Merge tag 'usb-for-v3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-next

Felipe writes:

usb: patches for v3.13

Final conversions to configfs for mass storage, acm_ms, and
multi gadgets.

MUSB should now work out of the box on AM335x-based boards
(beagle bone white and black) with DMA thanks to Sebastian's
work.

We can now enable VERBOSE_DEBUG on builds of drivers/usb/gadget/
by selecting CONFIG_USB_GADGET_VERBOSE.

s3c-hsotg got quite a few non-critical fixes but also learned
a few new tricks (isochronous transfers, multi count support).

The Marvel USB3 Controller driver got a memory leak fix.

devm_usb_get_phy() learned not to return NULL, ever.

Other than these patches, we have the usual set of cleanups
ranging from removal of unnecessary *_set_drvdata() to using
SIMPLE_DEV_PM_OPS.

Signed-of-by: Felipe Balbi <balbi@ti.com>

44 files changed, 2885 insertions, 1162 deletions

diff --git a/drivers/phy/phy-twl4030-usb.c b/drivers/phy/phy-twl4030-usb.c
index e0212d80c75c..daf65e68aaab 100644
--- a/drivers/phy/phy-twl4030-usb.c
+++ b/drivers/phy/phy-twl4030-usb.c
@@ -724,6 +724,8 @@ static int twl4030_usb_probe(struct platform_device *pdev)
 	if (device_create_file(&pdev->dev, &dev_attr_vbus))
 		dev_warn(&pdev->dev, "could not create sysfs file\n");
 
+	ATOMIC_INIT_NOTIFIER_HEAD(&twl->phy.notifier);
+
 	/* Our job is to use irqs and status from the power module
 	 * to keep the transceiver disabled when nothing's connected.
 	 *
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 474162e9d01d..74f9cf02da07 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -584,7 +584,7 @@ static int dwc3_remove(struct platform_device *pdev)
 	usb_phy_set_suspend(dwc->usb2_phy, 1);
 	usb_phy_set_suspend(dwc->usb3_phy, 1);
 
-	pm_runtime_put(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
 	dwc3_debugfs_exit(dwc);
@@ -691,7 +691,6 @@ static int dwc3_resume(struct device *dev)
 
 	usb_phy_init(dwc->usb3_phy);
 	usb_phy_init(dwc->usb2_phy);
-	msleep(100);
 
 	spin_lock_irqsave(&dwc->lock, flags);
 
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 48cddf3cd6b8..a91e6422f930 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -58,6 +58,20 @@ config USB_GADGET_DEBUG
 	   trying to track down.  Never enable these messages for a
 	   production build.
 
+config USB_GADGET_VERBOSE
+	bool "Verbose debugging Messages (DEVELOPMENT)"
+	depends on USB_GADGET_DEBUG
+	help
+	   Many controller and gadget drivers will print verbose debugging
+	   messages if you use this option to ask for those messages.
+
+	   Avoid enabling these messages, even if you're actively
+	   debugging such a driver.  Many drivers will emit so many
+	   messages that the driver timings are affected, which will
+	   either create new failure modes or remove the one you're
+	   trying to track down.  Never enable these messages for a
+	   production build.
+
 config USB_GADGET_DEBUG_FILES
 	boolean "Debugging information files (DEVELOPMENT)"
 	depends on PROC_FS
@@ -525,6 +539,9 @@ config USB_F_SUBSET
 config USB_F_RNDIS
 	tristate
 
+config USB_F_MASS_STORAGE
+	tristate
+
 choice
 	tristate "USB Gadget Drivers"
 	default USB_ETH
@@ -662,6 +679,16 @@ config USB_CONFIGFS_PHONET
 	help
 	  The Phonet protocol implementation for USB device.
 
