4 files changed, 87 insertions, 1 deletions

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-rndis b/Documentation/ABI/testing/configfs-usb-gadget-rndis
new file mode 100644
index 000000000000..ff127ddb807c
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-rndis
@@ -0,0 +1,14 @@
+What:           /config/usb-gadget/gadget/functions/rndis.name
+Date:           May 2013
+KenelVersion:   3.11
+Description:
+                The attributes:
+
+                ifname          - network device interface name associated with
+                                this function instance
+                qmult           - queue length multiplier for high and
+                                super speed
+                host_addr       - MAC address of host's end of this
+                                Ethernet over USB link
+                dev_addr        - MAC address of device's end of this
+                                Ethernet over USB link
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 19373a300ec4..b6cd4bd74cb2 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -560,6 +560,22 @@ config USB_CONFIGFS_ECM_SUBSET
           On hardware that can't implement the full protocol,
           a simple CDC subset is used, placing fewer demands on USB.
 
+config USB_CONFIGFS_RNDIS
+        bool "RNDIS"
+        depends on USB_CONFIGFS
+        depends on NET
+        select USB_U_ETHER
+        select USB_F_RNDIS
+        help
+           Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol,
+           and Microsoft provides redistributable binary RNDIS drivers for
+           older versions of Windows.
+
+           To make MS-Windows work with this, use Documentation/usb/linux.inf
+           as the "driver info file".  For versions of MS-Windows older than
+           XP, you'll need to download drivers from Microsoft's website; a URL
+           is given in comments found in that info file.
+
 config USB_CONFIGFS_EEM
         bool "Ethernet Emulation Model (EEM)"
         depends on USB_CONFIGFS
diff --git a/drivers/usb/gadget/f_rndis.c b/drivers/usb/gadget/f_rndis.c
index 4045ca24e7c8..191df35ae69d 100644
--- a/drivers/usb/gadget/f_rndis.c
+++ b/drivers/usb/gadget/f_rndis.c
@@ -24,6 +24,7 @@
 #include <linux/atomic.h>
 
 #include "u_ether.h"
+#include "u_ether_configfs.h"
 #include "u_rndis.h"
 #include "rndis.h"
 
@@ -903,6 +904,41 @@ void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net)
 }
 EXPORT_SYMBOL(rndis_borrow_net);
 
+static inline struct f_rndis_opts *to_f_rndis_opts(struct config_item *item)
+{
+        return container_of(to_config_group(item), struct f_rndis_opts,
+                            func_inst.group);
+}
+
+/* f_rndis_item_ops */
+USB_ETHERNET_CONFIGFS_ITEM(rndis);
+
+/* f_rndis_opts_dev_addr */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(rndis);
+
+/* f_rndis_opts_host_addr */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(rndis);
+
+/* f_rndis_opts_qmult */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(rndis);
+
+/* f_rndis_opts_ifname */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(rndis);
+
+static struct configfs_attribute *rndis_attrs[] = {
+        &f_rndis_opts_dev_addr.attr,
+        &f_rndis_opts_host_addr.attr,
+        &f_rndis_opts_qmult.attr,
+        &f_rndis_opts_ifname.attr,
+        NULL,
+};
+
+static struct config_item_type rndis_func_type = {
+        .ct_item_ops    = &rndis_item_ops,
+        .ct_attrs       = rndis_attrs,
+        .ct_owner       = THIS_MODULE,
+};
+
 static void rndis_free_inst(struct usb_function_instance *f)
 {
         struct f_rndis_opts *opts;
@@ -924,22 +960,30 @@ static struct usb_function_instance *rndis_alloc_inst(void)
         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
         if (!opts)
                 return ERR_PTR(-ENOMEM);
-
+        mutex_init(&opts->lock);
         opts->func_inst.free_func_inst = rndis_free_inst;
         opts->net = gether_setup_default();
         if (IS_ERR(opts->net))
                 return ERR_CAST(opts->net);
 
+        config_group_init_type_name(&opts->func_inst.group, "",
+                                    &rndis_func_type);
+
         return &opts->func_inst;
 }
 
 static void rndis_free(struct usb_function *f)
 {
         struct f_rndis *rndis;
+        struct f_rndis_opts *opts;
 
         rndis = func_to_rndis(f);
         rndis_deregister(rndis->config);
+        opts = container_of(f->fi, struct f_rndis_opts, func_inst);
         kfree(rndis);
+        mutex_lock(&opts->lock);
+        opts->refcnt--;
+        mutex_unlock(&opts->lock);
 }
 
 static void rndis_unbind(struct usb_configuration *c, struct usb_function *f)
@@ -964,12 +1008,15 @@ static struct usb_function *rndis_alloc(struct usb_function_instance *fi)
                 return ERR_PTR(-ENOMEM);
 
         opts = container_of(fi, struct f_rndis_opts, func_inst);
+        mutex_lock(&opts->lock);
+        opts->refcnt++;
 
         gether_get_host_addr_u8(opts->net, rndis->ethaddr);
         rndis->vendorID = opts->vendor_id;
         rndis->manufacturer = opts->manufacturer;
 
         rndis->port.ioport = netdev_priv(opts->net);
+        mutex_unlock(&opts->lock);
         /* RNDIS activates when the host changes this filter */
         rndis->port.cdc_filter = 0;
 
diff --git a/drivers/usb/gadget/u_rndis.h b/drivers/usb/gadget/u_rndis.h
index d274df56ce75..c62ba82e9600 100644
--- a/drivers/usb/gadget/u_rndis.h
+++ b/drivers/usb/gadget/u_rndis.h
@@ -25,6 +25,15 @@ struct f_rndis_opts {
         struct net_device               *net;
         bool                            bound;
         bool                            borrowed_net;
+
+        /*
+         * Read/write access to configfs attributes is handled by configfs.
+         *
+         * This is to protect the data from concurrent access by read/write
+         * and create symlink/remove symlink.
+         */
+        struct mutex                    lock;
+        int                             refcnt;
 };
 
 void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net);