usb/gadget: f_mass_storage: convert to new function interface with backward compatibility

Converting mass storage to the new function interface requires converting
the USB mass storage's function code and its users.
This patch converts the f_mass_storage.c to the new function interface.
The file is now compiled into a separate usb_f_mass_storage.ko module.
The old function interface is provided by means of a preprocessor conditional
directives. After all users are converted, the old interface can be removed.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

7 files changed, 212 insertions, 20 deletions

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index b5e6c2e1097..fc8012ae166 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -540,6 +540,9 @@ config USB_F_RNDIS
 config USB_U_MS
 	tristate
 
+config USB_F_MASS_STORAGE
+	tristate
+
 choice
 	tristate "USB Gadget Drivers"
 	default USB_ETH
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 3bb34ef2aed..d232706118d 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -62,6 +62,8 @@ usb_f_rndis-y			:= f_rndis.o
 obj-$(CONFIG_USB_F_RNDIS)	+= usb_f_rndis.o
 u_ms-y				:= storage_common.o
 obj-$(CONFIG_USB_U_MS)		+= u_ms.o
+usb_f_mass_storage-y		:= f_mass_storage.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 992ffb00272..31aae8fce42 100644
--- a/drivers/usb/gadget/acm_ms.c
+++ b/drivers/usb/gadget/acm_ms.c
@@ -40,6 +40,7 @@
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
+#define USB_FMS_INCLUDED
 #include "f_mass_storage.c"
 
 /*-------------------------------------------------------------------------*/
diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index 7ef99f1c134..0a2b3ae5621 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -213,6 +213,7 @@
 #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>
@@ -2592,11 +2593,17 @@ void fsg_common_get(struct fsg_common *common)
 {
 	kref_get(&common->ref);
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_get);
+#endif
 
 void fsg_common_put(struct fsg_common *common)
 {
 	kref_put(&common->ref, fsg_common_release);
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_put);
+#endif
 
 /* check if fsg_num_buffers is within a valid range */
 static inline int fsg_num_buffers_validate(unsigned int fsg_num_buffers)
@@ -2634,6 +2641,9 @@ void fsg_common_set_sysfs(struct fsg_common *common, bool sysfs)
 {
 	common->sysfs = sysfs;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_set_sysfs);
+#endif
 
 static void _fsg_common_free_buffers(struct fsg_buffhd *buffhds, unsigned n)
 {
@@ -2685,12 +2695,18 @@ error_release:
 
 	return -ENOMEM;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_set_num_buffers);
+#endif
 
 void fsg_common_free_buffers(struct fsg_common *common)
 {
 	_fsg_common_free_buffers(common->buffhds, common->fsg_num_buffers);
 	common->buffhds = NULL;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_free_buffers);
+#endif
 
 int fsg_common_set_nluns(struct fsg_common *common, int nluns)
 {
@@ -2716,6 +2732,9 @@ int fsg_common_set_nluns(struct fsg_common *common, int nluns)
 
 	return 0;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_set_nluns);
+#endif
 
 void fsg_common_free_luns(struct fsg_common *common)
 {
@@ -2723,17 +2742,26 @@ void fsg_common_free_luns(struct fsg_common *common)
 	kfree(common->luns);
 	common->luns = NULL;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_free_luns);
+#endif
 
 void fsg_common_set_ops(struct fsg_common *common,
 			const struct fsg_operations *ops)
 {
 	common->ops = ops;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_set_ops);
+#endif
 
 void fsg_common_set_private_data(struct fsg_common *common, void *priv)
 {
 	common->private_data = priv;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_set_private_data);
+#endif
 
 int fsg_common_set_cdev(struct fsg_common *common,
 			 struct usb_composite_dev *cdev, bool can_stall)
@@ -2763,6 +2791,9 @@ int fsg_common_set_cdev(struct fsg_common *common,
 
 	return 0;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_set_cdev);
+#endif
 