+config USB_CONFIGFS_MASS_STORAGE
+	boolean "Mass storage"
+	depends on USB_CONFIGFS
+	select USB_F_MASS_STORAGE
+	help
+	  The Mass Storage Gadget acts as a USB Mass Storage disk drive.
+	  As its storage repository it can use a regular file or a block
+	  device (in much the same way as the "loop" device driver),
+	  specified as a module parameter or sysfs option.
+
 config USB_ZERO
 	tristate "Gadget Zero (DEVELOPMENT)"
 	select USB_LIBCOMPOSITE
@@ -878,6 +905,7 @@ config USB_MASS_STORAGE
 	tristate "Mass Storage Gadget"
 	depends on BLOCK
 	select USB_LIBCOMPOSITE
+	select USB_F_MASS_STORAGE
 	help
 	  The Mass Storage Gadget acts as a USB Mass Storage disk drive.
 	  As its storage repository it can use a regular file or a block
@@ -1001,6 +1029,7 @@ config USB_G_ACM_MS
 	select USB_LIBCOMPOSITE
 	select USB_U_SERIAL
 	select USB_F_ACM
+	select USB_F_MASS_STORAGE
 	help
 	  This driver provides two functions in one configuration:
 	  a mass storage, and a CDC ACM (serial port) link.
@@ -1015,8 +1044,8 @@ config USB_G_MULTI
 	select USB_LIBCOMPOSITE
 	select USB_U_SERIAL
 	select USB_U_ETHER
-	select USB_U_RNDIS
 	select USB_F_ACM
+	select USB_F_MASS_STORAGE
 	help
 	  The Multifunction Composite Gadget provides Ethernet (RNDIS
 	  and/or CDC Ethernet), mass storage and ACM serial link
@@ -1035,6 +1064,8 @@ config USB_G_MULTI
 config USB_G_MULTI_RNDIS
 	bool "RNDIS + CDC Serial + Storage configuration"
 	depends on USB_G_MULTI
+	select USB_U_RNDIS
+	select USB_F_RNDIS
 	default y
 	help
 	  This option enables a configuration with RNDIS, CDC Serial and
@@ -1048,6 +1079,7 @@ config USB_G_MULTI_CDC
 	bool "CDC Ethernet + CDC Serial + Storage configuration"
 	depends on USB_G_MULTI
 	default n
+	select USB_F_ECM
 	help
 	  This option enables a configuration with CDC Ethernet (ECM), CDC
 	  Serial and Mass Storage functions available in the Multifunction
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 386db9daf1d9..f1af39603d4d 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -1,7 +1,8 @@
 #
 # USB peripheral controller drivers
 #
-ccflags-$(CONFIG_USB_GADGET_DEBUG) := -DDEBUG
+ccflags-$(CONFIG_USB_GADGET_DEBUG)	:= -DDEBUG
+ccflags-$(CONFIG_USB_GADGET_VERBOSE)	+= -DVERBOSE_DEBUG
 
 obj-$(CONFIG_USB_GADGET)	+= udc-core.o
 obj-$(CONFIG_USB_LIBCOMPOSITE)	+= libcomposite.o
@@ -60,6 +61,8 @@ usb_f_ecm_subset-y		:= f_subset.o
 obj-$(CONFIG_USB_F_SUBSET)	+= usb_f_ecm_subset.o
 usb_f_rndis-y			:= f_rndis.o
 obj-$(CONFIG_USB_F_RNDIS)	+= usb_f_rndis.o
+usb_f_mass_storage-y		:= f_mass_storage.o storage_common.o
+obj-$(CONFIG_USB_F_MASS_STORAGE)+= usb_f_mass_storage.o
 
 #
 # USB gadget drivers
diff --git a/drivers/usb/gadget/acm_ms.c b/drivers/usb/gadget/acm_ms.c
index 4b947bb50f62..7bfa134fe0e3 100644
--- a/drivers/usb/gadget/acm_ms.c
+++ b/drivers/usb/gadget/acm_ms.c
@@ -31,16 +31,7 @@
 #define ACM_MS_VENDOR_NUM	0x1d6b	/* Linux Foundation */
 #define ACM_MS_PRODUCT_NUM	0x0106	/* Composite Gadget: ACM + MS*/
 
-/*-------------------------------------------------------------------------*/
-
-/*
- * Kbuild is not very cooperative with respect to linking separately
- * compiled library objects into one module.  So for now we won't use
- * separate compilation ... ensuring init/exit sections work to shrink
- * the runtime footprint, and giving us at least some parts of what
- * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
- */
-#include "f_mass_storage.c"
+#include "f_mass_storage.h"
 
 /*-------------------------------------------------------------------------*/
 USB_GADGET_COMPOSITE_OPTIONS();
@@ -104,18 +95,35 @@ static struct usb_gadget_strings *dev_strings[] = {
 /****************************** Configurations ******************************/
 
 static struct fsg_module_parameters fsg_mod_data = { .stall = 1 };
-FSG_MODULE_PARAMETERS(/* no prefix */, fsg_mod_data);
+#ifdef CONFIG_USB_GADGET_DEBUG_FILES
 
