Commit e711b6e1 authored Nov 13, 2020 by Dan Carpenter Committed by Greg Kroah-Hartman Nov 24, 2020

ALSA: firewire: Clean up a locking issue in copy_resp_to_buf()



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: 555e8a8f ("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>

parent 3560603e

sound/firewire/fireworks/fireworks_transaction.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -124,7 +124,7 @@ copy_resp_to_buf(struct snd_efw efw, void data, size_t length, int *rcode)
	t = (struct snd_efw_transaction *)data;		t = (struct snd_efw_transaction *)data;
	length = min_t(size_t, be32_to_cpu(t->length) * sizeof(u32), length);		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)		if (efw->push_ptr < efw->pull_ptr)
	capacity = (unsigned int)(efw->pull_ptr - efw->push_ptr);		capacity = (unsigned int)(efw->pull_ptr - efw->push_ptr);
	@@ -191,7 +191,7 @@ handle_resp_for_user(struct fw_card *card, int generation, int source,

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

	static void		static void