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target: Add netlink command reply supported option for each device

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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@gmail.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Kenjiro Nakayama 2017-09-13 14:01:22 +09:00 committed by Nicholas Bellinger
parent b5ab697c62
commit b849b45675
1 changed files with 58 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

59
drivers/target/target_core_user.c
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@ -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,
};