-static struct fsg_common fsg_common;
+static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
+
+#else
+
+/*
+ * Number of buffers we will use.
+ * 2 is usually enough for good buffering pipeline
+ */
+#define fsg_num_buffers	CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
+
+#endif /* CONFIG_USB_DEBUG */
+
+FSG_MODULE_PARAMETERS(/* no prefix */, fsg_mod_data);
 
 /*-------------------------------------------------------------------------*/
 static struct usb_function *f_acm;
 static struct usb_function_instance *f_acm_inst;
+
+static struct usb_function_instance *fi_msg;
+static struct usb_function *f_msg;
+
 /*
  * We _always_ have both ACM and mass storage functions.
  */
 static int __init acm_ms_do_config(struct usb_configuration *c)
 {
+	struct fsg_opts *opts;
 	int	status;
 
 	if (gadget_is_otg(c->cdev->gadget)) {
@@ -123,31 +131,37 @@ static int __init acm_ms_do_config(struct usb_configuration *c)
 		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 	}
 
-	f_acm_inst = usb_get_function_instance("acm");
-	if (IS_ERR(f_acm_inst))
-		return PTR_ERR(f_acm_inst);
+	opts = fsg_opts_from_func_inst(fi_msg);
 
 	f_acm = usb_get_function(f_acm_inst);
-	if (IS_ERR(f_acm)) {
-		status = PTR_ERR(f_acm);
-		goto err_func;
+	if (IS_ERR(f_acm))
+		return PTR_ERR(f_acm);
+
+	f_msg = usb_get_function(fi_msg);
+	if (IS_ERR(f_msg)) {
+		status = PTR_ERR(f_msg);
+		goto put_acm;
 	}
 
 	status = usb_add_function(c, f_acm);
 	if (status < 0)
-		goto err_conf;
+		goto put_msg;
 
-	status = fsg_bind_config(c->cdev, c, &fsg_common);
-	if (status < 0)
-		goto err_fsg;
+	status = fsg_common_run_thread(opts->common);
+	if (status)
+		goto remove_acm;
+
+	status = usb_add_function(c, f_msg);
+	if (status)
+		goto remove_acm;
 
 	return 0;
-err_fsg:
+remove_acm:
 	usb_remove_function(c, f_acm);
-err_conf:
+put_msg:
+	usb_put_function(f_msg);
+put_acm:
 	usb_put_function(f_acm);
-err_func:
-	usb_put_function_instance(f_acm_inst);
 	return status;
 }
 
@@ -163,45 +177,82 @@ static struct usb_configuration acm_ms_config_driver = {
 static int __init acm_ms_bind(struct usb_composite_dev *cdev)
 {
 	struct usb_gadget	*gadget = cdev->gadget;
+	struct fsg_opts		*opts;
+	struct fsg_config	config;
 	int			status;
-	void			*retp;
 
-	/* set up mass storage function */
-	retp = fsg_common_from_params(&fsg_common, cdev, &fsg_mod_data);
-	if (IS_ERR(retp)) {
-		status = PTR_ERR(retp);
-		return PTR_ERR(retp);
+	f_acm_inst = usb_get_function_instance("acm");
+	if (IS_ERR(f_acm_inst))
+		return PTR_ERR(f_acm_inst);
+
+	fi_msg = usb_get_function_instance("mass_storage");
+	if (IS_ERR(fi_msg)) {
+		status = PTR_ERR(fi_msg);
+		goto fail_get_msg;
 	}
 
+	/* set up mass storage function */
+	fsg_config_from_params(&config, &fsg_mod_data, fsg_num_buffers);
+	opts = fsg_opts_from_func_inst(fi_msg);
+
+	opts->no_configfs = true;
+	status = fsg_common_set_num_buffers(opts->common, fsg_num_buffers);
+	if (status)
+		goto fail;
+
+	status = fsg_common_set_nluns(opts->common, config.nluns);
+	if (status)
+		goto fail_set_nluns;
+
+	status = fsg_common_set_cdev(opts->common, cdev, config.can_stall);
+	if (status)
+		goto fail_set_cdev;
+
+	fsg_common_set_sysfs(opts->common, true);
+	status = fsg_common_create_luns(opts->common, &config);
+	if (status)
+		goto fail_set_cdev;
+
+	fsg_common_set_inquiry_string(opts->common, config.vendor_name,
+				      config.product_name);
 	/*
 	 * Allocate string descriptor numbers ... note that string
 	 * contents can be overridden by the composite_dev glue.
 	 */
 	status = usb_string_ids_tab(cdev, strings_dev);
 	if (status < 0)
-		goto fail1;
+		goto fail_string_ids;
 	device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
 	device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
 
