Messages in this thread | | | Subject | Re: [PATCH] carl9170: fix struct alignment conflict | From | Christian Lamparter <> | Date | Thu, 4 Feb 2021 18:22:01 +0100 |
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On 04/02/2021 17:29, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > Multiple structures in the carl9170 driver have alignment > impossible alignment constraints that gcc warns about when > building with 'make W=1': > > drivers/net/wireless/ath/carl9170/fwcmd.h:243:2: warning: alignment 1 of 'union <anonymous>' is less than 4 [-Wpacked-not-aligned] > drivers/net/wireless/ath/carl9170/wlan.h:373:1: warning: alignment 1 of 'struct ar9170_rx_frame_single' is less than 2 [-Wpacked-not-aligned] > > In the carl9170_cmd structure, multiple members that have an explicit > alignment requirement of four bytes are added into a union with explicit > byte alignment, but this in turn is part of a structure that also has > four-byte alignment. > > In the wlan.h header, multiple structures contain a ieee80211_hdr member > that is required to be two-byte aligned to avoid alignmnet faults when > processing network headers, but all members are forced to be byte-aligned > using the __packed tag at the end of the struct definition. > > In both cases, leaving out the packing does not change the internal > layout of the structure but changes the alignment constraint of the > structure itself. > > Change all affected structures to only apply packing where it does > not violate the alignment requirement of the contained structure. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christian Lamparter <chunkeey@gmail.com>
I've also applied this patch and a previous one dealing with VLAs to the firmware source at <https://github.com/chunkeey/carl9170fw>. I did a quick rebuilt and the same binary firmware was produced, so I think what's left is to update those shared firmware/driver headers some day...
Cheers, Christian
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