Commit 9286e24b authored by Jerry Zhang's avatar Jerry Zhang Committed by Felipe Balbi
Browse files

usb: gadget: f_midi: Use refcount when freeing f_midi_opts 



Currently, the midi function is not freed until it is
both removed from the config and released by the user.
Since the user could take a long time to release the
card, it's possible that the function could be unlinked
and thus f_midi_opts would be null when freeing f_midi.

Thus, refcount f_midi_opts and only free it when it is
unlinked and all f_midis have been freed.

Signed-off-by: default avatarJerry Zhang <zhangjerry@google.com>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
parent 7ecca2a4

drivers/usb/gadget/function/f_midi.c

+20 −6
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ static inline struct f_midi *func_to_midi(struct usb_function *f) 


static void f_midi_transmit(struct f_midi *midi);

static void f_midi_rmidi_free(struct snd_rawmidi *rmidi);

static void f_midi_free_inst(struct usb_function_instance *f);



DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);

DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1);
@@ -1102,7 +1103,7 @@ static ssize_t f_midi_opts_##name##_store(struct config_item *item, \ 
	u32 num;							\

									\

	mutex_lock(&opts->lock);					\

	if (opts->refcnt) {						\

	if (opts->refcnt > 1) {						\

		ret = -EBUSY;						\

		goto end;						\

	}								\
@@ -1157,7 +1158,7 @@ static ssize_t f_midi_opts_id_store(struct config_item *item, 
	char *c;



	mutex_lock(&opts->lock);

	if (opts->refcnt) {

	if (opts->refcnt > 1) {

		ret = -EBUSY;

		goto end;

	}
@@ -1198,14 +1199,22 @@ static const struct config_item_type midi_func_type = { 
static void f_midi_free_inst(struct usb_function_instance *f)

{

	struct f_midi_opts *opts;

	bool free = false;



	opts = container_of(f, struct f_midi_opts, func_inst);



	mutex_lock(&opts->lock);

	if (!--opts->refcnt) {

		free = true;

	}

	mutex_unlock(&opts->lock);



	if (free) {

		if (opts->id_allocated)

			kfree(opts->id);



		kfree(opts);

	}

}



static struct usb_function_instance *f_midi_alloc_inst(void)

{
@@ -1223,6 +1232,7 @@ static struct usb_function_instance *f_midi_alloc_inst(void) 
	opts->qlen = 32;

	opts->in_ports = 1;

	opts->out_ports = 1;

	opts->refcnt = 1;



	config_group_init_type_name(&opts->func_inst.group, "",

				    &midi_func_type);
@@ -1234,6 +1244,7 @@ static void f_midi_free(struct usb_function *f) 
{

	struct f_midi *midi;

	struct f_midi_opts *opts;

	bool free = false;



	midi = func_to_midi(f);

	opts = container_of(f->fi, struct f_midi_opts, func_inst);
@@ -1242,9 +1253,12 @@ static void f_midi_free(struct usb_function *f) 
		kfree(midi->id);

		kfifo_free(&midi->in_req_fifo);

		kfree(midi);

		--opts->refcnt;

		free = true;

	}

	mutex_unlock(&opts->lock);



	if (free)

		f_midi_free_inst(&opts->func_inst);

}



static void f_midi_rmidi_free(struct snd_rawmidi *rmidi)

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