2 files changed, 74 insertions, 40 deletions

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index fa86b946dcd6..32cce029f65c 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -316,6 +316,27 @@ static const char fsg_string_interface[] = "Mass Storage";
 /*-------------------------------------------------------------------------*/
 
 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);
+
+	/* Called prior to ejection.  Negative return means error,
+	 * zero means to continue with ejection, positive means not to
+	 * eject. */
+	int (*pre_eject)(struct fsg_common *common,
+			 struct fsg_lun *lun, int num);
+	/* Called after ejection.  Negative return means error, zero
+	 * or positive is just a success. */
+	int (*post_eject)(struct fsg_common *common,
+			  struct fsg_lun *lun, int num);
+};
 
 
 /* Data shared by all the FSG instances. */
@@ -368,8 +389,8 @@ struct fsg_common {
 	struct completion	thread_notifier;
 	struct task_struct	*thread_task;
 
-	/* Callback function to call when thread exits. */
-	int			(*thread_exits)(struct fsg_common *common);
+	/* Callback functions. */
+	const struct fsg_operations	*ops;
 	/* Gadget's private data. */
 	void			*private_data;
 
@@ -393,12 +414,8 @@ struct fsg_config {
 	const char		*lun_name_format;
 	const char		*thread_name;
 
-	/* 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);
+	/* Callback functions. */
+	const struct fsg_operations	*ops;
 	/* Gadget's private data. */
 	void			*private_data;
 
@@ -434,6 +451,7 @@ static inline int __fsg_is_set(struct fsg_common *common,
 	if (common->fsg)
 		return 1;
 	ERROR(common, "common->fsg is NULL in %s at %u\n", func, line);
+	WARN_ON(1);
 	return 0;
 }
 
@@ -1392,43 +1410,55 @@ static int do_start_stop(struct fsg_common *common)
 	} else if (!curlun->removable) {
 		curlun->sense_data = SS_INVALID_COMMAND;
 		return -EINVAL;
-	}
-
-	loej = common->cmnd[4] & 0x02;
-	start = common->cmnd[4] & 0x01;
-
-	/* eject code from file_storage.c:do_start_stop() */
-
-	if ((common->cmnd[1] & ~0x01) != 0 ||	  /* Mask away Immed */
-		(common->cmnd[4] & ~0x03) != 0) { /* Mask LoEj, Start */
+	} else if ((common->cmnd[1] & ~0x01) != 0 || /* Mask away Immed */
+		   (common->cmnd[4] & ~0x03) != 0) { /* Mask LoEj, Start */
 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
 		return -EINVAL;
 	}
 
-	if (!start) {
-		/* Are we allowed to unload the media? */
-		if (curlun->prevent_medium_removal) {
-			LDBG(curlun, "unload attempt prevented\n");
-			curlun->sense_data = SS_MEDIUM_REMOVAL_PREVENTED;
-			return -EINVAL;
-		}
-		if (loej) {	/* Simulate an unload/eject */
-			up_read(&common->filesem);
-			down_write(&common->filesem);
-			fsg_lun_close(curlun);
-			up_write(&common->filesem);
-			down_read(&common->filesem);
-		}
-	} else {
+	loej  = common->cmnd[4] & 0x02;
+	start = common->cmnd[4] & 0x01;
 
-		/* Our emulation doesn't support mounting; the medium is
-		 * available for use as soon as it is loaded. */
+	/* Our emulation doesn't support mounting; the medium is
+	 * available for use as soon as it is loaded. */
+	if (start) {
 		if (!fsg_lun_is_open(curlun)) {
 			curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
 			return -EINVAL;
 		}
+		return 0;
 	}
-	return 0;
+
+	/* Are we allowed to unload the media? */
+	if (curlun->prevent_medium_removal) {
+		LDBG(curlun, "unload attempt prevented\n");
+		curlun->sense_data = SS_MEDIUM_REMOVAL_PREVENTED;
+		return -EINVAL;
+	}
+
+	if (!loej)
+		return 0;
+
+	/* Simulate an unload/eject */
+	if (common->ops && common->ops->pre_eject) {
+		int r = common->ops->pre_eject(common, curlun,
+					       curlun - common->luns);
+		if (unlikely(r < 0))
+			return r;
+		else if (r)
+			return 0;
+	}
+
+	up_read(&common->filesem);
+	down_write(&common->filesem);
+	fsg_lun_close(curlun);
+	up_write(&common->filesem);
+	down_read(&common->filesem);
+
+	return common->ops && common->ops->post_eject
+		? min(0, common->ops->post_eject(common, curlun,
+						 curlun - common->luns))
+		: 0;
 }
 
 
@@ -2607,7 +2637,8 @@ static int fsg_main_thread(void *common_)
 	common->thread_task = NULL;
 	spin_unlock_irq(&common->lock);
 
-	if (!common->thread_exits || common->thread_exits(common) < 0) {
+	if (!common->ops || !common->ops->thread_exits
+	 || common->ops->thread_exits(common) < 0) {
 		struct fsg_lun *curlun = common->luns;
 		unsigned i = common->nluns;
 
@@ -2683,6 +2714,7 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
 		common->free_storage_on_release = 0;
 	}
 
+	common->ops = cfg->ops;
 	common->private_data = cfg->private_data;
 
 	common->gadget = gadget;
@@ -2804,7 +2836,6 @@ buffhds_first_it:
 
 
 	/* Tell the thread to start working */
-	common->thread_exits = cfg->thread_exits;
 	common->thread_task =
 		kthread_create(fsg_main_thread, common,
 			       OR(cfg->thread_name, "file-storage"));
@@ -3100,8 +3131,8 @@ fsg_config_from_params(struct fsg_config *cfg,
 	cfg->product_name = 0;
 	cfg->release = 0xffff;
 
-	cfg->thread_exits = 0;
-	cfg->private_data = 0;
+	cfg->ops = NULL;
+	cfg->private_data = NULL;
 
 	/* Finalise */
 	cfg->can_stall = params->stall;
diff --git a/drivers/usb/gadget/mass_storage.c b/drivers/usb/gadget/mass_storage.c
index 2b11e2079823..306098f2d924 100644
--- a/drivers/usb/gadget/mass_storage.c
+++ b/drivers/usb/gadget/mass_storage.c
@@ -143,6 +143,9 @@ static int msg_thread_exits(struct fsg_common *common)
 
 static int __init msg_do_config(struct usb_configuration *c)
 {
+	static const struct fsg_operations ops = {
+		.thread_exits = msg_thread_exits,
+	};
 	static struct fsg_common common;
 
 	struct fsg_common *retp;
@@ -155,7 +158,7 @@ static int __init msg_do_config(struct usb_configuration *c)
 	}
 
 	fsg_config_from_params(&config, &mod_data);
-	config.thread_exits = msg_thread_exits;
+	config.ops = &ops;
 
 	retp = fsg_common_init(&common, c->cdev, &config);
 	if (IS_ERR(retp))