[PATCH] [v2] wifi: b43: fix incorrect __packed annotation

[PATCH] [v2] wifi: b43: fix incorrect __packed annotation

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

clang warns about an unpacked structure inside of a packed one:

drivers/net/wireless/broadcom/b43/b43.h:654:4: error: field data within 'struct b43_iv' is less aligned than 'union (unnamed union at /home/arnd/arm-soc/drivers/net/wireless/broadcom/b43/b43.h:651:2)' and is usually due to 'struct b43_iv' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]

The problem here is that the anonymous union has the default alignment
from its members, apparently because the original author mixed up the
placement of the __packed attribute by placing it next to the struct
member rather than the union definition. As the struct itself is
also marked as __packed, there is no need to mark its members, so just
move the annotation to the inner type instead.

As Michael noted, the same problem is present in b43legacy, so
change both at the same time.

Acked-by: Michael Büsch <m@bues.ch>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Link: https://lore.kernel.org/oe-kbuild-all/202305160749.ay1HAoyP-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/broadcom/b43/b43.h             | 2 +-
 drivers/net/wireless/broadcom/b43legacy/b43legacy.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/broadcom/b43/b43.h b/drivers/net/wireless/broadcom/b43/b43.h
index 9fc7c088a539..67b4bac048e5 100644
--- a/drivers/net/wireless/broadcom/b43/b43.h
+++ b/drivers/net/wireless/broadcom/b43/b43.h
@@ -651,7 +651,7 @@ struct b43_iv {
 	union {
 		__be16 d16;
 		__be32 d32;
-	} data __packed;
+	} __packed data;
 } __packed;
 
 
diff --git a/drivers/net/wireless/broadcom/b43legacy/b43legacy.h b/drivers/net/wireless/broadcom/b43legacy/b43legacy.h
index 6b0cec467938..f49365d14619 100644
--- a/drivers/net/wireless/broadcom/b43legacy/b43legacy.h
+++ b/drivers/net/wireless/broadcom/b43legacy/b43legacy.h
@@ -379,7 +379,7 @@ struct b43legacy_iv {
 	union {
 		__be16 d16;
 		__be32 d32;
-	} data __packed;
+	} __packed data;
 } __packed;
 
 #define B43legacy_PHYMODE(phytype)	(1 << (phytype))
-- 
2.39.2


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Re: [PATCH] [v2] wifi: b43: fix incorrect __packed annotation

[Kalle Valo]

Arnd Bergmann <arnd@kernel.org> wrote:

> From: Arnd Bergmann <arnd@arndb.de>
> 
> clang warns about an unpacked structure inside of a packed one:
> 
> drivers/net/wireless/broadcom/b43/b43.h:654:4: error: field data within 'struct b43_iv' is less aligned than 'union (unnamed union at /home/arnd/arm-soc/drivers/net/wireless/broadcom/b43/b43.h:651:2)' and is usually due to 'struct b43_iv' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
> 
> The problem here is that the anonymous union has the default alignment
> from its members, apparently because the original author mixed up the
> placement of the __packed attribute by placing it next to the struct
> member rather than the union definition. As the struct itself is
> also marked as __packed, there is no need to mark its members, so just
> move the annotation to the inner type instead.
> 
> As Michael noted, the same problem is present in b43legacy, so
> change both at the same time.
> 
> Acked-by: Michael Büsch <m@bues.ch>
> Reported-by: kernel test robot <lkp@intel.com>
> Reviewed-by: Simon Horman <simon.horman@corigine.com>
> Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
> Link: https://lore.kernel.org/oe-kbuild-all/202305160749.ay1HAoyP-lkp@intel.com/
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Patch applied to wireless.git, thanks.

212457ccbd60 wifi: b43: fix incorrect __packed annotation

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20230516183442.536589-1-arnd@kernel.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches


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