 static inline int fsg_common_add_sysfs(struct fsg_common *common,
 				       struct fsg_lun *lun)
@@ -2827,6 +2858,9 @@ void fsg_common_remove_lun(struct fsg_lun *lun, bool sysfs)
 	kfree(lun->name);
 	kfree(lun);
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_remove_lun);
+#endif
 
 void _fsg_common_remove_luns(struct fsg_common *common, int n)
 {
@@ -2843,6 +2877,9 @@ void fsg_common_remove_luns(struct fsg_common *common)
 {
 	_fsg_common_remove_luns(common, common->nluns);
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_remove_luns);
+#endif
 
 #define MAX_LUN_NAME_LEN 80
 
@@ -2939,6 +2976,9 @@ error_name:
 	kfree(lun);
 	return rc;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_create_lun);
+#endif
 
 int fsg_common_create_luns(struct fsg_common *common, struct fsg_config *cfg)
 {
@@ -2960,6 +3000,9 @@ fail:
 	_fsg_common_remove_luns(common, i);
 	return rc;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_create_luns);
+#endif
 
 void fsg_common_set_inquiry_string(struct fsg_common *common, const char *vn,
 				   const char *pn)
@@ -2976,6 +3019,9 @@ void fsg_common_set_inquiry_string(struct fsg_common *common, const char *vn,
 		     : "File-Stor Gadget"),
 		 i);
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_set_inquiry_string);
+#endif
 
 int fsg_common_run_thread(struct fsg_common *common)
 {
@@ -2994,6 +3040,9 @@ int fsg_common_run_thread(struct fsg_common *common)
 
 	return 0;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_run_thread);
+#endif
 
 struct fsg_common *fsg_common_init(struct fsg_common *common,
 				   struct usb_composite_dev *cdev,
@@ -3048,6 +3097,9 @@ error_release:
 	fsg_common_release(&common->ref);
 	return ERR_PTR(rc);
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_common_init);
+#endif
 
 static void fsg_common_release(struct kref *ref)
 {
@@ -3090,24 +3142,6 @@ 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);
@@ -3117,6 +3151,21 @@ static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
 	unsigned		max_burst;
 	int			ret;
 
+#ifndef USB_FMS_INCLUDED
+	struct fsg_opts		*opts;
+	opts = container_of(f->fi, struct fsg_opts, func_inst);
+	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;
+	}
+#endif
+
 	fsg->gadget = gadget;
 
 	/* New interface */
@@ -3168,7 +3217,27 @@ autoconf_fail:
 	return -ENOTSUPP;
 }
 
-/****************************** ADD FUNCTION ******************************/
+/****************************** ALLOCATE FUNCTION *************************/
+
+#ifdef USB_FMS_INCLUDED
+
+static void old_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_config(struct usb_composite_dev *cdev,
 			   struct usb_configuration *c,
@@ -3183,7 +3252,7 @@ static int fsg_bind_config(struct usb_composite_dev *cdev,
 
 	fsg->function.name        = FSG_DRIVER_DESC;
 	fsg->function.bind        = fsg_bind;
-	fsg->function.unbind      = fsg_unbind;
+	fsg->function.unbind      = old_fsg_unbind;
 	fsg->function.setup       = fsg_setup;
 	fsg->function.set_alt     = fsg_set_alt;
 	fsg->function.disable     = fsg_disable;
@@ -3205,6 +3274,111 @@ static int fsg_bind_config(struct usb_composite_dev *cdev,
 	return rc;
 }
 
