1 files changed, 924 insertions, 330 deletions

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index a01d7d38c016..a03ba2c83589 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);
-
-	/* Find out how many LUNs there should be */
-	nluns = cfg->nluns;
-	if (nluns < 1 || nluns > FSG_MAX_LUNS) {
-		dev_err(&gadget->dev, "invalid number of LUNs: %u\n", nluns);
-		return ERR_PTR(-EINVAL);
-	}
+	if (fsg_num_buffers >= 2 && fsg_num_buffers <= 4)
+		return 0;
+	pr_err("fsg_num_buffers %u is out of range (%d to %d)\n",
+	       fsg_num_buffers, 2, 4);
+	return -EINVAL;
+}
 
-	/* Allocate? */
+static struct fsg_common *fsg_common_setup(struct fsg_common *common)
+{
 	if (!common) {
-		common = kzalloc(sizeof *common, GFP_KERNEL);
+		common = kzalloc(sizeof(*common), GFP_KERNEL);
 		if (!common)
 			return ERR_PTR(-ENOMEM);
 		common->free_storage_on_release = 1;
 	} else {
-		memset(common, 0, sizeof *common);
 		common->free_storage_on_release = 0;
 	}
+	init_rwsem(&common->filesem);
+	spin_lock_init(&common->lock);
+	kref_init(&common->ref);
+	init_completion(&common->thread_notifier);
+	init_waitqueue_head(&common->fsg_wait);
+	common->state = FSG_STATE_TERMINATED;
 
-	common->buffhds = kcalloc(fsg_num_buffers,
-				  sizeof *(common->buffhds), GFP_KERNEL);
-	if (!common->buffhds) {
-		if (common->free_storage_on_release)
-			kfree(common);
-		return ERR_PTR(-ENOMEM);
+	return common;
+}
+
+void fsg_common_set_sysfs(struct fsg_common *common, bool sysfs)
+{
+	common->sysfs = sysfs;
+}
+EXPORT_SYMBOL_GPL(fsg_common_set_sysfs);
+
+static void _fsg_common_free_buffers(struct fsg_buffhd *buffhds, unsigned n)
+{
+	if (buffhds) {
+		struct fsg_buffhd *bh = buffhds;
+		while (n--) {
+			kfree(bh->buf);
+			++bh;
+		}
+		kfree(buffhds);
 	}
+}
 
-	common->ops = cfg->ops;
-	common->private_data = cfg->private_data;
+int fsg_common_set_num_buffers(struct fsg_common *common, unsigned int n)
+{
+	struct fsg_buffhd *bh, *buffhds;
+	int i, rc;
 
-	common->gadget = gadget;
-	common->ep0 = gadget->ep0;
-	common->ep0req = cdev->req;
-	common->cdev = cdev;
+	rc = fsg_num_buffers_validate(n);
+	if (rc != 0)
+		return rc;
+
+	buffhds = kcalloc(n, sizeof(*buffhds), GFP_KERNEL);
+	if (!buffhds)
+		return -ENOMEM;
 
-	/* Maybe allocate device-global string IDs, and patch descriptors */
-	if (fsg_strings[FSG_STRING_INTERFACE].id == 0) {
-		rc = usb_string_id(cdev);
-		if (unlikely(rc < 0))
+	/* Data buffers cyclic list */
+	bh = buffhds;
+	i = n;
+	goto buffhds_first_it;
+	do {
+		bh->next = bh + 1;
+		++bh;
+buffhds_first_it:
+		bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL);
+		if (unlikely(!bh->buf))
 			goto error_release;
-		fsg_strings[FSG_STRING_INTERFACE].id = rc;
-		fsg_intf_desc.iInterface = rc;
-	}
+	} while (--i);
+	bh->next = buffhds;
 
+	_fsg_common_free_buffers(common->buffhds, common->fsg_num_buffers);
+	common->fsg_num_buffers = n;
+	common->buffhds = buffhds;
+
+	return 0;
+
+error_release:
 	/*
-	 * Create the LUNs, open their backing files, and register the
-	 * LUN devices in sysfs.
+	 * "buf"s pointed to by heads after n - i are NULL
+	 * so releasing them won't hurt
 	 */
-	curlun = kcalloc(nluns, sizeof(*curlun), GFP_KERNEL);
-	if (unlikely(!curlun)) {
-		rc = -ENOMEM;
-		goto error_release;
+	_fsg_common_free_buffers(buffhds, n);
+
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(fsg_common_set_num_buffers);
+
+static inline void fsg_common_remove_sysfs(struct fsg_lun *lun)
+{
+	device_remove_file(&lun->dev, &dev_attr_nofua);
+	/*
+	 * device_remove_file() =>
+	 *
+	 * here the attr (e.g. dev_attr_ro) is only used to be passed to:
+	 *
+	 *	sysfs_remove_file() =>
+	 *
+	 *	here e.g. both dev_attr_ro_cdrom and dev_attr_ro are in
+	 *	the same namespace and
+	 *	from here only attr->name is passed to:
+	 *
+	 *		sysfs_hash_and_remove()
+	 *
+	 *		attr->name is the same for dev_attr_ro_cdrom and
+	 *		dev_attr_ro
+	 *		attr->name is the same for dev_attr_file and
+	 *		dev_attr_file_nonremovable
+	 *
+	 * so we don't differentiate between removing e.g. dev_attr_ro_cdrom
+	 * and dev_attr_ro
+	 */
+	device_remove_file(&lun->dev, &dev_attr_ro);
+	device_remove_file(&lun->dev, &dev_attr_file);
+}
+
+void fsg_common_remove_lun(struct fsg_lun *lun, bool sysfs)
+{
+	if (sysfs) {
+		fsg_common_remove_sysfs(lun);
+		device_unregister(&lun->dev);
 	}
-	common->luns = curlun;
+	fsg_lun_close(lun);
+	kfree(lun);
+}
+EXPORT_SYMBOL_GPL(fsg_common_remove_lun);
 
