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authorNicholas Bellinger <nab@linux-iscsi.org>2016-05-17 22:19:10 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2016-07-20 00:58:38 -0700
commitdff0ca9ea7dc8be2181a62df4a722c32ce68ff4a (patch)
tree5a8fad3a30d78857da00f4be6952c4f16c95f35c /drivers/target
parentea263c7fada4af8ec7fe5fcfd6e7d7705a89351b (diff)
downloadlinux-dff0ca9ea7dc8be2181a62df4a722c32ce68ff4a.tar.bz2
target: Fix ordered task target_setup_cmd_from_cdb exception hang
If a command with a Simple task attribute is failed due to a Unit Attention, then a subsequent command with an Ordered task attribute will hang forever. The reason for this is that the Unit Attention status is checked for in target_setup_cmd_from_cdb, before the call to target_execute_cmd, which calls target_handle_task_attr, which in turn increments dev->simple_cmds. However, transport_generic_request_failure still calls transport_complete_task_attr, which will decrement dev->simple_cmds. In this case, simple_cmds is now -1. So when a command with the Ordered task attribute is sent, target_handle_task_attr sees that dev->simple_cmds is not 0, so it decides it can't execute the command until all the (nonexistent) Simple commands have completed. Reported-by: Michael Cyr <mikecyr@linux.vnet.ibm.com> Tested-by: Michael Cyr <mikecyr@linux.vnet.ibm.com> Reported-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com> Tested-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com> Cc: stable@vger.kernel.org # 4.4+ Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_internal.h1
-rw-r--r--drivers/target/target_core_sbc.c2
-rw-r--r--drivers/target/target_core_transport.c62
3 files changed, 37 insertions, 28 deletions
diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index fc91e85f54ba..e2c970a9d61c 100644
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -146,6 +146,7 @@ sense_reason_t target_cmd_size_check(struct se_cmd *cmd, unsigned int size);
void target_qf_do_work(struct work_struct *work);
bool target_check_wce(struct se_device *dev);
bool target_check_fua(struct se_device *dev);
+void __target_execute_cmd(struct se_cmd *, bool);
/* target_core_stat.c */
void target_stat_setup_dev_default_groups(struct se_device *);
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index a9057aa07176..04f616b3ba0a 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -602,7 +602,7 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes
cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT;
spin_unlock_irq(&cmd->t_state_lock);
- __target_execute_cmd(cmd);
+ __target_execute_cmd(cmd, false);
kfree(buf);
return ret;
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 38bf2dcf926a..a6e1edcfefbd 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1303,23 +1303,6 @@ target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
trace_target_sequencer_start(cmd);
- /*
- * Check for an existing UNIT ATTENTION condition
- */
- ret = target_scsi3_ua_check(cmd);
- if (ret)
- return ret;
-
- ret = target_alua_state_check(cmd);
- if (ret)
- return ret;
-
- ret = target_check_reservation(cmd);
- if (ret) {
- cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
- return ret;
- }
-
ret = dev->transport->parse_cdb(cmd);
if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
@@ -1761,20 +1744,45 @@ queue_full:
}
EXPORT_SYMBOL(transport_generic_request_failure);
-void __target_execute_cmd(struct se_cmd *cmd)
+void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
{
sense_reason_t ret;
- if (cmd->execute_cmd) {
- ret = cmd->execute_cmd(cmd);
- if (ret) {
- spin_lock_irq(&cmd->t_state_lock);
- cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
- spin_unlock_irq(&cmd->t_state_lock);
+ if (!cmd->execute_cmd) {
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err;
+ }
+ if (do_checks) {
+ /*
+ * Check for an existing UNIT ATTENTION condition after
+ * target_handle_task_attr() has done SAM task attr
+ * checking, and possibly have already defered execution
+ * out to target_restart_delayed_cmds() context.
+ */
+ ret = target_scsi3_ua_check(cmd);
+ if (ret)
+ goto err;
+
+ ret = target_alua_state_check(cmd);
+ if (ret)
+ goto err;
- transport_generic_request_failure(cmd, ret);
+ ret = target_check_reservation(cmd);
+ if (ret) {
+ cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
+ goto err;
}
}
+
+ ret = cmd->execute_cmd(cmd);
+ if (!ret)
+ return;
+err:
+ spin_lock_irq(&cmd->t_state_lock);
+ cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
+ spin_unlock_irq(&cmd->t_state_lock);
+
+ transport_generic_request_failure(cmd, ret);
}
static int target_write_prot_action(struct se_cmd *cmd)
@@ -1899,7 +1907,7 @@ void target_execute_cmd(struct se_cmd *cmd)
return;
}
- __target_execute_cmd(cmd);
+ __target_execute_cmd(cmd, true);
}
EXPORT_SYMBOL(target_execute_cmd);
@@ -1923,7 +1931,7 @@ static void target_restart_delayed_cmds(struct se_device *dev)
list_del(&cmd->se_delayed_node);
spin_unlock(&dev->delayed_cmd_lock);
- __target_execute_cmd(cmd);
+ __target_execute_cmd(cmd, true);
if (cmd->sam_task_attr == TCM_ORDERED_TAG)
break;