+#else
+
+static void fsg_free_inst(struct usb_function_instance *fi)
+{
+	struct fsg_opts *opts;
+
+	opts = container_of(fi, struct fsg_opts, func_inst);
+	fsg_common_put(opts->common);
+	kfree(opts);
+}
+
+static struct usb_function_instance *fsg_alloc_inst(void)
+{
+	struct fsg_opts *opts;
+	int ret;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+	opts->func_inst.free_func_inst = fsg_free_inst;
+	opts->common = fsg_common_setup(opts->common, false);
+	if (IS_ERR(opts->common)) {
+		ret = PTR_ERR(opts->common);
+		goto release_opts;
+	}
+	ret = fsg_common_set_nluns(opts->common, FSG_MAX_LUNS);
+	if (ret)
+		goto release_opts;
+
+	ret = fsg_common_set_num_buffers(opts->common,
+					 CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS);
+	if (ret)
+		goto release_luns;
+
+	pr_info(FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
+
+	return &opts->func_inst;
+
+release_luns:
+	kfree(opts->common->luns);
+release_opts:
+	kfree(opts);
+	return ERR_PTR(ret);
+}
+
+static void fsg_free(struct usb_function *f)
+{
+	struct fsg_dev *fsg;
+
+	fsg = container_of(f, struct fsg_dev, function);
+
+	kfree(fsg);
+}
+
+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 struct usb_function *fsg_alloc(struct usb_function_instance *fi)
+{
+	struct fsg_opts *opts = container_of(fi, struct fsg_opts, func_inst);
+	struct fsg_common *common = opts->common;
+	struct fsg_dev *fsg;
+
+	fsg = kzalloc(sizeof(*fsg), GFP_KERNEL);
+	if (unlikely(!fsg))
+		return ERR_PTR(-ENOMEM);
+
+	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.
+	 */
+
+	return &fsg->function;
+}
+
+DECLARE_USB_FUNCTION_INIT(mass_storage, fsg_alloc_inst, fsg_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michal Nazarewicz");
+
+#endif
 
 /************************* Module parameters *************************/
 
@@ -3241,4 +3415,7 @@ void fsg_config_from_params(struct fsg_config *cfg,
 	cfg->can_stall = params->stall;
 	cfg->fsg_num_buffers = fsg_num_buffers;
 }
+#ifndef USB_FMS_INCLUDED
+EXPORT_SYMBOL(fsg_config_from_params);
+#endif
 
diff --git a/drivers/usb/gadget/f_mass_storage.h b/drivers/usb/gadget/f_mass_storage.h
index 4445e823c5e..7aed1d903a8 100644
--- a/drivers/usb/gadget/f_mass_storage.h
+++ b/drivers/usb/gadget/f_mass_storage.h
@@ -1,6 +1,7 @@
 #ifndef USB_F_MASS_STORAGE_H
 #define USB_F_MASS_STORAGE_H
 
+#include <linux/usb/composite.h>
 #include "storage_common.h"
 
 struct fsg_module_parameters {
@@ -70,6 +71,12 @@ struct fsg_operations {
 	int (*thread_exits)(struct fsg_common *common);
 };
 
+struct fsg_opts {
+	struct fsg_common *common;
+	struct usb_function_instance func_inst;
+	bool no_configfs; /* for legacy gadgets */
+};
+
 struct fsg_lun_config {
 	const char *filename;
 	char ro;
diff --git a/drivers/usb/gadget/mass_storage.c b/drivers/usb/gadget/mass_storage.c
index bf60a9a237e..6b798141b59 100644
--- a/drivers/usb/gadget/mass_storage.c
+++ b/drivers/usb/gadget/mass_storage.c
@@ -55,6 +55,7 @@
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
+#define USB_FMS_INCLUDED
 #include "f_mass_storage.c"
 
 /*-------------------------------------------------------------------------*/
diff --git a/drivers/usb/gadget/multi.c b/drivers/usb/gadget/multi.c
index f610d0154f8..c232f765ea6 100644
--- a/drivers/usb/gadget/multi.c
+++ b/drivers/usb/gadget/multi.c
@@ -41,6 +41,7 @@ MODULE_LICENSE("GPL");
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
+#define USB_FMS_INCLUDED
 #include "f_mass_storage.c"
 
 #define USBF_ECM_INCLUDED