-	init_rwsem(&common->filesem);
+static void _fsg_common_remove_luns(struct fsg_common *common, int n)
+{
+	int i;
 
-	for (i = 0, lcfg = cfg->luns; i < nluns; ++i, ++curlun, ++lcfg) {
-		curlun->cdrom = !!lcfg->cdrom;
-		curlun->ro = lcfg->cdrom || lcfg->ro;
-		curlun->initially_ro = curlun->ro;
-		curlun->removable = lcfg->removable;
-		curlun->dev.release = fsg_lun_release;
-		curlun->dev.parent = &gadget->dev;
-		/* curlun->dev.driver = &fsg_driver.driver; XXX */
-		dev_set_drvdata(&curlun->dev, &common->filesem);
-		dev_set_name(&curlun->dev, "lun%d", i);
-
-		rc = device_register(&curlun->dev);
-		if (rc) {
-			INFO(common, "failed to register LUN%d: %d\n", i, rc);
-			common->nluns = i;
-			put_device(&curlun->dev);
-			goto error_release;
+	for (i = 0; i < n; ++i)
+		if (common->luns[i]) {
+			fsg_common_remove_lun(common->luns[i], common->sysfs);
+			common->luns[i] = NULL;
 		}
+}
+EXPORT_SYMBOL_GPL(fsg_common_remove_luns);
 
-		rc = device_create_file(&curlun->dev,
-					curlun->cdrom
-				      ? &dev_attr_ro_cdrom
-				      : &dev_attr_ro);
-		if (rc)
-			goto error_luns;
-		rc = device_create_file(&curlun->dev,
-					curlun->removable
-				      ? &dev_attr_file
-				      : &dev_attr_file_nonremovable);
-		if (rc)
-			goto error_luns;
-		rc = device_create_file(&curlun->dev, &dev_attr_nofua);
-		if (rc)
-			goto error_luns;
+void fsg_common_remove_luns(struct fsg_common *common)
+{
+	_fsg_common_remove_luns(common, common->nluns);
+}
 
-		if (lcfg->filename) {
-			rc = fsg_lun_open(curlun, lcfg->filename);
-			if (rc)
-				goto error_luns;
-		} else if (!curlun->removable) {
-			ERROR(common, "no file given for LUN%d\n", i);
-			rc = -EINVAL;
-			goto error_luns;
-		}
+void fsg_common_free_luns(struct fsg_common *common)
+{
+	fsg_common_remove_luns(common);
+	kfree(common->luns);
+	common->luns = NULL;
+}
+EXPORT_SYMBOL_GPL(fsg_common_free_luns);
+
+int fsg_common_set_nluns(struct fsg_common *common, int nluns)
+{
+	struct fsg_lun **curlun;
+
+	/* Find out how many LUNs there should be */
+	if (nluns < 1 || nluns > FSG_MAX_LUNS) {
+		pr_err("invalid number of LUNs: %u\n", nluns);
+		return -EINVAL;
 	}
+
+	curlun = kcalloc(nluns, sizeof(*curlun), GFP_KERNEL);
+	if (unlikely(!curlun))
+		return -ENOMEM;
+
+	if (common->luns)
+		fsg_common_free_luns(common);
+
+	common->luns = curlun;
 	common->nluns = nluns;
 
-	/* Data buffers cyclic list */
-	bh = common->buffhds;
-	i = fsg_num_buffers;
-	goto buffhds_first_it;
-	do {
-		bh->next = bh + 1;
-		++bh;
-buffhds_first_it:
-		bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL);
-		if (unlikely(!bh->buf)) {
-			rc = -ENOMEM;
-			goto error_release;
-		}
-	} while (--i);
-	bh->next = common->buffhds;
+	pr_info("Number of LUNs=%d\n", common->nluns);
 
