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Commit b849b456 authored by Kenjiro Nakayama's avatar Kenjiro Nakayama Committed by Nicholas Bellinger
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target: Add netlink command reply supported option for each device 



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: default avatarKenjiro Nakayama <nakayamakenjiro@gmail.com>
Reviewed-by: default avatarMike Christie <mchristi@redhat.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent b5ab697c

drivers/target/target_core_user.c

+58 −1
Original line number Diff line number Diff line
@@ -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)
@@ -1352,6 +1354,10 @@ 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);
@@ -1378,6 +1384,9 @@ 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);
@@ -1550,6 +1559,12 @@ 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.
@@ -1612,7 +1627,7 @@ 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 = {
@@ -1620,6 +1635,7 @@ 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}

};
@@ -1694,6 +1710,18 @@ 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;

		}
@@ -1843,6 +1871,34 @@ 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)

{
@@ -1885,6 +1941,7 @@ 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,

};