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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Clemens Ladisch <clemens@ladisch.de>,
	Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: alsa-devel@alsa-project.org, kernel-janitors@vger.kernel.org,
	Takashi Iwai <tiwai@suse.com>
Subject: [PATCH] ALSA: firewire: Clean up a locking issue in copy_resp_to_buf()
Date: Fri, 13 Nov 2020 13:12:41 +0300
Message-ID: <20201113101241.GB168908@mwanda> (raw)

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

diff --git a/sound/firewire/fireworks/fireworks_transaction.c b/sound/firewire/fireworks/fireworks_transaction.c
index 0f533f5bd960..9f8c53b39f95 100644
--- 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, void *data, size_t length, int *rcode)
 	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 *card, int generation, int source,
 
 	copy_resp_to_buf(efw, data, length, rcode);
 end:
-	spin_unlock_irq(&instances_lock);
+	spin_unlock(&instances_lock);
 }
 
 static void
-- 
2.28.0


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Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-13 10:12 Dan Carpenter [this message]
2020-11-13 12:02 ` Takashi Sakamoto
2020-11-13 17:38 ` Takashi Iwai

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