-	/* Prepare inquiryString */
-	i = get_default_bcdDevice();
-	snprintf(common->inquiry_string, sizeof common->inquiry_string,
-		 "%-8s%-16s%04x", cfg->vendor_name ?: "Linux",
-		 /* Assume product name dependent on the first LUN */
-		 cfg->product_name ?: (common->luns->cdrom
-				     ? "File-CD Gadget"
-				     : "File-Stor Gadget"),
-		 i);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fsg_common_set_nluns);
+
+void fsg_common_set_ops(struct fsg_common *common,
+			const struct fsg_operations *ops)
+{
+	common->ops = ops;
+}
+EXPORT_SYMBOL_GPL(fsg_common_set_ops);
+
+void fsg_common_free_buffers(struct fsg_common *common)
+{
+	_fsg_common_free_buffers(common->buffhds, common->fsg_num_buffers);
+	common->buffhds = NULL;
+}
+EXPORT_SYMBOL_GPL(fsg_common_free_buffers);
+
+int fsg_common_set_cdev(struct fsg_common *common,
+			 struct usb_composite_dev *cdev, bool can_stall)
+{
+	struct usb_string *us;
+
+	common->gadget = cdev->gadget;
+	common->ep0 = cdev->gadget->ep0;
+	common->ep0req = cdev->req;
+	common->cdev = cdev;
+
+	us = usb_gstrings_attach(cdev, fsg_strings_array,
+				 ARRAY_SIZE(fsg_strings));
+	if (IS_ERR(us))
+		return PTR_ERR(us);
+
+	fsg_intf_desc.iInterface = us[FSG_STRING_INTERFACE].id;
 
 	/*
 	 * Some peripheral controllers are known not to be able to
 	 * halt bulk endpoints correctly.  If one of them is present,
 	 * disable stalls.
 	 */
-	common->can_stall = cfg->can_stall &&
-		!(gadget_is_at91(common->gadget));
+	common->can_stall = can_stall && !(gadget_is_at91(common->gadget));
 
-	spin_lock_init(&common->lock);
-	kref_init(&common->ref);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fsg_common_set_cdev);
 
-	/* Tell the thread to start working */
-	common->thread_task =
-		kthread_create(fsg_main_thread, common, "file-storage");
-	if (IS_ERR(common->thread_task)) {
-		rc = PTR_ERR(common->thread_task);
-		goto error_release;
+static inline int fsg_common_add_sysfs(struct fsg_common *common,
+				       struct fsg_lun *lun)
+{
+	int rc;
+
+	rc = device_register(&lun->dev);
+	if (rc) {
+		put_device(&lun->dev);
+		return rc;
 	}
-	init_completion(&common->thread_notifier);
-	init_waitqueue_head(&common->fsg_wait);
 
-	/* Information */
-	INFO(common, FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
-	INFO(common, "Number of LUNs=%d\n", common->nluns);
+	rc = device_create_file(&lun->dev,
+				lun->cdrom
+			      ? &dev_attr_ro_cdrom
+			      : &dev_attr_ro);
+	if (rc)
+		goto error;
+	rc = device_create_file(&lun->dev,
+				lun->removable
+			      ? &dev_attr_file
+			      : &dev_attr_file_nonremovable);
+	if (rc)
+		goto error;
+	rc = device_create_file(&lun->dev, &dev_attr_nofua);
+	if (rc)
+		goto error;
+
+	return 0;
+
+error:
+	/* removing nonexistent files is a no-op */
+	fsg_common_remove_sysfs(lun);
+	device_unregister(&lun->dev);
+	return rc;
+}
+
+int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg,
+			  unsigned int id, const char *name,
+			  const char **name_pfx)
+{
+	struct fsg_lun *lun;
+	char *pathbuf, *p;
+	int rc = -ENOMEM;
+
+	if (!common->nluns || !common->luns)
+		return -ENODEV;
+
+	if (common->luns[id])
+		return -EBUSY;
+
+	if (!cfg->filename && !cfg->removable) {
+		pr_err("no file given for LUN%d\n", id);
+		return -EINVAL;
+	}
+
+	lun = kzalloc(sizeof(*lun), GFP_KERNEL);
+	if (!lun)
+		return -ENOMEM;
+
+	lun->name_pfx = name_pfx;
+
+	lun->cdrom = !!cfg->cdrom;
+	lun->ro = cfg->cdrom || cfg->ro;
+	lun->initially_ro = lun->ro;
+	lun->removable = !!cfg->removable;
+
+	if (!common->sysfs) {
+		/* we DON'T own the name!*/
+		lun->name = name;
+	} else {
+		lun->dev.release = fsg_lun_release;
+		lun->dev.parent = &common->gadget->dev;
+		dev_set_drvdata(&lun->dev, &common->filesem);
+		dev_set_name(&lun->dev, "%s", name);
+		lun->name = dev_name(&lun->dev);
+
+		rc = fsg_common_add_sysfs(common, lun);
+		if (rc) {
+			pr_info("failed to register LUN%d: %d\n", id, rc);
+			goto error_sysfs;
+		}
+	}
+
+	common->luns[id] = lun;
+
+	if (cfg->filename) {
+		rc = fsg_lun_open(lun, cfg->filename);
+		if (rc)
+			goto error_lun;
+	}
 
