usb: gadget: mass_storage: Use static array for luns

This patch replace dynamicly allocated luns array with static one.
This simplifies the code of mass storage function and modules.

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>

1 files changed, 46 insertions, 81 deletions

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 9870913e34bf..04c3bb6e9dcd 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -279,9 +279,8 @@ struct fsg_common {
 	int			cmnd_size;
 	u8			cmnd[MAX_COMMAND_SIZE];
 
-	unsigned int		nluns;
 	unsigned int		lun;
-	struct fsg_lun		**luns;
+	struct fsg_lun		*luns[FSG_MAX_LUNS];
 	struct fsg_lun		*curlun;
 
 	unsigned int		bulk_out_maxpacket;
@@ -490,6 +489,16 @@ static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
 	spin_unlock(&common->lock);
 }
 
+static int _fsg_common_get_max_lun(struct fsg_common *common)
+{
+	int i = ARRAY_SIZE(common->luns) - 1;
+
+	while (i >= 0 && !common->luns[i])
+		--i;
+
+	return i;
+}
+
 static int fsg_setup(struct usb_function *f,
 		     const struct usb_ctrlrequest *ctrl)
 {
@@ -533,7 +542,7 @@ static int fsg_setup(struct usb_function *f,
 				w_length != 1)
 			return -EDOM;
 		VDBG(fsg, "get max LUN\n");
-		*(u8 *)req->buf = fsg->common->nluns - 1;
+		*(u8 *)req->buf = _fsg_common_get_max_lun(fsg->common);
 
 		/* Respond with data/status */
 		req->length = min((u16)1, w_length);
@@ -2131,8 +2140,9 @@ static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
 	}
 
 	/* Is the CBW meaningful? */
-	if (cbw->Lun >= FSG_MAX_LUNS || cbw->Flags & ~US_BULK_FLAG_IN ||
-			cbw->Length <= 0 || cbw->Length > MAX_COMMAND_SIZE) {
+	if (cbw->Lun >= ARRAY_SIZE(common->luns) ||
+	    cbw->Flags & ~US_BULK_FLAG_IN || cbw->Length <= 0 ||
+	    cbw->Length > MAX_COMMAND_SIZE) {
 		DBG(fsg, "non-meaningful CBW: lun = %u, flags = 0x%x, "
 				"cmdlen %u\n",
 				cbw->Lun, cbw->Flags, cbw->Length);
@@ -2159,7 +2169,7 @@ static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
 	if (common->data_size == 0)
 		common->data_dir = DATA_DIR_NONE;
 	common->lun = cbw->Lun;
-	if (common->lun < common->nluns)
+	if (common->lun < ARRAY_SIZE(common->luns))
 		common->curlun = common->luns[common->lun];
 	else
 		common->curlun = NULL;
@@ -2307,7 +2317,7 @@ reset:
 	}
 
 	common->running = 1;
-	for (i = 0; i < common->nluns; ++i)
+	for (i = 0; i < ARRAY_SIZE(common->luns); ++i)
 		if (common->luns[i])
 			common->luns[i]->unit_attention_data =
 				SS_RESET_OCCURRED;
@@ -2409,7 +2419,7 @@ static void handle_exception(struct fsg_common *common)
 	if (old_state == FSG_STATE_ABORT_BULK_OUT)
 		common->state = FSG_STATE_STATUS_PHASE;
 	else {
-		for (i = 0; i < common->nluns; ++i) {
+		for (i = 0; i < ARRAY_SIZE(common->luns); ++i) {
 			curlun = common->luns[i];
 			if (!curlun)
 				continue;
@@ -2453,7 +2463,7 @@ static void handle_exception(struct fsg_common *common)
 		 * a waste of time.  Ditto for the INTERFACE_CHANGE and
 		 * CONFIG_CHANGE cases.
 		 */
-		/* for (i = 0; i < common->nluns; ++i) */
+		/* for (i = 0; i < common->ARRAY_SIZE(common->luns); ++i) */
 		/*	if (common->luns[i]) */
 		/*		common->luns[i]->unit_attention_data = */
 		/*			SS_RESET_OCCURRED;  */
@@ -2552,12 +2562,11 @@ static int fsg_main_thread(void *common_)
 
 	if (!common->ops || !common->ops->thread_exits
 	 || common->ops->thread_exits(common) < 0) {
-		struct fsg_lun **curlun_it = common->luns;
-		unsigned i = common->nluns;
+		int i;
 
 		down_write(&common->filesem);
-		for (; i--; ++curlun_it) {
-			struct fsg_lun *curlun = *curlun_it;
+		for (i = 0; i < ARRAY_SIZE(common->luns); --i) {
+			struct fsg_lun *curlun = common->luns[i];
 			if (!curlun || !fsg_lun_is_open(curlun))
 				continue;
 
