From: Arnd Bergmann <arnd@arndb.de>
To: Vinod Koul <vinod.koul@intel.com>
Subject: Re: [PATCH] ALSA: compress: Fix the mismatch size of struc between share lib(32bit) and kernel(64bit)
Date: Tue, 17 Jun 2014 13:48:59 +0200
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Cc: Takashi Iwai <tiwai@suse.de>, "Wang, Xiaoming" <xiaoming.wang@intel.com>,
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On Tuesday 17 June 2014, Vinod Koul wrote:
> > Anyway, if you use the __packed attribute, best apply it only to
> > the individual __u64 member(s), not the entire struct, otherwise
> > you might change user space programs in a subtle way when the alignment
> > changes from 4 to 1 byte. 
>
> then wouldn't it make sense to call out the aligned as well to ensure that it is
> aligning to what we want. Then we should add aligned (4) everywhere as mostly we
> need 4 byte aligned here

If you want to be explicit, then just mark the entire structure as
attribute((packed,aligned(4))), not each individual member.

	Arnd
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