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    Subject[PATCH 4.19 67/91] ALSA: firewire: Clean up a locking issue in copy_resp_to_buf()
    Date
    From: Dan Carpenter <dan.carpenter@oracle.com>

    commit 02a9c6ee4183af2e438454c55098b828a96085fb upstream.

    The spin_lock/unlock_irq() functions cannot be nested. The problem is
    that presumably we would want the IRQs to be re-enabled on the second
    call the spin_unlock_irq() but instead it will be enabled at the first
    call so IRQs will be enabled earlier than expected.

    In this situation the copy_resp_to_buf() function is only called from
    one function and it is called with IRQs disabled. We can just use
    the regular spin_lock/unlock() functions.

    Fixes: 555e8a8f7f14 ("ALSA: fireworks: Add command/response functionality into hwdep interface")
    Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
    Acked-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
    Cc: <stable@vger.kernel.org>
    Link: https://lore.kernel.org/r/20201113101241.GB168908@mwanda
    Signed-off-by: Takashi Iwai <tiwai@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    sound/firewire/fireworks/fireworks_transaction.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    --- a/sound/firewire/fireworks/fireworks_transaction.c
    +++ b/sound/firewire/fireworks/fireworks_transaction.c
    @@ -124,7 +124,7 @@ copy_resp_to_buf(struct snd_efw *efw, vo
    t = (struct snd_efw_transaction *)data;
    length = min_t(size_t, be32_to_cpu(t->length) * sizeof(u32), length);

    - spin_lock_irq(&efw->lock);
    + spin_lock(&efw->lock);

    if (efw->push_ptr < efw->pull_ptr)
    capacity = (unsigned int)(efw->pull_ptr - efw->push_ptr);
    @@ -191,7 +191,7 @@ handle_resp_for_user(struct fw_card *car

    copy_resp_to_buf(efw, data, length, rcode);
    end:
    - spin_unlock_irq(&instances_lock);
    + spin_unlock(&instances_lock);
    }

    static void

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