[PATCH 5.4 117/158] ALSA: firewire: Clean up a locking issue in copy_resp_to_buf()

Greg Kroah-Hartman
2020-11-23T12:39:33Z

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
@@ -123,7 +123,7 @@ 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);
@@ -190,7 +190,7 @@ 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