 	pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
-	for (i = 0, nluns = common->nluns, curlun = common->luns;
-	     i < nluns;
-	     ++curlun, ++i) {
-		char *p = "(no medium)";
-		if (fsg_lun_is_open(curlun)) {
-			p = "(error)";
-			if (pathbuf) {
-				p = d_path(&curlun->filp->f_path,
-					   pathbuf, PATH_MAX);
-				if (IS_ERR(p))
-					p = "(error)";
-			}
+	p = "(no medium)";
+	if (fsg_lun_is_open(lun)) {
+		p = "(error)";
+		if (pathbuf) {
+			p = d_path(&lun->filp->f_path, pathbuf, PATH_MAX);
+			if (IS_ERR(p))
+				p = "(error)";
 		}
-		LINFO(curlun, "LUN: %s%s%sfile: %s\n",
-		      curlun->removable ? "removable " : "",
-		      curlun->ro ? "read only " : "",
-		      curlun->cdrom ? "CD-ROM " : "",
-		      p);
 	}
+	pr_info("LUN: %s%s%sfile: %s\n",
+	      lun->removable ? "removable " : "",
+	      lun->ro ? "read only " : "",
+	      lun->cdrom ? "CD-ROM " : "",
+	      p);
 	kfree(pathbuf);
 
+	return 0;
+
+error_lun:
+	if (common->sysfs) {
+		fsg_common_remove_sysfs(lun);
+		device_unregister(&lun->dev);
+	}
+	fsg_lun_close(lun);
+	common->luns[id] = NULL;
+error_sysfs:
+	kfree(lun);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(fsg_common_create_lun);
+
+int fsg_common_create_luns(struct fsg_common *common, struct fsg_config *cfg)
+{
+	char buf[8]; /* enough for 100000000 different numbers, decimal */
+	int i, rc;
+
+	for (i = 0; i < common->nluns; ++i) {
+		snprintf(buf, sizeof(buf), "lun%d", i);
+		rc = fsg_common_create_lun(common, &cfg->luns[i], i, buf, NULL);
+		if (rc)
+			goto fail;
+	}
+
+	pr_info("Number of LUNs=%d\n", common->nluns);
+
+	return 0;
+
+fail:
+	_fsg_common_remove_luns(common, i);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(fsg_common_create_luns);
+
+void fsg_common_set_inquiry_string(struct fsg_common *common, const char *vn,
+				   const char *pn)
+{
+	int i;
+
+	/* Prepare inquiryString */
+	i = get_default_bcdDevice();
+	snprintf(common->inquiry_string, sizeof(common->inquiry_string),
+		 "%-8s%-16s%04x", vn ?: "Linux",
+		 /* Assume product name dependent on the first LUN */
+		 pn ?: ((*common->luns)->cdrom
+		     ? "File-CD Gadget"
+		     : "File-Stor Gadget"),
+		 i);
+}
+EXPORT_SYMBOL_GPL(fsg_common_set_inquiry_string);
+
+int fsg_common_run_thread(struct fsg_common *common)
+{
+	common->state = FSG_STATE_IDLE;
+	/* Tell the thread to start working */
+	common->thread_task =
+		kthread_create(fsg_main_thread, common, "file-storage");
+	if (IS_ERR(common->thread_task)) {
+		common->state = FSG_STATE_TERMINATED;
+		return PTR_ERR(common->thread_task);
+	}
+
 	DBG(common, "I/O thread pid: %d\n", task_pid_nr(common->thread_task));
 
 	wake_up_process(common->thread_task);
 
-	return common;
-
-error_luns:
-	common->nluns = i + 1;
-error_release:
-	common->state = FSG_STATE_TERMINATED;	/* The thread is dead */
-	/* Call fsg_common_release() directly, ref might be not initialised. */
-	fsg_common_release(&common->ref);
-	return ERR_PTR(rc);
+	return 0;
 }
+EXPORT_SYMBOL_GPL(fsg_common_run_thread);
 
 static void fsg_common_release(struct kref *ref)
 {
@@ -2824,36 +3068,26 @@ static void fsg_common_release(struct kref *ref)
 	}
 
 	if (likely(common->luns)) {
-		struct fsg_lun *lun = common->luns;
+		struct fsg_lun **lun_it = common->luns;
 		unsigned i = common->nluns;
 
 		/* In error recovery common->nluns may be zero. */
-		for (; i; --i, ++lun) {
-			device_remove_file(&lun->dev, &dev_attr_nofua);
-			device_remove_file(&lun->dev,
-					   lun->cdrom
-					 ? &dev_attr_ro_cdrom
-					 : &dev_attr_ro);
-			device_remove_file(&lun->dev,
-					   lun->removable
-					 ? &dev_attr_file
-					 : &dev_attr_file_nonremovable);
+		for (; i; --i, ++lun_it) {
+			struct fsg_lun *lun = *lun_it;
+			if (!lun)
+				continue;
+			if (common->sysfs)
+				fsg_common_remove_sysfs(lun);
 			fsg_lun_close(lun);
-			device_unregister(&lun->dev);
+			if (common->sysfs)
+				device_unregister(&lun->dev);
+			kfree(lun);
 		}
 
 		kfree(common->luns);
 	}
 
-	{
-		struct fsg_buffhd *bh = common->buffhds;
-		unsigned i = fsg_num_buffers;
-		do {
-			kfree(bh->buf);
-		} while (++bh, --i);
-	}
-
-	kfree(common->buffhds);
+	_fsg_common_free_buffers(common->buffhds, common->fsg_num_buffers);
 	if (common->free_storage_on_release)
 		kfree(common);
 }
@@ -2861,24 +3095,6 @@ static void fsg_common_release(struct kref *ref)
 