@@ -2676,6 +2685,7 @@ static struct fsg_common *fsg_common_setup(struct fsg_common *common)
 	init_completion(&common->thread_notifier);
 	init_waitqueue_head(&common->fsg_wait);
 	common->state = FSG_STATE_TERMINATED;
+	memset(common->luns, 0, sizeof(common->luns));
 
 	return common;
 }
@@ -2764,42 +2774,10 @@ static void _fsg_common_remove_luns(struct fsg_common *common, int n)
 
 void fsg_common_remove_luns(struct fsg_common *common)
 {
-	_fsg_common_remove_luns(common, common->nluns);
+	_fsg_common_remove_luns(common, ARRAY_SIZE(common->luns));
 }
 EXPORT_SYMBOL_GPL(fsg_common_remove_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(FSG_MAX_LUNS, sizeof(*curlun), GFP_KERNEL);
-	if (unlikely(!curlun))
-		return -ENOMEM;
-
-	if (common->luns)
-		fsg_common_free_luns(common);
-
-	common->luns = curlun;
-	common->nluns = nluns;
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(fsg_common_set_nluns);
-
 void fsg_common_set_ops(struct fsg_common *common,
 			const struct fsg_operations *ops)
 {
@@ -2881,7 +2859,7 @@ int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg,
 	char *pathbuf, *p;
 	int rc = -ENOMEM;
 
-	if (!common->nluns || !common->luns)
+	if (id >= ARRAY_SIZE(common->luns))
 		return -ENODEV;
 
 	if (common->luns[id])
@@ -2965,14 +2943,16 @@ 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) {
+	fsg_common_remove_luns(common);
+
+	for (i = 0; i < cfg->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);
+	pr_info("Number of LUNs=%d\n", cfg->nluns);
 
 	return 0;
 
@@ -3021,6 +3001,7 @@ EXPORT_SYMBOL_GPL(fsg_common_run_thread);
 static void fsg_common_release(struct kref *ref)
 {
 	struct fsg_common *common = container_of(ref, struct fsg_common, ref);
+	int i;
 
 	/* If the thread isn't already dead, tell it to exit now */
 	if (common->state != FSG_STATE_TERMINATED) {
@@ -3028,22 +3009,14 @@ static void fsg_common_release(struct kref *ref)
 		wait_for_completion(&common->thread_notifier);
 	}
 
-	if (likely(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_it) {
-			struct fsg_lun *lun = *lun_it;
-			if (!lun)
-				continue;
-			fsg_lun_close(lun);
+	for (i = 0; i < ARRAY_SIZE(common->luns); ++i) {
+		struct fsg_lun *lun = common->luns[i];
+		if (!lun)
+			continue;
+		fsg_lun_close(lun);
 		if (device_is_registered(&lun->dev))
-				device_unregister(&lun->dev);
-			kfree(lun);
-		}
-
-		kfree(common->luns);
+			device_unregister(&lun->dev);
+		kfree(lun);
 	}
 
 	_fsg_common_free_buffers(common->buffhds, common->fsg_num_buffers);
@@ -3057,6 +3030,7 @@ static void fsg_common_release(struct kref *ref)
 static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct fsg_dev		*fsg = fsg_from_func(f);
+	struct fsg_common	*common = fsg->common;
 	struct usb_gadget	*gadget = c->cdev->gadget;
 	int			i;
 	struct usb_ep		*ep;
@@ -3064,6 +3038,13 @@ static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
 	int			ret;
 	struct fsg_opts		*opts;
 
+	/* Don't allow to bind if we don't have at least one LUN */
+	ret = _fsg_common_get_max_lun(common);
+	if (ret < 0) {
+		pr_err("There should be at least one LUN.\n");
+		return -EINVAL;
+	}
+
 	opts = fsg_opts_from_func_inst(f->fi);
 	if (!opts->no_configfs) {
 		ret = fsg_common_set_cdev(fsg->common, c->cdev,
@@ -3517,14 +3498,11 @@ static struct usb_function_instance *fsg_alloc_inst(void)
 		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;
+		goto release_opts;
 
 	pr_info(FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
 
@@ -3547,8 +3525,6 @@ static struct usb_function_instance *fsg_alloc_inst(void)
 
 release_buffers:
 	fsg_common_free_buffers(opts->common);
-release_luns:
-	kfree(opts->common->luns);
 release_opts:
 	kfree(opts);
 	return ERR_PTR(rc);
@@ -3574,23 +3550,12 @@ 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;
-	unsigned nluns, i;
 
 	fsg = kzalloc(sizeof(*fsg), GFP_KERNEL);
 	if (unlikely(!fsg))
 		return ERR_PTR(-ENOMEM);
 
 	mutex_lock(&opts->lock);
-	if (!opts->refcnt) {
-		for (nluns = i = 0; i < FSG_MAX_LUNS; ++i)
-			if (common->luns[i])
-				nluns = i + 1;
-		if (!nluns)
-			pr_warn("No LUNS defined, continuing anyway\n");
-		else
-			common->nluns = nluns;
-		pr_info("Number of LUNs=%u\n", common->nluns);
-	}
 	opts->refcnt++;
 	mutex_unlock(&opts->lock);