usb: gadget: printer: Remove pnp_string static buffer

pnp string is usually much shorter than 1k so let's stop wasting 1k of
memory for its buffer and make it dynamically alocated.
This also removes 1k len limitation for pnp_string and
adds a new line after string content if required.

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

1 files changed, 43 insertions, 14 deletions

diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c
index 8054da9276dd..8df244fc9d80 100644
--- a/drivers/usb/gadget/function/f_printer.c
+++ b/drivers/usb/gadget/function/f_printer.c
@@ -49,7 +49,6 @@
 
 #include "u_printer.h"
 
-#define PNP_STRING_LEN		1024
 #define PRINTER_MINORS		4
 #define GET_DEVICE_ID		0
 #define GET_PORT_STATUS		1
@@ -907,8 +906,7 @@ static bool gprinter_req_match(struct usb_function *f,
 	switch (ctrl->bRequest) {
 	case GET_DEVICE_ID:
 		w_index >>= 8;
-		if (w_length <= PNP_STRING_LEN &&
-		    (USB_DIR_IN & ctrl->bRequestType))
+		if (USB_DIR_IN & ctrl->bRequestType)
 			break;
 		return false;
 	case GET_PORT_STATUS:
@@ -937,6 +935,7 @@ static int printer_func_setup(struct usb_function *f,
 	struct printer_dev *dev = func_to_printer(f);
 	struct usb_composite_dev *cdev = f->config->cdev;
 	struct usb_request	*req = cdev->req;
+	u8			*buf = req->buf;
 	int			value = -EOPNOTSUPP;
 	u16			wIndex = le16_to_cpu(ctrl->wIndex);
 	u16			wValue = le16_to_cpu(ctrl->wValue);
@@ -953,10 +952,16 @@ static int printer_func_setup(struct usb_function *f,
 			if ((wIndex>>8) != dev->interface)
 				break;
 
-			value = (dev->pnp_string[0] << 8) | dev->pnp_string[1];
-			memcpy(req->buf, dev->pnp_string, value);
+			if (!dev->pnp_string) {
+				value = 0;
+				break;
+			}
+			value = strlen(dev->pnp_string);
+			buf[0] = (value >> 8) & 0xFF;
+			buf[1] = value & 0xFF;
+			memcpy(buf + 2, dev->pnp_string, value);
 			DBG(dev, "1284 PNP String: %x %s\n", value,
-					&dev->pnp_string[2]);
+			    dev->pnp_string);
 			break;
 
 		case GET_PORT_STATUS: /* Get Port Status */
@@ -964,7 +969,7 @@ static int printer_func_setup(struct usb_function *f,
 			if (wIndex != dev->interface)
 				break;
 
-			*(u8 *)req->buf = dev->printer_status;
+			buf[0] = dev->printer_status;
 			value = min_t(u16, wLength, 1);
 			break;
 
@@ -1157,10 +1162,21 @@ static ssize_t f_printer_opts_pnp_string_show(struct config_item *item,
 					      char *page)
 {
 	struct f_printer_opts *opts = to_f_printer_opts(item);
-	int result;
+	int result = 0;
 
 	mutex_lock(&opts->lock);
-	result = strlcpy(page, opts->pnp_string + 2, PNP_STRING_LEN - 2);
+	if (!opts->pnp_string)
+		goto unlock;
+
+	result = strlcpy(page, opts->pnp_string, PAGE_SIZE);
+	if (result >= PAGE_SIZE) {
+		result = PAGE_SIZE;
+	} else if (page[result - 1] != '\n' && result + 1 < PAGE_SIZE) {
+		page[result++] = '\n';
+		page[result] = '\0';
+	}
+
+unlock:
 	mutex_unlock(&opts->lock);
 
 	return result;
@@ -1170,13 +1186,24 @@ static ssize_t f_printer_opts_pnp_string_store(struct config_item *item,
 					       const char *page, size_t len)
 {
 	struct f_printer_opts *opts = to_f_printer_opts(item);
-	int result, l;
+	char *new_pnp;
+	int result;
 
 	mutex_lock(&opts->lock);
-	result = strlcpy(opts->pnp_string + 2, page, PNP_STRING_LEN - 2);
-	l = strlen(opts->pnp_string + 2) + 2;
-	opts->pnp_string[0] = (l >> 8) & 0xFF;
-	opts->pnp_string[1] = l & 0xFF;
+
+	new_pnp = kstrndup(page, len, GFP_KERNEL);
+	if (!new_pnp) {
+		result = -ENOMEM;
+		goto unlock;
+	}
+
+	if (opts->pnp_string_allocated)
+		kfree(opts->pnp_string);
+
+	opts->pnp_string_allocated = true;
+	opts->pnp_string = new_pnp;
+	result = len;
+unlock:
 	mutex_unlock(&opts->lock);
 
 	return result;
@@ -1270,6 +1297,8 @@ static void gprinter_free_inst(struct usb_function_instance *f)
 
 	mutex_unlock(&printer_ida_lock);
 
+	if (opts->pnp_string_allocated)
+		kfree(opts->pnp_string);
 	kfree(opts);
 }