 /*-------------------------------------------------------------------------*/
 
-static void fsg_unbind(struct usb_configuration *c, struct usb_function *f)
-{
-	struct fsg_dev		*fsg = fsg_from_func(f);
-	struct fsg_common	*common = fsg->common;
-
-	DBG(fsg, "unbind\n");
-	if (fsg->common->fsg == fsg) {
-		fsg->common->new_fsg = NULL;
-		raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
-		/* FIXME: make interruptible or killable somehow? */
-		wait_event(common->fsg_wait, common->fsg != fsg);
-	}
-
-	fsg_common_put(common);
-	usb_free_all_descriptors(&fsg->function);
-	kfree(fsg);
-}
-
 static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct fsg_dev		*fsg = fsg_from_func(f);
@@ -2887,6 +3103,19 @@ static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
 	struct usb_ep		*ep;
 	unsigned		max_burst;
 	int			ret;
+	struct fsg_opts		*opts;
+
+	opts = fsg_opts_from_func_inst(f->fi);
+	if (!opts->no_configfs) {
+		ret = fsg_common_set_cdev(fsg->common, c->cdev,
+					  fsg->common->can_stall);
+		if (ret)
+			return ret;
+		fsg_common_set_inquiry_string(fsg->common, 0, 0);
+		ret = fsg_common_run_thread(fsg->common);
+		if (ret)
+			return ret;
+	}
 
 	fsg->gadget = gadget;
 
@@ -2939,95 +3168,472 @@ autoconf_fail:
 	return -ENOTSUPP;
 }
 
-/****************************** ADD FUNCTION ******************************/
+/****************************** ALLOCATE FUNCTION *************************/
 
-static struct usb_gadget_strings *fsg_strings_array[] = {
-	&fsg_stringtab,
+static void fsg_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct fsg_dev		*fsg = fsg_from_func(f);
+	struct fsg_common	*common = fsg->common;
+
+	DBG(fsg, "unbind\n");
+	if (fsg->common->fsg == fsg) {
+		fsg->common->new_fsg = NULL;
+		raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
+		/* FIXME: make interruptible or killable somehow? */
+		wait_event(common->fsg_wait, common->fsg != fsg);
+	}
+
+	usb_free_all_descriptors(&fsg->function);
+}
+
+static inline struct fsg_lun_opts *to_fsg_lun_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct fsg_lun_opts, group);
+}
+
+static inline struct fsg_opts *to_fsg_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct fsg_opts,
+			    func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(fsg_lun_opts);
+CONFIGFS_ATTR_OPS(fsg_lun_opts);
+
+static void fsg_lun_attr_release(struct config_item *item)
+{
+	struct fsg_lun_opts *lun_opts;
+
+	lun_opts = to_fsg_lun_opts(item);
+	kfree(lun_opts);
+}
+
+static struct configfs_item_operations fsg_lun_item_ops = {
+	.release		= fsg_lun_attr_release,
+	.show_attribute		= fsg_lun_opts_attr_show,
+	.store_attribute	= fsg_lun_opts_attr_store,
+};
+
+static ssize_t fsg_lun_opts_file_show(struct fsg_lun_opts *opts, char *page)
+{
+	struct fsg_opts *fsg_opts;
+
+	fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
+
+	return fsg_show_file(opts->lun, &fsg_opts->common->filesem, page);
+}
+
+static ssize_t fsg_lun_opts_file_store(struct fsg_lun_opts *opts,
+				       const char *page, size_t len)
+{
+	struct fsg_opts *fsg_opts;
+
+	fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
+
+	return fsg_store_file(opts->lun, &fsg_opts->common->filesem, page, len);
+}
+
+static struct fsg_lun_opts_attribute fsg_lun_opts_file =
+	__CONFIGFS_ATTR(file, S_IRUGO | S_IWUSR, fsg_lun_opts_file_show,
+			fsg_lun_opts_file_store);
+
+static ssize_t fsg_lun_opts_ro_show(struct fsg_lun_opts *opts, char *page)
+{
+	return fsg_show_ro(opts->lun, page);
+}
+
+static ssize_t fsg_lun_opts_ro_store(struct fsg_lun_opts *opts,
+				       const char *page, size_t len)
+{
+	struct fsg_opts *fsg_opts;
+
+	fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
+
+	return fsg_store_ro(opts->lun, &fsg_opts->common->filesem, page, len);
+}
+
+static struct fsg_lun_opts_attribute fsg_lun_opts_ro =
+	__CONFIGFS_ATTR(ro, S_IRUGO | S_IWUSR, fsg_lun_opts_ro_show,
+			fsg_lun_opts_ro_store);
+
+static ssize_t fsg_lun_opts_removable_show(struct fsg_lun_opts *opts,
+					   char *page)
+{
+	return fsg_show_removable(opts->lun, page);
+}
+
+static ssize_t fsg_lun_opts_removable_store(struct fsg_lun_opts *opts,
+				       const char *page, size_t len)
+{
+	return fsg_store_removable(opts->lun, page, len);
+}
+
+static struct fsg_lun_opts_attribute fsg_lun_opts_removable =
+	__CONFIGFS_ATTR(removable, S_IRUGO | S_IWUSR,
+			fsg_lun_opts_removable_show,
+			fsg_lun_opts_removable_store);
+
+static ssize_t fsg_lun_opts_cdrom_show(struct fsg_lun_opts *opts, char *page)
+{
+	return fsg_show_cdrom(opts->lun, page);
+}
+
+static ssize_t fsg_lun_opts_cdrom_store(struct fsg_lun_opts *opts,
+				       const char *page, size_t len)
+{
+	struct fsg_opts *fsg_opts;
+
+	fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
+
+	return fsg_store_cdrom(opts->lun, &fsg_opts->common->filesem, page,
+			       len);
+}
+
+static struct fsg_lun_opts_attribute fsg_lun_opts_cdrom =
+	__CONFIGFS_ATTR(cdrom, S_IRUGO | S_IWUSR, fsg_lun_opts_cdrom_show,
+			fsg_lun_opts_cdrom_store);
+
+static ssize_t fsg_lun_opts_nofua_show(struct fsg_lun_opts *opts, char *page)
+{
+	return fsg_show_nofua(opts->lun, page);
+}
+
+static ssize_t fsg_lun_opts_nofua_store(struct fsg_lun_opts *opts,
+				       const char *page, size_t len)
+{
+	return fsg_store_nofua(opts->lun, page, len);
+}
+
+static struct fsg_lun_opts_attribute fsg_lun_opts_nofua =
+	__CONFIGFS_ATTR(nofua, S_IRUGO | S_IWUSR, fsg_lun_opts_nofua_show,
+			fsg_lun_opts_nofua_store);
+
+static struct configfs_attribute *fsg_lun_attrs[] = {
+	&fsg_lun_opts_file.attr,
+	&fsg_lun_opts_ro.attr,
+	&fsg_lun_opts_removable.attr,
+	&fsg_lun_opts_cdrom.attr,
+	&fsg_lun_opts_nofua.attr,
 	NULL,
 };
 
