diff options
| author | Jerry Zhang <zhangjerry@google.com> | 2017-08-15 00:14:51 +0300 |
|---|---|---|
| committer | Felipe Balbi <felipe.balbi@linux.intel.com> | 2017-08-15 14:18:47 +0300 |
| commit | 2d19cdc1cb7ab00003fccb951d6199b8d8c9ac67 (patch) | |
| tree | a760bb4578621387011ecf34b5a2235904df2325 /drivers/usb/gadget/function | |
| parent | 24cf34595d560de0d8eccd6617b7ca5b4ef93d3e (diff) | |
| download | linux-2d19cdc1cb7ab00003fccb951d6199b8d8c9ac67.tar.xz | |
usb: gadget: f_midi: Use snd_card_free_when_closed with refcount
Currenly, f_midi_free uses snd_card_free, which will wait
until the user has released the sound card before
returning. However, if the user doesn't release the sound
card, then f_midi_free can block for an arbitrary amount
of time, which also blocks any gadget operations on that
thread.
Instead, we can use snd_card_free_when_closed which returns
before all handles are released. Since f_midi can be
accessed through rmidi if usb_put_function is called before
release_card_device, add refcounting to f_midi_free and
have rawmidi's private free call it. The f_midi memory
is only kfreed when usb_put_function and release_card_device
have both been called.
Signed-off-by: Jerry Zhang <zhangjerry@google.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Diffstat (limited to 'drivers/usb/gadget/function')
| -rw-r--r-- | drivers/usb/gadget/function/f_midi.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 94a2012b78f8..5d3d7941d2c2 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -98,6 +98,7 @@ struct f_midi { DECLARE_KFIFO_PTR(in_req_fifo, struct usb_request *); spinlock_t transmit_lock; unsigned int in_last_port; + unsigned char free_ref; struct gmidi_in_port in_ports_array[/* in_ports */]; }; @@ -108,6 +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); DECLARE_UAC_AC_HEADER_DESCRIPTOR(1); DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1); @@ -832,6 +834,8 @@ static int f_midi_register_card(struct f_midi *midi) SNDRV_RAWMIDI_INFO_INPUT | SNDRV_RAWMIDI_INFO_DUPLEX; rmidi->private_data = midi; + rmidi->private_free = f_midi_rmidi_free; + midi->free_ref++; /* * Yes, rawmidi OUTPUT = USB IN, and rawmidi INPUT = USB OUT. @@ -1233,14 +1237,21 @@ static void f_midi_free(struct usb_function *f) midi = func_to_midi(f); opts = container_of(f->fi, struct f_midi_opts, func_inst); - kfree(midi->id); mutex_lock(&opts->lock); - kfifo_free(&midi->in_req_fifo); - kfree(midi); - --opts->refcnt; + if (!--midi->free_ref) { + kfree(midi->id); + kfifo_free(&midi->in_req_fifo); + kfree(midi); + --opts->refcnt; + } mutex_unlock(&opts->lock); } +static void f_midi_rmidi_free(struct snd_rawmidi *rmidi) +{ + f_midi_free(rmidi->private_data); +} + static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f) { struct usb_composite_dev *cdev = f->config->cdev; @@ -1255,7 +1266,7 @@ static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f) card = midi->card; midi->card = NULL; if (card) - snd_card_free(card); + snd_card_free_when_closed(card); usb_free_all_descriptors(f); } @@ -1299,6 +1310,7 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi) midi->buflen = opts->buflen; midi->qlen = opts->qlen; midi->in_last_port = 0; + midi->free_ref = 1; status = kfifo_alloc(&midi->in_req_fifo, midi->qlen, GFP_KERNEL); if (status) |