usb: gadget: printer: allocate printer_dev instances dynamically

With all the obstacles removed it is possible to allow more than one
instance of the printer function. Since the function requires allocating
character device region, a maximum number of allowed instances is defined.
Such an approach is used in f_acm and in f_hid.
With multiple instances it does not make sense to depend on a
lock_printer_io member of a dynamically allocated (and destroyed) struct
printer_dev to clean up after all instances of the printer function.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/gadget/legacy/printer.c b/drivers/usb/gadget/legacy/printer.c
index c059af1aa454fb9c8ec20d520fe0f938f6fc9f97..d1f85f81975fccd0f47f39d69571f2775640676a 100644 (file)
--- a/drivers/usb/gadget/legacy/printer.c
+++ b/drivers/usb/gadget/legacy/printer.c
@@ -51,11 +51,12 @@ USB_GADGET_COMPOSITE_OPTIONS();
 #define GET_PORT_STATUS                1
 #define SOFT_RESET             2
 
+#define PRINTER_MINORS         4
+
 static const char shortname [] = "printer";
 static const char driver_desc [] = DRIVER_DESC;
 
-static dev_t g_printer_devno;
-
+static int major, minors;
 static struct class *usb_gadget_class;
 
 /*-------------------------------------------------------------------------*/
@@ -84,6 +85,7 @@ struct printer_dev {
        u8                      *current_rx_buf;
        u8                      printer_status;
        u8                      reset_printer;
+       int                     minor;
        struct cdev             printer_cdev;
        u8                      printer_cdev_open;
        wait_queue_head_t       wait;
@@ -97,8 +99,6 @@ static inline struct printer_dev *func_to_printer(struct usb_function *f)
        return container_of(f, struct printer_dev, function);
 }
 
-static struct printer_dev usb_printer_gadget;
-
 /*-------------------------------------------------------------------------*/
 
 /* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
@@ -1096,6 +1096,7 @@ static int __init printer_func_bind(struct usb_configuration *c,
        struct usb_ep *in_ep;
        struct usb_ep *out_ep = NULL;
        struct usb_request *req;
+       dev_t devt;
        int id;
        int ret;
        u32 i;
@@ -1153,8 +1154,9 @@ autoconf_fail:
        }
 
        /* Setup the sysfs files for the printer gadget. */
-       pdev = device_create(usb_gadget_class, NULL, g_printer_devno,
-                                 NULL, "g_printer");
+       devt = MKDEV(major, dev->minor);
+       pdev = device_create(usb_gadget_class, NULL, devt,
+                                 NULL, "g_printer%d", dev->minor);
        if (IS_ERR(pdev)) {
                ERROR(dev, "Failed to create device: g_printer\n");
                ret = PTR_ERR(pdev);
@@ -1167,7 +1169,7 @@ autoconf_fail:
         */
        cdev_init(&dev->printer_cdev, &printer_io_operations);
        dev->printer_cdev.owner = THIS_MODULE;
-       ret = cdev_add(&dev->printer_cdev, g_printer_devno, 1);
+       ret = cdev_add(&dev->printer_cdev, devt, 1);
        if (ret) {
                ERROR(dev, "Failed to open char device\n");
                goto fail_cdev_add;
@@ -1176,7 +1178,7 @@ autoconf_fail:
        return 0;
 
 fail_cdev_add:
-       device_destroy(usb_gadget_class, g_printer_devno);
+       device_destroy(usb_gadget_class, devt);
 
 fail_rx_reqs:
        while (!list_empty(&dev->rx_reqs)) {
@@ -1204,7 +1206,7 @@ static void printer_func_unbind(struct usb_configuration *c,
 
        dev = func_to_printer(f);
 
-       device_destroy(usb_gadget_class, g_printer_devno);
+       device_destroy(usb_gadget_class, MKDEV(major, dev->minor));
 
        /* Remove Character Device */
        cdev_del(&dev->printer_cdev);
@@ -1238,6 +1240,7 @@ static void printer_func_unbind(struct usb_configuration *c,
                printer_req_free(dev->out_ep, req);
        }
        usb_free_all_descriptors(f);
+       kfree(dev);
 }
 
 static int printer_func_set_alt(struct usb_function *f,
@@ -1271,14 +1274,21 @@ static struct usb_configuration printer_cfg_driver = {
 };
 
 static int f_printer_bind_config(struct usb_configuration *c, char *pnp_str,
-                                char *pnp_string, unsigned q_len)
+                                char *pnp_string, unsigned q_len, int minor)
 {
        struct printer_dev      *dev;
        int                     status = -ENOMEM;
        size_t                  len;
 
-       dev = &usb_printer_gadget;
+       if (minor >= minors)
+               return -ENOENT;
+
+       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+       if (!dev)
+               return -ENOMEM;
+
        dev->pnp_string = pnp_string;
+       dev->minor = minor;
 
        dev->function.name = shortname;
        dev->function.bind = printer_func_bind;
@@ -1315,8 +1325,10 @@ static int f_printer_bind_config(struct usb_configuration *c, char *pnp_str,
        dev->q_len = q_len;
 
        status = usb_add_function(c, &dev->function);
-       if (status)
+       if (status) {
+               kfree(dev);
                return status;
+       }
        INFO(dev, "%s, version: " DRIVER_VERSION "\n", driver_desc);
        return 0;
 }
@@ -1335,43 +1347,51 @@ static int __init printer_do_config(struct usb_configuration *c)
                printer_cfg_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
        }
 
-       return f_printer_bind_config(c, iPNPstring, pnp_string, QLEN);
-
+       return f_printer_bind_config(c, iPNPstring, pnp_string, QLEN, 0);
 }
 
-static int gprinter_setup(void)
+static int gprinter_setup(int count)
 {
        int status;
+       dev_t devt;
 
        usb_gadget_class = class_create(THIS_MODULE, "usb_printer_gadget");
        if (IS_ERR(usb_gadget_class)) {
                status = PTR_ERR(usb_gadget_class);
+               usb_gadget_class = NULL;
                pr_err("unable to create usb_gadget class %d\n", status);
                return status;
        }
 
-       status = alloc_chrdev_region(&g_printer_devno, 0, 1,
-                       "USB printer gadget");
+       status = alloc_chrdev_region(&devt, 0, count, "USB printer gadget");
        if (status) {
                pr_err("alloc_chrdev_region %d\n", status);
                class_destroy(usb_gadget_class);
+               usb_gadget_class = NULL;
+               return status;
        }
 
+       major = MAJOR(devt);
+       minors = count;
+
        return status;
 }
 
-/* must be called with struct printer_dev's lock_printer_io held */
 static void gprinter_cleanup(void)
 {
-       unregister_chrdev_region(g_printer_devno, 1);
+       if (major) {
+               unregister_chrdev_region(MKDEV(major, 0), minors);
+               major = minors = 0;
+       }
        class_destroy(usb_gadget_class);
+       usb_gadget_class = NULL;
 }
 
 static int __init printer_bind(struct usb_composite_dev *cdev)
 {
        int ret;
 
-       ret = gprinter_setup();
+       ret = gprinter_setup(PRINTER_MINORS);
        if (ret)
                return ret;
 
@@ -1418,9 +1438,7 @@ module_init(init);
 static void __exit
 cleanup(void)
 {
-       mutex_lock(&usb_printer_gadget.lock_printer_io);
        usb_composite_unregister(&printer_driver);
-       mutex_unlock(&usb_printer_gadget.lock_printer_io);
 }
 module_exit(cleanup);