Apply b894f60a23

brick/kernel/f_mass_storage.c

@@ -317,8 +317,8 @@ struct fsg_dev;
 /* Data shared by all the FSG instances. */
 struct fsg_common {
 	struct usb_gadget	*gadget;
-	struct fsg_dev		*fsg;
-	struct fsg_dev		*prev_fsg;
+	struct fsg_dev		*fsg, *new_fsg;
+	wait_queue_head_t	fsg_wait;
 
 	/* filesem protects: backing files in use */
 	struct rw_semaphore	filesem;
@@ -347,7 +347,6 @@ struct fsg_common {
 	enum fsg_state		state;		/* For exception handling */
 	unsigned int		exception_req_tag;
 
-	u8			config, new_config;
 	enum data_direction	data_dir;
 	u32			data_size;
 	u32			data_size_from_cmnd;
@@ -587,7 +586,7 @@ static int fsg_setup(struct usb_function *f,
 	u16			w_value = le16_to_cpu(ctrl->wValue);
 	u16			w_length = le16_to_cpu(ctrl->wLength);
 
-	if (!fsg->common->config)
+	if (!fsg_is_set(fsg->common))
 		return -EOPNOTSUPP;
 
 	switch (ctrl->bRequest) {
@@ -2267,24 +2266,20 @@ static int alloc_request(struct fsg_common *common, struct usb_ep *ep,
 	return -ENOMEM;
 }
 
-/*
- * Reset interface setting and re-init endpoint state (toggle etc).
- * Call with altsetting < 0 to disable the interface.  The only other
- * available altsetting is 0, which enables the interface.
- */
-static int do_set_interface(struct fsg_common *common, int altsetting)
+/* Reset interface setting and re-init endpoint state (toggle etc). */
+static int do_set_interface(struct fsg_common *common, struct fsg_dev *new_fsg)
 {
-	int	rc = 0;
-	int	i;
 	const struct usb_endpoint_descriptor *d;
+	struct fsg_dev *fsg;
+	int i, rc = 0;
 
 	if (common->running)
 		DBG(common, "reset interface\n");
 
 reset:
 	/* Deallocate the requests */
-	if (common->prev_fsg) {
-		struct fsg_dev *fsg = common->prev_fsg;
+	if (common->fsg) {
+		fsg = common->fsg;
 
 		for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
 			struct fsg_buffhd *bh = &common->buffhds[i];
@@ -2309,18 +2304,16 @@ reset:
 			fsg->bulk_out_enabled = 0;
 		}
 
-		common->prev_fsg = 0;
+		common->fsg = NULL;
+		wake_up(&common->fsg_wait);
 	}
 
 	common->running = 0;
-	if (altsetting < 0 || rc != 0)
+	if (!new_fsg || rc)
 		return rc;
 
-	DBG(common, "set interface %d\n", altsetting);
-
-	if (fsg_is_set(common)) {
-		struct fsg_dev *fsg = common->fsg;
-		common->prev_fsg = common->fsg;
+	common->fsg = new_fsg;
+	fsg = common->fsg;
 
 	/* Enable the endpoints */
 	d = fsg_ep_desc(common->gadget,
@@ -2359,39 +2352,6 @@ reset:
 	for (i = 0; i < common->nluns; ++i)
 		common->luns[i].unit_attention_data = SS_RESET_OCCURRED;
 	return rc;
-	} else {
-		return -EIO;
-	}
-}
-
-
-/*
- * Change our operational configuration.  This code must agree with the code
- * that returns config descriptors, and with interface altsetting code.
- *
- * It's also responsible for power management interactions.  Some
- * configurations might not work with our current power sources.
- * For now we just assume the gadget is always self-powered.
- */
-static int do_set_config(struct fsg_common *common, u8 new_config)
-{
-	int	rc = 0;
-
-	/* Disable the single interface */
-	if (common->config != 0) {
-		DBG(common, "reset config\n");
-		common->config = 0;
-		rc = do_set_interface(common, -1);
-	}
-
-	/* Enable the interface */
-	if (new_config != 0) {
-		common->config = new_config;
-		rc = do_set_interface(common, 0);
-		if (rc != 0)
-			common->config = 0;	/* Reset on errors */
-	}
-	return rc;
 }
 
 
@@ -2401,9 +2361,7 @@ static int do_set_config(struct fsg_common *common, u8 new_config)
 static int fsg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 {
 	struct fsg_dev *fsg = fsg_from_func(f);
-	fsg->common->prev_fsg = fsg->common->fsg;
-	fsg->common->fsg = fsg;
-	fsg->common->new_config = 1;
+	fsg->common->new_fsg = fsg;
 	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
 	return 0;
 }
@@ -2411,9 +2369,7 @@ static int fsg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 static void fsg_disable(struct usb_function *f)
 {
 	struct fsg_dev *fsg = fsg_from_func(f);
-	fsg->common->prev_fsg = fsg->common->fsg;
-	fsg->common->fsg = fsg;
-	fsg->common->new_config = 0;
+	fsg->common->new_fsg = NULL;
 	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
 }
 
@@ -2423,19 +2379,17 @@ static void fsg_disable(struct usb_function *f)
 static void handle_exception(struct fsg_common *common)
 {
 	siginfo_t		info;
-	int			sig;
 	int			i;
 	struct fsg_buffhd	*bh;
 	enum fsg_state		old_state;
-	u8			new_config;
 	struct fsg_lun		*curlun;
 	unsigned int		exception_req_tag;
-	int			rc;
 
 	/* Clear the existing signals.  Anything but SIGUSR1 is converted
 	 * into a high-priority EXIT exception. */
 	for (;;) {
-		sig = dequeue_signal_lock(current, &current->blocked, &info);
+		int sig =
+			dequeue_signal_lock(current, &current->blocked, &info);
 		if (!sig)
 			break;
 		if (sig != SIGUSR1) {
@@ -2446,7 +2400,7 @@ static void handle_exception(struct fsg_common *common)
 	}
 
 	/* Cancel all the pending transfers */
-	if (fsg_is_set(common)) {
+	if (likely(common->fsg)) {
 		for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
 			bh = &common->buffhds[i];
 			if (bh->inreq_busy)
@@ -2487,7 +2441,6 @@ static void handle_exception(struct fsg_common *common)
 	common->next_buffhd_to_fill = &common->buffhds[0];
 	common->next_buffhd_to_drain = &common->buffhds[0];
 	exception_req_tag = common->exception_req_tag;
-	new_config = common->new_config;
 	old_state = common->state;
 
 	if (old_state == FSG_STATE_ABORT_BULK_OUT)
@@ -2537,12 +2490,12 @@ static void handle_exception(struct fsg_common *common)
 		break;
 
 	case FSG_STATE_CONFIG_CHANGE:
-		rc = do_set_config(common, new_config);
+		do_set_interface(common, common->new_fsg);
 		break;
 
 	case FSG_STATE_EXIT:
 	case FSG_STATE_TERMINATED:
-		do_set_config(common, 0);		/* Free resources */
+		do_set_interface(common, NULL);		/* Free resources */
 		spin_lock_irq(&common->lock);
 		common->state = FSG_STATE_TERMINATED;	/* Stop the thread */
 		spin_unlock_irq(&common->lock);
@@ -2860,6 +2813,7 @@ buffhds_first_it:
 		goto error_release;
 	}
 	init_completion(&common->thread_notifier);
+	init_waitqueue_head(&common->fsg_wait);
 #undef OR
 
 
@@ -2954,9 +2908,19 @@ 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");
-	fsg_common_put(fsg->common);
+
+       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);
+
 	kfree(fsg);
 }