From: Xiubo Li <xiubli@xxxxxxxxxx>
This patch adds 1 tcmu attr to reset and complete all the blocked
netlink waiting threads. It's used when the userspace daemon like
tcmu-runner has crashed or forced to shutdown just before the
netlink requests be replied to the kernel, then the netlink requeting
threads will get stuck forever. We must reboot the machine to recover
from it and by this the rebootng is not a must then.
The netlink reset operation should be done before the userspace daemon
could receive and handle the netlink requests to be safe.
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---
drivers/target/target_core_user.c | 99 ++++++++++++++++++++++++++++++++++++---
1 file changed, 93 insertions(+), 6 deletions(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 4ad89ea..dc8879d 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -103,9 +103,13 @@ struct tcmu_hba {
#define TCMU_CONFIG_LEN 256
+static spinlock_t nl_complete_lock;
+static struct idr complete_wait_udevs = IDR_INIT;
+
struct tcmu_nl_cmd {
/* wake up thread waiting for reply */
- struct completion complete;
+ bool complete;
+
int cmd;
int status;
};
@@ -159,12 +163,17 @@ struct tcmu_dev {
spinlock_t nl_cmd_lock;
struct tcmu_nl_cmd curr_nl_cmd;
- /* wake up threads waiting on curr_nl_cmd */
+ /* wake up threads waiting on nl_cmd_wq */
wait_queue_head_t nl_cmd_wq;
+ /* complete thread waiting complete_wq */
+ wait_queue_head_t complete_wq;
+
char dev_config[TCMU_CONFIG_LEN];
int nl_reply_supported;
+
+ uint32_t dev_id;
};
#define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
@@ -251,6 +260,56 @@ static int tcmu_get_global_max_data_area(char *buffer,
"Max MBs allowed to be allocated to all the tcmu device's "
"data areas.");
+static void tcmu_complete_wake_up(struct tcmu_dev *udev)
+{
+ struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
+
+ spin_lock(&nl_complete_lock);
+ nl_cmd->complete = true;
+ wake_up(&udev->complete_wq);
+ spin_unlock(&nl_complete_lock);
+}
+
+static void tcmu_complete_wake_up_all(void)
+{
+ struct tcmu_nl_cmd *nl_cmd;
+ struct tcmu_dev *udev;
+ int i;
+
+ spin_lock(&nl_complete_lock);
+ idr_for_each_entry(&complete_wait_udevs, udev, i) {
+ nl_cmd = &udev->curr_nl_cmd;
+ nl_cmd->complete = true;
+ wake_up(&udev->complete_wq);
+ }
+ spin_unlock(&nl_complete_lock);
+}
+
+static int tcmu_complete_wait(struct tcmu_dev *udev)
+{
+ struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
+ uint32_t dev_id;
+
+ spin_lock(&nl_complete_lock);
+ dev_id = idr_alloc(&complete_wait_udevs, udev, 1, USHRT_MAX, GFP_NOWAIT);
+ if (dev_id < 0) {
+ pr_err("tcmu: Could not allocate dev id.\n");
+ return dev_id;
+ }
+ udev->dev_id = dev_id;
+ spin_unlock(&nl_complete_lock);
+
+ pr_debug("sleeping for nl reply\n");
+ wait_event(udev->complete_wq, nl_cmd->complete);
+
+ spin_lock(&nl_complete_lock);
+ nl_cmd->complete = false;
+ idr_remove(&complete_wait_udevs, dev_id);
+ spin_unlock(&nl_complete_lock);
+
+ return 0;
+}
+
/* multicast group */
enum tcmu_multicast_groups {
TCMU_MCGRP_CONFIG,
@@ -311,7 +370,7 @@ static int tcmu_genl_cmd_done(struct genl_info *info, int completed_cmd)
if (!is_removed)
target_undepend_item(&dev->dev_group.cg_item);
if (!ret)
- complete(&nl_cmd->complete);
+ tcmu_complete_wake_up(udev);
return ret;
}
@@ -1258,6 +1317,7 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
timer_setup(&udev->cmd_timer, tcmu_cmd_timedout, 0);
init_waitqueue_head(&udev->nl_cmd_wq);
+ init_waitqueue_head(&udev->complete_wq);
spin_lock_init(&udev->nl_cmd_lock);
INIT_RADIX_TREE(&udev->data_blocks, GFP_KERNEL);
@@ -1462,7 +1522,11 @@ static void tcmu_dev_call_rcu(struct rcu_head *p)
kfree(udev->uio_info.name);
kfree(udev->name);
+
+ spin_lock(&nl_complete_lock);
+ idr_remove(&complete_wait_udevs, udev->dev_id);
kfree(udev);
+ spin_unlock(&nl_complete_lock);
}
static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
@@ -1555,7 +1619,6 @@ static void tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
memset(nl_cmd, 0, sizeof(*nl_cmd));
nl_cmd->cmd = cmd;
- init_completion(&nl_cmd->complete);
spin_unlock(&udev->nl_cmd_lock);
}
@@ -1572,8 +1635,9 @@ static int tcmu_wait_genl_cmd_reply(struct tcmu_dev *udev)
if (udev->nl_reply_supported <= 0)
return 0;
- pr_debug("sleeping for nl reply\n");
- wait_for_completion(&nl_cmd->complete);
+ ret = tcmu_complete_wait(udev);
+ if (ret)
+ return ret;
spin_lock(&udev->nl_cmd_lock);
nl_cmd->cmd = TCMU_CMD_UNSPEC;
@@ -2323,6 +2387,26 @@ static ssize_t tcmu_block_dev_store(struct config_item *item, const char *page,
}
CONFIGFS_ATTR(tcmu_, block_dev);
+static ssize_t tcmu_reset_netlink_store(struct config_item *item, const char *page,
+ size_t count)
+{
+ u8 val;
+ int ret;
+
+ ret = kstrtou8(page, 0, &val);
+ if (ret < 0)
+ return ret;
+
+ if (val != 1) {
+ pr_err("Invalid block value %d\n", val);
+ return -EINVAL;
+ }
+
+ tcmu_complete_wake_up_all();
+ return count;
+}
+CONFIGFS_ATTR_WO(tcmu_, reset_netlink);
+
static ssize_t tcmu_reset_ring_store(struct config_item *item, const char *page,
size_t count)
{
@@ -2363,6 +2447,7 @@ static ssize_t tcmu_reset_ring_store(struct config_item *item, const char *page,
static struct configfs_attribute *tcmu_action_attrs[] = {
&tcmu_attr_block_dev,
&tcmu_attr_reset_ring,
+ &tcmu_attr_reset_netlink,
NULL,
};
@@ -2519,6 +2604,8 @@ static int __init tcmu_module_init(void)
}
tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
+ spin_lock_init(&nl_complete_lock);
+
ret = transport_backend_register(&tcmu_ops);
if (ret)
goto out_attrs;
--
1.8.3.1
