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tcmu: reconfigure netlink attr changes
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1. TCMU_ATTR_TYPE is too generic when it describes only the
reconfiguration type, so rename to TCMU_ATTR_RECONFIG_TYPE.

2. Only return the reconfig type when it is a
TCMU_CMD_RECONFIG_DEVICE command.

3. CONFIG_* type is not needed. We can pass the value along with an
ATTR to userspace, so it does not need to read sysfs/configfs.

4. Fix leak in tcmu_dev_path_store and rename to dev_config to
reflect it is more than just a path that can be changed.

6. Don't update kernel struct value if netlink sending fails.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: "Bryant G. Ly" <bryantly@linux.vnet.ibm.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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Mike Christie authored and Nicholas Bellinger committed Jul 7, 2017
1 parent 5f57252 commit 2d76443
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Showing 2 changed files with 48 additions and 37 deletions.
73 changes: 44 additions & 29 deletions drivers/target/target_core_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1177,7 +1177,8 @@ static int tcmu_release(struct uio_info *info, struct inode *inode)
}

static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name,
int minor, int type)
int minor, int reconfig_attr,
const void *reconfig_data)
{
struct sk_buff *skb;
void *msg_header;
Expand All @@ -1199,9 +1200,27 @@ static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name,
if (ret < 0)
goto free_skb;

ret = nla_put_u32(skb, TCMU_ATTR_TYPE, type);
if (ret < 0)
goto free_skb;
if (cmd == TCMU_CMD_RECONFIG_DEVICE) {
switch (reconfig_attr) {
case TCMU_ATTR_DEV_CFG:
ret = nla_put_string(skb, reconfig_attr, reconfig_data);
break;
case TCMU_ATTR_DEV_SIZE:
ret = nla_put_u64_64bit(skb, reconfig_attr,
*((u64 *)reconfig_data),
TCMU_ATTR_PAD);
break;
case TCMU_ATTR_WRITECACHE:
ret = nla_put_u8(skb, reconfig_attr,
*((u8 *)reconfig_data));
break;
default:
BUG();
}

if (ret < 0)
goto free_skb;
}

genlmsg_end(skb, msg_header);

Expand Down Expand Up @@ -1306,7 +1325,7 @@ static int tcmu_configure_device(struct se_device *dev)
kref_get(&udev->kref);

ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
udev->uio_info.uio_dev->minor, NO_RECONFIG);
udev->uio_info.uio_dev->minor, 0, NULL);
if (ret)
goto err_netlink;

Expand Down Expand Up @@ -1388,7 +1407,7 @@ static void tcmu_free_device(struct se_device *dev)

if (tcmu_dev_configured(udev)) {
tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
udev->uio_info.uio_dev->minor, NO_RECONFIG);
udev->uio_info.uio_dev->minor, 0, NULL);

uio_unregister_device(&udev->uio_info);
}
Expand Down Expand Up @@ -1553,7 +1572,7 @@ static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *pag
}
CONFIGFS_ATTR(tcmu_, cmd_time_out);

static ssize_t tcmu_dev_path_show(struct config_item *item, char *page)
static ssize_t tcmu_dev_config_show(struct config_item *item, char *page)
{
struct se_dev_attrib *da = container_of(to_config_group(item),
struct se_dev_attrib, da_group);
Expand All @@ -1562,37 +1581,34 @@ static ssize_t tcmu_dev_path_show(struct config_item *item, char *page)
return snprintf(page, PAGE_SIZE, "%s\n", udev->dev_config);
}

static ssize_t tcmu_dev_path_store(struct config_item *item, const char *page,
size_t count)
static ssize_t tcmu_dev_config_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);
char *copy = NULL;
int ret;
int ret, len;

copy = kstrdup(page, GFP_KERNEL);
if (!copy) {
kfree(copy);
len = strlen(page);
if (!len || len > TCMU_CONFIG_LEN - 1)
return -EINVAL;
}
strlcpy(udev->dev_config, copy, TCMU_CONFIG_LEN);

/* Check if device has been configured before */
if (tcmu_dev_configured(udev)) {
ret = tcmu_netlink_event(TCMU_CMD_RECONFIG_DEVICE,
udev->uio_info.name,
udev->uio_info.uio_dev->minor,
CONFIG_PATH);
TCMU_ATTR_DEV_CFG, page);
if (ret) {
pr_err("Unable to reconfigure device\n");
return ret;
}
}
strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);

return count;
}
CONFIGFS_ATTR(tcmu_, dev_path);
CONFIGFS_ATTR(tcmu_, dev_config);

static ssize_t tcmu_dev_size_show(struct config_item *item, char *page)
{
Expand All @@ -1609,26 +1625,25 @@ static ssize_t tcmu_dev_size_store(struct config_item *item, const 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);
unsigned long val;
u64 val;
int ret;

ret = kstrtoul(page, 0, &val);
ret = kstrtou64(page, 0, &val);
if (ret < 0)
return ret;
udev->dev_size = val;

/* Check if device has been configured before */
if (tcmu_dev_configured(udev)) {
ret = tcmu_netlink_event(TCMU_CMD_RECONFIG_DEVICE,
udev->uio_info.name,
udev->uio_info.uio_dev->minor,
CONFIG_SIZE);
TCMU_ATTR_DEV_SIZE, &val);
if (ret) {
pr_err("Unable to reconfigure device\n");
return ret;
}
}

udev->dev_size = val;
return count;
}
CONFIGFS_ATTR(tcmu_, dev_size);
Expand All @@ -1648,33 +1663,33 @@ static ssize_t tcmu_emulate_write_cache_store(struct config_item *item,
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);
int val;
u8 val;
int ret;

ret = kstrtouint(page, 0, &val);
ret = kstrtou8(page, 0, &val);
if (ret < 0)
return ret;

da->emulate_write_cache = val;

/* Check if device has been configured before */
if (tcmu_dev_configured(udev)) {
ret = tcmu_netlink_event(TCMU_CMD_RECONFIG_DEVICE,
udev->uio_info.name,
udev->uio_info.uio_dev->minor,
CONFIG_WRITECACHE);
TCMU_ATTR_WRITECACHE, &val);
if (ret) {
pr_err("Unable to reconfigure device\n");
return ret;
}
}

da->emulate_write_cache = val;
return count;
}
CONFIGFS_ATTR(tcmu_, emulate_write_cache);

static struct configfs_attribute *tcmu_attrib_attrs[] = {
&tcmu_attr_cmd_time_out,
&tcmu_attr_dev_path,
&tcmu_attr_dev_config,
&tcmu_attr_dev_size,
&tcmu_attr_emulate_write_cache,
NULL,
Expand Down
12 changes: 4 additions & 8 deletions include/uapi/linux/target_core_user.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -139,16 +139,12 @@ enum tcmu_genl_attr {
TCMU_ATTR_UNSPEC,
TCMU_ATTR_DEVICE,
TCMU_ATTR_MINOR,
TCMU_ATTR_TYPE,
TCMU_ATTR_PAD,
TCMU_ATTR_DEV_CFG,
TCMU_ATTR_DEV_SIZE,
TCMU_ATTR_WRITECACHE,
__TCMU_ATTR_MAX,
};
#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)

enum tcmu_reconfig_types {
NO_RECONFIG,
CONFIG_PATH,
CONFIG_SIZE,
CONFIG_WRITECACHE,
};

#endif

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