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bwi: Fix clang 14 warning about possible unaligned access

Description

bwi: Fix clang 14 warning about possible unaligned access

On architectures with strict alignment requirements (e.g. arm), clang 14
warns about a packed struct which encloses a non-packed union:

In file included from sys/dev/bwi/bwimac.c:79:
sys/dev/bwi/if_bwivar.h:308:7: error: field iv_val within 'struct bwi_fw_iv' is less aligned than 'union (unnamed union at sys/dev/bwi/if_bwivar.h:305:2)' and is usually due to 'struct bwi_fw_iv' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
} iv_val;

				^

It appears to help if you also add __packed to the inner union (i.e.
iv_val). No change to the layout is intended.

MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D34196

(cherry picked from commit 09d0a0fbe859e3fc7bbff0cf48c389b5e55b9e00)

Details

Provenance
dimAuthored on Feb 7 2022, 8:59 PM
Differential Revision
D34196: bwi: Fix clang 14 warning about possible unaligned access
Parents
rG2a454b54bfbc: Fix the build after commit 5fa005e91560785dad5183db080209447afde3c2
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