scsi: scsi_debug: Time out command if the error is injected

If a timeout error is injected, return 0 from scsi_debug_queuecommand to
make the command time out.

Time out SCSI command format:

  +--------+------+-------------------------------------------------------+
  | Column | Type | Description                                           |
  +--------+------+-------------------------------------------------------+
  |   1    |  u8  | Error type, fixed to 0x0                              |
  +--------+------+-------------------------------------------------------+
  |   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 "0 -10 0x12" > ${error}

will make the device's inquiry command time out 10 times.

    echo "0 1 0x12" > ${error}

will make the device's inquiry time out each time it is invoked on this
device.

Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
Link: https://lore.kernel.org/r/20231010092051.608007-5-haowenchao2@huawei.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 0d5a179dbd970d363cf793296a8cabd0c38b0b84..9081c9d22882162e981a320d8c19bd24fb1f351b 100644 (file)
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7741,6 +7741,34 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
        return num_entries;
 }
 
+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;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(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++;
+
+                       rcu_read_unlock();
+                       return ret;
+               }
+       }
+       rcu_read_unlock();
+
+       return 0;
+}
+
 static int scsi_debug_queuecommand(struct Scsi_Host *shost,
                                   struct scsi_cmnd *scp)
 {
@@ -7799,6 +7827,12 @@ 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);