usb: gadget: f_midi: Use snd_card_free_when_closed with refcount

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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>

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Jerry Zhang 2017-08-14 14:14:51 -07:00 • committed by Felipe Balbi

parent 24cf34595d

commit 2d19cdc1cb

1 changed files with 17 additions and 5 deletions

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drivers/usb/gadget/function/f_midi.c

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