_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_abort(struct scsi_cmnd *SCpnt)
 {
 	bool ok = scsi_debug_abort_cmnd(SCpnt);
+	u8 *cmd = SCpnt->cmnd;
+	u8 opcode = cmd[0];
 
 	++num_aborts;
 
@@ -5523,6 +5557,12 @@ static int scsi_debug_abort(struct scsi_cmnd *SCpnt)
 			    "%s: command%s found\n", __func__,
 			    ok ? "" : " not");
 
+	if (sdebug_fail_abort(SCpnt)) {
+		scmd_printk(KERN_INFO, SCpnt, "fail abort command 0x%x\n",
+			    opcode);
+		return FAILED;
+	}
+
 	return SUCCESS;
 }
 
-- 
2.32.0