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From:   Brian Gix <brian.gix@intel.com>
To:     linux-bluetooth@vger.kernel.org
Cc:     luiz.von.dentz@gmail.com, brian.gix@intel.com
Subject: [PATCH BlueZ 1/2] core: make bt_uuid_hash() portable across archs
Date:   Wed, 29 Jun 2022 12:44:31 -0700
Message-Id: <20220629194432.20229-1-brian.gix@intel.com>
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Precedence: bulk

bt_uuid_t is defined as a byte array, so it can cause alignment errors
on some architectures, when the two 64 bit halves are treated as u64s.
This patch ensures proper alignment across all architectures.

Fixes:
src/adapter.c: In function ‘bt_uuid_hash’:
src/adapter.c:3617:8: error: cast increases required alignment of target type [-Werror=cast-align]
  val = (uint64_t *)&uuid_128.value.u128;
        ^
cc1: all warnings being treated as errors
---
 src/adapter.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/adapter.c b/src/adapter.c
index afefa1d5d..c8b3d27a7 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -3607,16 +3607,14 @@ static void add_uuid_to_uuid_set(void *data, void *user_data)
 static guint bt_uuid_hash(gconstpointer key)
 {
 	const bt_uuid_t *uuid = key;
-	bt_uuid_t uuid_128;
-	uint64_t *val;
+	uint64_t uuid_128[2];
 
 	if (!uuid)
 		return 0;
 
-	bt_uuid_to_uuid128(uuid, &uuid_128);
-	val = (uint64_t *)&uuid_128.value.u128;
+	bt_uuid_to_uuid128(uuid, (bt_uuid_t *)uuid_128);
 
-	return g_int64_hash(val) ^ g_int64_hash(val+1);
+	return g_int64_hash(uuid_128) ^ g_int64_hash(uuid_128+1);
 }
 
 static gboolean bt_uuid_equal(gconstpointer v1, gconstpointer v2)
-- 
2.36.1