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From: Richard Fitzgerald <rf@opensource.cirrus.com>
To: <vkoul@kernel.org>, <yung-chuan.liao@linux.intel.com>,
	<pierre-louis.bossart@linux.intel.com>, <sanyog.r.kale@intel.com>
Cc: <alsa-devel@alsa-project.org>, <linux-kernel@vger.kernel.org>,
	<patches@opensource.cirrus.com>,
	Richard Fitzgerald <rf@opensource.cirrus.com>
Subject: [PATCH 1/2] soundwire: bus: Prevent infinite loop in sdw_ch_mask_to_ch()
Date: Thu, 2 Feb 2023 15:42:11 +0000	[thread overview]
Message-ID: <20230202154212.1098736-2-rf@opensource.cirrus.com> (raw)
In-Reply-To: <20230202154212.1098736-1-rf@opensource.cirrus.com>

Define the ch_mask argument of sdw_ch_mask_to_ch() as an unsigned
so that the shift right is guaranteed to eventually make the
value of ch_mask==0.

Previously ch_mask was defined as a signed int, but a right
shift of a signed value preserves the sign bit. So if the sign
bit was 1, ch_mask would never become 0 and the for loop would
be infinite.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
 drivers/soundwire/bus.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h
index 7631ef5e71fb..28bedc919b78 100644
--- a/drivers/soundwire/bus.h
+++ b/drivers/soundwire/bus.h
@@ -160,7 +160,7 @@ int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave,
 		 u32 addr, size_t count, u16 dev_num, u8 flags, u8 *buf);
 
 /* Retrieve and return channel count from channel mask */
-static inline int sdw_ch_mask_to_ch(int ch_mask)
+static inline int sdw_ch_mask_to_ch(unsigned int ch_mask)
 {
 	int c = 0;
 
-- 
2.30.2


  reply	other threads:[~2023-02-02 16:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-02 15:42 [PATCH 0/2] soundwire: bus: Prevent infinite loop in sdw_ch_mask_to_ch() Richard Fitzgerald
2023-02-02 15:42 ` Richard Fitzgerald [this message]
2023-02-03 14:35   ` [PATCH 1/2] " Pierre-Louis Bossart
2023-02-03 16:18     ` Richard Fitzgerald
2023-03-15 13:43       ` Vinod Koul
2023-02-02 15:42 ` [PATCH 2/2] soundwire: bandwidth allocation: Use hweight32() to calculate set bits Richard Fitzgerald

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