-static int fsg_bind_config(struct usb_composite_dev *cdev,
-			   struct usb_configuration *c,
-			   struct fsg_common *common)
+static struct config_item_type fsg_lun_type = {
+	.ct_item_ops	= &fsg_lun_item_ops,
+	.ct_attrs	= fsg_lun_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *fsg_lun_make(struct config_group *group,
+					 const char *name)
 {
-	struct fsg_dev *fsg;
+	struct fsg_lun_opts *opts;
+	struct fsg_opts *fsg_opts;
+	struct fsg_lun_config config;
+	char *num_str;
+	u8 num;
+	int ret;
+
+	num_str = strchr(name, '.');
+	if (!num_str) {
+		pr_err("Unable to locate . in LUN.NUMBER\n");
+		return ERR_PTR(-EINVAL);
+	}
+	num_str++;
+
+	ret = kstrtou8(num_str, 0, &num);
+	if (ret)
+		return ERR_PTR(ret);
+
+	fsg_opts = to_fsg_opts(&group->cg_item);
+	if (num >= FSG_MAX_LUNS)
+		return ERR_PTR(-ERANGE);
+
+	mutex_lock(&fsg_opts->lock);
+	if (fsg_opts->refcnt || fsg_opts->common->luns[num]) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	memset(&config, 0, sizeof(config));
+	config.removable = true;
+
+	ret = fsg_common_create_lun(fsg_opts->common, &config, num, name,
+				    (const char **)&group->cg_item.ci_name);
+	if (ret) {
+		kfree(opts);
+		goto out;
+	}
+	opts->lun = fsg_opts->common->luns[num];
+	opts->lun_id = num;
+	mutex_unlock(&fsg_opts->lock);
+
+	config_group_init_type_name(&opts->group, name, &fsg_lun_type);
+
+	return &opts->group;
+out:
+	mutex_unlock(&fsg_opts->lock);
+	return ERR_PTR(ret);
+}
+
+static void fsg_lun_drop(struct config_group *group, struct config_item *item)
+{
+	struct fsg_lun_opts *lun_opts;
+	struct fsg_opts *fsg_opts;
+
+	lun_opts = to_fsg_lun_opts(item);
+	fsg_opts = to_fsg_opts(&group->cg_item);
+
+	mutex_lock(&fsg_opts->lock);
+	if (fsg_opts->refcnt) {
+		struct config_item *gadget;
+
+		gadget = group->cg_item.ci_parent->ci_parent;
+		unregister_gadget_item(gadget);
+	}
+
+	fsg_common_remove_lun(lun_opts->lun, fsg_opts->common->sysfs);
+	fsg_opts->common->luns[lun_opts->lun_id] = NULL;
+	lun_opts->lun_id = 0;
+	mutex_unlock(&fsg_opts->lock);
+
+	config_item_put(item);
+}
+
+CONFIGFS_ATTR_STRUCT(fsg_opts);
+CONFIGFS_ATTR_OPS(fsg_opts);
+
+static void fsg_attr_release(struct config_item *item)
+{
+	struct fsg_opts *opts = to_fsg_opts(item);
+
+	usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations fsg_item_ops = {
+	.release		= fsg_attr_release,
+	.show_attribute		= fsg_opts_attr_show,
+	.store_attribute	= fsg_opts_attr_store,
+};
+
+static ssize_t fsg_opts_stall_show(struct fsg_opts *opts, char *page)
+{
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d", opts->common->can_stall);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t fsg_opts_stall_store(struct fsg_opts *opts, const char *page,
+				    size_t len)
+{
+	int ret;
+	bool stall;
+
+	mutex_lock(&opts->lock);
+
+	if (opts->refcnt) {
+		mutex_unlock(&opts->lock);
+		return -EBUSY;
+	}
+
+	ret = strtobool(page, &stall);
+	if (!ret) {
+		opts->common->can_stall = stall;
+		ret = len;
+	}
+
+	mutex_unlock(&opts->lock);
+
+	return ret;
+}
+
+static struct fsg_opts_attribute fsg_opts_stall =
+	__CONFIGFS_ATTR(stall, S_IRUGO | S_IWUSR, fsg_opts_stall_show,
+			fsg_opts_stall_store);
+
+#ifdef CONFIG_USB_GADGET_DEBUG_FILES
+static ssize_t fsg_opts_num_buffers_show(struct fsg_opts *opts, char *page)
+{
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d", opts->common->fsg_num_buffers);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t fsg_opts_num_buffers_store(struct fsg_opts *opts,
+					  const char *page, size_t len)
+{
+	int ret;
+	u8 num;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		goto end;
+
+	ret = fsg_num_buffers_validate(num);
+	if (ret)
+		goto end;
+
+	fsg_common_set_num_buffers(opts->common, num);
+	ret = len;
+
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+static struct fsg_opts_attribute fsg_opts_num_buffers =
+	__CONFIGFS_ATTR(num_buffers, S_IRUGO | S_IWUSR,
+			fsg_opts_num_buffers_show,
+			fsg_opts_num_buffers_store);
+
+#endif
+
+static struct configfs_attribute *fsg_attrs[] = {
+	&fsg_opts_stall.attr,
+#ifdef CONFIG_USB_GADGET_DEBUG_FILES
+	&fsg_opts_num_buffers.attr,
+#endif
+	NULL,
+};
+
+static struct configfs_group_operations fsg_group_ops = {
+	.make_group	= fsg_lun_make,
+	.drop_item	= fsg_lun_drop,
+};
+
+static struct config_item_type fsg_func_type = {
+	.ct_item_ops	= &fsg_item_ops,
+	.ct_group_ops	= &fsg_group_ops,
+	.ct_attrs	= fsg_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static void fsg_free_inst(struct usb_function_instance *fi)
+{
+	struct fsg_opts *opts;
+
+	opts = fsg_opts_from_func_inst(fi);
+	fsg_common_put(opts->common);
+	kfree(opts);
+}
+
+static struct usb_function_instance *fsg_alloc_inst(void)
+{
+	struct fsg_opts *opts;
+	struct fsg_lun_config config;
 	int rc;
 
