Currently netlink command reply support option
(TCMU_ATTR_SUPP_KERN_CMD_REPLY) can be enabled only on module
scope. Because of that, once an application enables the netlink
command reply support, all applications using target_core_user.ko
would be expected to support the netlink reply. To make matters worse,
users will not be able to add a device via configfs manually.
To fix these issues, this patch adds an option to make netlink command
reply disabled on each device through configfs. Original
TCMU_ATTR_SUPP_KERN_CMD_REPLY is still enabled on module scope to keep
backward-compatibility and used by default, however once users set
nl_reply_supported=<NAGATIVE_VALUE> via configfs for a particular
device, the device disables the netlink command reply support.
Signed-off-by: Kenjiro Nakayama <nakayamakenjiro@xxxxxxxxx>
---
drivers/target/target_core_user.c | 59 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 58 insertions(+), 1 deletion(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 942d094269fb..709c27ed4206 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -150,6 +150,8 @@ struct tcmu_dev {
wait_queue_head_t nl_cmd_wq;
char dev_config[TCMU_CONFIG_LEN];
+
+ int nl_reply_supported;
};
#define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
@@ -1306,6 +1308,10 @@ static void tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
if (!tcmu_kern_cmd_reply_supported)
return;
+
+ if (udev->nl_reply_supported <= 0)
+ return;
+
relock:
spin_lock(&udev->nl_cmd_lock);
@@ -1332,6 +1338,9 @@ static int tcmu_wait_genl_cmd_reply(struct tcmu_dev *udev)
if (!tcmu_kern_cmd_reply_supported)
return 0;
+ if (udev->nl_reply_supported <= 0)
+ return 0;
+
pr_debug("sleeping for nl reply\n");
wait_for_completion(&nl_cmd->complete);
@@ -1506,6 +1515,12 @@ static int tcmu_configure_device(struct se_device *dev)
dev->dev_attrib.emulate_write_cache = 0;
dev->dev_attrib.hw_queue_depth = 128;
+ /* If user didn't explicitly disable netlink reply support, use
+ * module scope setting.
+ */
+ if (udev->nl_reply_supported >= 0)
+ udev->nl_reply_supported = tcmu_kern_cmd_reply_supported;
+
/*
* Get a ref incase userspace does a close on the uio device before
* LIO has initiated tcmu_free_device.
@@ -1610,7 +1625,7 @@ static void tcmu_destroy_device(struct se_device *dev)
enum {
Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
- Opt_err,
+ Opt_nl_reply_supported, Opt_err,
};
static match_table_t tokens = {
@@ -1618,6 +1633,7 @@ static match_table_t tokens = {
{Opt_dev_size, "dev_size=%u"},
{Opt_hw_block_size, "hw_block_size=%u"},
{Opt_hw_max_sectors, "hw_max_sectors=%u"},
+ {Opt_nl_reply_supported, "nl_reply_supported=%d"},
{Opt_err, NULL}
};
@@ -1692,6 +1708,18 @@ static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
ret = tcmu_set_dev_attrib(&args[0],
&(dev->dev_attrib.hw_max_sectors));
break;
+ case Opt_nl_reply_supported:
+ arg_p = match_strdup(&args[0]);
+ if (!arg_p) {
+ ret = -ENOMEM;
+ break;
+ }
+ ret = kstrtol(arg_p, 0,
+ (long int *) &udev->nl_reply_supported);
+ kfree(arg_p);
+ if (ret < 0)
+ pr_err("kstrtoul() failed for nl_reply_supported=\n");
+ break;
default:
break;
}
@@ -1842,6 +1870,34 @@ static ssize_t tcmu_dev_size_store(struct config_item *item, const char *page,
}
CONFIGFS_ATTR(tcmu_, dev_size);
+static ssize_t tcmu_nl_reply_supported_show(struct config_item *item,
+ char *page)
+{
+ struct se_dev_attrib *da = container_of(to_config_group(item),
+ struct se_dev_attrib, da_group);
+ struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
+
+ return snprintf(page, PAGE_SIZE, "%d\n", udev->nl_reply_supported);
+}
+
+static ssize_t tcmu_nl_reply_supported_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct se_dev_attrib *da = container_of(to_config_group(item),
+ struct se_dev_attrib, da_group);
+ struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
+ s8 val;
+ int ret;
+
+ ret = kstrtos8(page, 0, &val);
+ if (ret < 0)
+ return ret;
+
+ udev->nl_reply_supported = val;
+ return count;
+}
+CONFIGFS_ATTR(tcmu_, nl_reply_supported);
+
static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
char *page)
{
@@ -1884,6 +1940,7 @@ static struct configfs_attribute *tcmu_attrib_attrs[] = {
&tcmu_attr_dev_config,
&tcmu_attr_dev_size,
&tcmu_attr_emulate_write_cache,
+ &tcmu_attr_nl_reply_supported,
NULL,
};