 	/* register our configuration */
 	status = usb_add_config(cdev, &acm_ms_config_driver, acm_ms_do_config);
 	if (status < 0)
-		goto fail1;
+		goto fail_string_ids;
 
 	usb_composite_overwrite_options(cdev, &coverwrite);
 	dev_info(&gadget->dev, "%s, version: " DRIVER_VERSION "\n",
 			DRIVER_DESC);
-	fsg_common_put(&fsg_common);
 	return 0;
 
 	/* error recovery */
-fail1:
-	fsg_common_put(&fsg_common);
+fail_string_ids:
+	fsg_common_remove_luns(opts->common);
+fail_set_cdev:
+	fsg_common_free_luns(opts->common);
+fail_set_nluns:
+	fsg_common_free_buffers(opts->common);
+fail:
+	usb_put_function_instance(fi_msg);
+fail_get_msg:
+	usb_put_function_instance(f_acm_inst);
 	return status;
 }
 
 static int __exit acm_ms_unbind(struct usb_composite_dev *cdev)
 {
+	usb_put_function(f_msg);
+	usb_put_function_instance(fi_msg);
 	usb_put_function(f_acm);
 	usb_put_function_instance(f_acm_inst);
 	return 0;
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 8f0d6141e5e6..25885112fa35 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -557,7 +557,7 @@ static struct config_group *function_make(
 
 	fi = usb_get_function_instance(func_name);
 	if (IS_ERR(fi))
-		return ERR_PTR(PTR_ERR(fi));
+		return ERR_CAST(fi);
 
 	ret = config_item_set_name(&fi->group.cg_item, name);
 	if (ret) {
@@ -991,6 +991,14 @@ static struct configfs_subsystem gadget_subsys = {
 	.su_mutex = __MUTEX_INITIALIZER(gadget_subsys.su_mutex),
 };
 
+void unregister_gadget_item(struct config_item *item)
+{
+	struct gadget_info *gi = to_gadget_info(item);
+
+	unregister_gadget(gi);
+}
+EXPORT_SYMBOL(unregister_gadget_item);
+
 static int __init gadget_cfs_init(void)
 {
 	int ret;
diff --git a/drivers/usb/gadget/configfs.h b/drivers/usb/gadget/configfs.h
new file mode 100644
index 000000000000..a7b564a913d1
--- /dev/null
+++ b/drivers/usb/gadget/configfs.h
@@ -0,0 +1,6 @@
+#ifndef USB__GADGET__CONFIGFS__H
+#define USB__GADGET__CONFIGFS__H
+
+void unregister_gadget_item(struct config_item *item);
+
+#endif /*  USB__GADGET__CONFIGFS__H */
diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index a01d7d38c016..8fa8b1f771fb 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -213,12 +213,14 @@
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/freezer.h>
+#include <linux/module.h>
 
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb/composite.h>
 
 #include "gadget_chips.h"
+#include "configfs.h"
 
 
 /*------------------------------------------------------------------------*/
@@ -228,26 +230,30 @@
 
 static const char fsg_string_interface[] = "Mass Storage";
 
-#include "storage_common.c"
+#include "storage_common.h"
+#include "f_mass_storage.h"
 
+/* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
+static struct usb_string		fsg_strings[] = {
+	{FSG_STRING_INTERFACE,		fsg_string_interface},
+	{}
+};
+
+static struct usb_gadget_strings	fsg_stringtab = {
+	.language	= 0x0409,		/* en-us */
+	.strings	= fsg_strings,
+};
+
+static struct usb_gadget_strings *fsg_strings_array[] = {
+	&fsg_stringtab,
+	NULL,
+};
 
 /*-------------------------------------------------------------------------*/
 
 struct fsg_dev;
 struct fsg_common;
 