-	fsg = kzalloc(sizeof *fsg, GFP_KERNEL);
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+	mutex_init(&opts->lock);
+	opts->func_inst.free_func_inst = fsg_free_inst;
+	opts->common = fsg_common_setup(opts->common);
+	if (IS_ERR(opts->common)) {
+		rc = PTR_ERR(opts->common);
+		goto release_opts;
+	}
+	rc = fsg_common_set_nluns(opts->common, FSG_MAX_LUNS);
+	if (rc)
+		goto release_opts;
+
+	rc = fsg_common_set_num_buffers(opts->common,
+					CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS);
+	if (rc)
+		goto release_luns;
+
+	pr_info(FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
+
+	memset(&config, 0, sizeof(config));
+	config.removable = true;
+	rc = fsg_common_create_lun(opts->common, &config, 0, "lun.0",
+			(const char **)&opts->func_inst.group.cg_item.ci_name);
+	opts->lun0.lun = opts->common->luns[0];
+	opts->lun0.lun_id = 0;
+	config_group_init_type_name(&opts->lun0.group, "lun.0", &fsg_lun_type);
+	opts->default_groups[0] = &opts->lun0.group;
+	opts->func_inst.group.default_groups = opts->default_groups;
+
+	config_group_init_type_name(&opts->func_inst.group, "", &fsg_func_type);
+
+	return &opts->func_inst;
+
+release_luns:
+	kfree(opts->common->luns);
+release_opts:
+	kfree(opts);
+	return ERR_PTR(rc);
+}
+
+static void fsg_free(struct usb_function *f)
+{
+	struct fsg_dev *fsg;
+	struct fsg_opts *opts;
+
+	fsg = container_of(f, struct fsg_dev, function);
+	opts = container_of(f->fi, struct fsg_opts, func_inst);
+
+	mutex_lock(&opts->lock);
+	opts->refcnt--;
+	mutex_unlock(&opts->lock);
+
+	kfree(fsg);
+}
+
+static struct usb_function *fsg_alloc(struct usb_function_instance *fi)
+{
+	struct fsg_opts *opts = fsg_opts_from_func_inst(fi);
+	struct fsg_common *common = opts->common;
+	struct fsg_dev *fsg;
+
+	fsg = kzalloc(sizeof(*fsg), GFP_KERNEL);
 	if (unlikely(!fsg))
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
-	fsg->function.name        = FSG_DRIVER_DESC;
-	fsg->function.strings     = fsg_strings_array;
-	fsg->function.bind        = fsg_bind;
-	fsg->function.unbind      = fsg_unbind;
-	fsg->function.setup       = fsg_setup;
-	fsg->function.set_alt     = fsg_set_alt;
-	fsg->function.disable     = fsg_disable;
+	mutex_lock(&opts->lock);
+	opts->refcnt++;
+	mutex_unlock(&opts->lock);
+	fsg->function.name	= FSG_DRIVER_DESC;
+	fsg->function.bind	= fsg_bind;
+	fsg->function.unbind	= fsg_unbind;
+	fsg->function.setup	= fsg_setup;
+	fsg->function.set_alt	= fsg_set_alt;
+	fsg->function.disable	= fsg_disable;
+	fsg->function.free_func	= fsg_free;
 