-/* FSF callback functions */
-struct fsg_operations {
-	/*
-	 * Callback function to call when thread exits.  If no
-	 * callback is set or it returns value lower then zero MSF
-	 * will force eject all LUNs it operates on (including those
-	 * marked as non-removable or with prevent_medium_removal flag
-	 * set).
-	 */
-	int (*thread_exits)(struct fsg_common *common);
-};
-
 /* Data shared by all the FSG instances. */
 struct fsg_common {
 	struct usb_gadget	*gadget;
@@ -268,13 +274,14 @@ struct fsg_common {
 	struct fsg_buffhd	*next_buffhd_to_fill;
 	struct fsg_buffhd	*next_buffhd_to_drain;
 	struct fsg_buffhd	*buffhds;
+	unsigned int		fsg_num_buffers;
 
 	int			cmnd_size;
 	u8			cmnd[MAX_COMMAND_SIZE];
 
 	unsigned int		nluns;
 	unsigned int		lun;
-	struct fsg_lun		*luns;
+	struct fsg_lun		**luns;
 	struct fsg_lun		*curlun;
 
 	unsigned int		bulk_out_maxpacket;
@@ -294,6 +301,7 @@ struct fsg_common {
 	unsigned int		short_packet_received:1;
 	unsigned int		bad_lun_okay:1;
 	unsigned int		running:1;
+	unsigned int		sysfs:1;
 
 	int			thread_wakeup_needed;
 	struct completion	thread_notifier;
@@ -313,27 +321,6 @@ struct fsg_common {
 	struct kref		ref;
 };
 
-struct fsg_config {
-	unsigned nluns;
-	struct fsg_lun_config {
-		const char *filename;
-		char ro;
-		char removable;
-		char cdrom;
-		char nofua;
-	} luns[FSG_MAX_LUNS];
-
-	/* Callback functions. */
-	const struct fsg_operations	*ops;
-	/* Gadget's private data. */
-	void			*private_data;
-
-	const char *vendor_name;		/*  8 characters or less */
-	const char *product_name;		/* 16 characters or less */
-
-	char			can_stall;
-};
-
 struct fsg_dev {
 	struct usb_function	function;
 	struct usb_gadget	*gadget;	/* Copy of cdev->gadget */
@@ -2172,7 +2159,7 @@ static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
 		common->data_dir = DATA_DIR_NONE;
 	common->lun = cbw->Lun;
 	if (common->lun < common->nluns)
-		common->curlun = &common->luns[common->lun];
+		common->curlun = common->luns[common->lun];
 	else
 		common->curlun = NULL;
 	common->tag = cbw->Tag;
@@ -2244,7 +2231,7 @@ reset:
 	if (common->fsg) {
 		fsg = common->fsg;
 
-		for (i = 0; i < fsg_num_buffers; ++i) {
+		for (i = 0; i < common->fsg_num_buffers; ++i) {
 			struct fsg_buffhd *bh = &common->buffhds[i];
 
 			if (bh->inreq) {
@@ -2303,7 +2290,7 @@ reset:
 	clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
 
 	/* Allocate the requests */
-	for (i = 0; i < fsg_num_buffers; ++i) {
+	for (i = 0; i < common->fsg_num_buffers; ++i) {
 		struct fsg_buffhd	*bh = &common->buffhds[i];
 
 		rc = alloc_request(common, fsg->bulk_in, &bh->inreq);
@@ -2320,7 +2307,9 @@ reset:
 
 	common->running = 1;
 	for (i = 0; i < common->nluns; ++i)
-		common->luns[i].unit_attention_data = SS_RESET_OCCURRED;
+		if (common->luns[i])
+			common->luns[i]->unit_attention_data =
+				SS_RESET_OCCURRED;
 	return rc;
 }
 
@@ -2372,7 +2361,7 @@ static void handle_exception(struct fsg_common *common)
 
 	/* Cancel all the pending transfers */
 	if (likely(common->fsg)) {
-		for (i = 0; i < fsg_num_buffers; ++i) {
+		for (i = 0; i < common->fsg_num_buffers; ++i) {
 			bh = &common->buffhds[i];
 			if (bh->inreq_busy)
 				usb_ep_dequeue(common->fsg->bulk_in, bh->inreq);
@@ -2384,7 +2373,7 @@ static void handle_exception(struct fsg_common *common)
 		/* Wait until everything is idle */
 		for (;;) {
 			int num_active = 0;
-			for (i = 0; i < fsg_num_buffers; ++i) {
+			for (i = 0; i < common->fsg_num_buffers; ++i) {
 				bh = &common->buffhds[i];
 				num_active += bh->inreq_busy + bh->outreq_busy;
 			}
@@ -2407,7 +2396,7 @@ static void handle_exception(struct fsg_common *common)
 	 */
 	spin_lock_irq(&common->lock);
 
-	for (i = 0; i < fsg_num_buffers; ++i) {
+	for (i = 0; i < common->fsg_num_buffers; ++i) {
 		bh = &common->buffhds[i];
 		bh->state = BUF_STATE_EMPTY;
 	}
@@ -2420,7 +2409,9 @@ static void handle_exception(struct fsg_common *common)
 		common->state = FSG_STATE_STATUS_PHASE;
 	else {
 		for (i = 0; i < common->nluns; ++i) {
-			curlun = &common->luns[i];
+			curlun = common->luns[i];
+			if (!curlun)
+				continue;
 			curlun->prevent_medium_removal = 0;
 			curlun->sense_data = SS_NO_SENSE;
 			curlun->unit_attention_data = SS_NO_SENSE;
@@ -2462,8 +2453,9 @@ static void handle_exception(struct fsg_common *common)
 		 * CONFIG_CHANGE cases.
 		 */
 		/* for (i = 0; i < common->nluns; ++i) */
-		/*	common->luns[i].unit_attention_data = */
-		/*		SS_RESET_OCCURRED;  */
+		/*	if (common->luns[i]) */
+		/*		common->luns[i]->unit_attention_data = */
+		/*			SS_RESET_OCCURRED;  */
 		break;
 
 	case FSG_STATE_CONFIG_CHANGE:
@@ -2559,12 +2551,13 @@ static int fsg_main_thread(void *common_)
 
 	if (!common->ops || !common->ops->thread_exits
 	 || common->ops->thread_exits(common) < 0) {
-		struct fsg_lun *curlun = common->luns;
+		struct fsg_lun **curlun_it = common->luns;
 		unsigned i = common->nluns;
 
 		down_write(&common->filesem);
-		for (; i--; ++curlun) {
-			if (!fsg_lun_is_open(curlun))
+		for (; i--; ++curlun_it) {
+			struct fsg_lun *curlun = *curlun_it;
+			if (!curlun || !fsg_lun_is_open(curlun))
 				continue;
 
 			fsg_lun_close(curlun);
@@ -2580,6 +2573,56 @@ static int fsg_main_thread(void *common_)
 
 /*************************** DEVICE ATTRIBUTES ***************************/
 
+static ssize_t ro_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
+
+	return fsg_show_ro(curlun, buf);
+}
+
+static ssize_t nofua_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
+
+	return fsg_show_nofua(curlun, buf);
+}
+
+static ssize_t file_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
+	struct rw_semaphore	*filesem = dev_get_drvdata(dev);
+
+	return fsg_show_file(curlun, filesem, buf);
+}
+
+static ssize_t ro_store(struct device *dev, struct device_attribute *attr,
+			const char *buf, size_t count)
+{
+	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
+	struct rw_semaphore	*filesem = dev_get_drvdata(dev);
+
+	return fsg_store_ro(curlun, filesem, buf, count);
+}
+
+static ssize_t nofua_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
+
+	return fsg_store_nofua(curlun, buf, count);
+}
+
+static ssize_t file_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
+	struct rw_semaphore	*filesem = dev_get_drvdata(dev);
+
+	return fsg_store_file(curlun, filesem, buf, count);
+}
+
 static DEVICE_ATTR_RW(ro);
 static DEVICE_ATTR_RW(nofua);
 static DEVICE_ATTR_RW(file);
@@ -2597,221 +2640,422 @@ static void fsg_lun_release(struct device *dev)
 	/* Nothing needs to be done */
 }
 
-static inline void fsg_common_get(struct fsg_common *common)
+void fsg_common_get(struct fsg_common *common)
 {
 	kref_get(&common->ref);
 }
+EXPORT_SYMBOL_GPL(fsg_common_get);
 
-static inline void fsg_common_put(struct fsg_common *common)
+void fsg_common_put(struct fsg_common *common)
 {
 	kref_put(&common->ref, fsg_common_release);
 }
+EXPORT_SYMBOL_GPL(fsg_common_put);
 
-static struct fsg_common *fsg_common_init(struct fsg_common *common,
-					  struct usb_composite_dev *cdev,
-					  struct fsg_config *cfg)
+/* check if fsg_num_buffers is within a valid range */
+static inline int fsg_num_buffers_validate(unsigned int fsg_num_buffers)
 {
-	struct usb_gadget *gadget = cdev->gadget;
-	struct fsg_buffhd *bh;
-	struct fsg_lun *curlun;
-	struct fsg_lun_config *lcfg;
-	int nluns, i, rc;
-	char *pathbuf;
-
-	rc = fsg_num_buffers_validate();
-	if (rc != 0)
-		return ERR_PTR(rc);
-