 	fsg->common               = common;
-	/*
-	 * Our caller holds a reference to common structure so we
-	 * don't have to be worry about it being freed until we return
-	 * from this function.  So instead of incrementing counter now
-	 * and decrement in error recovery we increment it only when
-	 * call to usb_add_function() was successful.
-	 */
 
-	rc = usb_add_function(c, &fsg->function);
-	if (unlikely(rc))
-		kfree(fsg);
-	else
-		fsg_common_get(fsg->common);
-	return rc;
+	return &fsg->function;
 }
 
+DECLARE_USB_FUNCTION_INIT(mass_storage, fsg_alloc_inst, fsg_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michal Nazarewicz");
 
 /************************* Module parameters *************************/
 
-struct fsg_module_parameters {
-	char		*file[FSG_MAX_LUNS];
-	bool		ro[FSG_MAX_LUNS];
-	bool		removable[FSG_MAX_LUNS];
-	bool		cdrom[FSG_MAX_LUNS];
-	bool		nofua[FSG_MAX_LUNS];
-
-	unsigned int	file_count, ro_count, removable_count, cdrom_count;
-	unsigned int	nofua_count;
-	unsigned int	luns;	/* nluns */
-	bool		stall;	/* can_stall */
-};
 
-#define _FSG_MODULE_PARAM_ARRAY(prefix, params, name, type, desc)	\
-	module_param_array_named(prefix ## name, params.name, type,	\
-				 &prefix ## params.name ## _count,	\
-				 S_IRUGO);				\
-	MODULE_PARM_DESC(prefix ## name, desc)
-
-#define _FSG_MODULE_PARAM(prefix, params, name, type, desc)		\
-	module_param_named(prefix ## name, params.name, type,		\
-			   S_IRUGO);					\
-	MODULE_PARM_DESC(prefix ## name, desc)
-
-#define FSG_MODULE_PARAMETERS(prefix, params)				\
-	_FSG_MODULE_PARAM_ARRAY(prefix, params, file, charp,		\
-				"names of backing files or devices");	\
-	_FSG_MODULE_PARAM_ARRAY(prefix, params, ro, bool,		\
-				"true to force read-only");		\
-	_FSG_MODULE_PARAM_ARRAY(prefix, params, removable, bool,	\
-				"true to simulate removable media");	\
-	_FSG_MODULE_PARAM_ARRAY(prefix, params, cdrom, bool,		\
-				"true to simulate CD-ROM instead of disk"); \
-	_FSG_MODULE_PARAM_ARRAY(prefix, params, nofua, bool,		\
-				"true to ignore SCSI WRITE(10,12) FUA bit"); \
-	_FSG_MODULE_PARAM(prefix, params, luns, uint,			\
-			  "number of LUNs");				\
-	_FSG_MODULE_PARAM(prefix, params, stall, bool,			\
-			  "false to prevent bulk stalls")
-
-static void
-fsg_config_from_params(struct fsg_config *cfg,
-		       const struct fsg_module_parameters *params)
+void fsg_config_from_params(struct fsg_config *cfg,
+		       const struct fsg_module_parameters *params,
+		       unsigned int fsg_num_buffers)
 {
 	struct fsg_lun_config *lun;
 	unsigned i;
@@ -3055,19 +3661,7 @@ fsg_config_from_params(struct fsg_config *cfg,
 
 	/* Finalise */
 	cfg->can_stall = params->stall;
+	cfg->fsg_num_buffers = fsg_num_buffers;
 }
+EXPORT_SYMBOL_GPL(fsg_config_from_params);
 
-static inline struct fsg_common *
-fsg_common_from_params(struct fsg_common *common,
-		       struct usb_composite_dev *cdev,
-		       const struct fsg_module_parameters *params)
-	__attribute__((unused));
-static inline struct fsg_common *
-fsg_common_from_params(struct fsg_common *common,
-		       struct usb_composite_dev *cdev,
-		       const struct fsg_module_parameters *params)
-{
-	struct fsg_config cfg;
-	fsg_config_from_params(&cfg, params);
-	return fsg_common_init(common, cdev, &cfg);
-}