Re: [PATCH 1/2] staging: rtl8192e: fix structure alignment

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Sep 25, 2023 at 09:11:14PM +0200, Philipp Hortmann wrote:
> On 9/25/23 17:54, Arnd Bergmann wrote:
> > From: Arnd Bergmann<arnd@arndb.de>
> > 
> > A recent cleanup changed the rtl8192e from using the custom misaligned
> > rtllib_hdr_3addr structure to the generic ieee80211_hdr_3addr definition
> > that enforces 16-bit structure alignment in memory.
> > 
> > This causes a gcc warning about conflicting alignment requirements:
> > 
> > drivers/staging/rtl8192e/rtllib.h:645:1: error: alignment 1 of 'struct rtllib_authentication' is less than 2 [-Werror=packed-not-aligned]
> >    645 | } __packed;
> >        | ^
> > rtllib.h:650:1: error: alignment 1 of 'struct rtllib_disauth' is less than 2 [-Werror=packed-not-aligned]
> > rtllib.h:655:1: error: alignment 1 of 'struct rtllib_disassoc' is less than 2 [-Werror=packed-not-aligned]
> > rtllib.h:661:1: error: alignment 1 of 'struct rtllib_probe_request' is less than 2 [-Werror=packed-not-aligned]
> > rtllib.h:672:1: error: alignment 1 of 'struct rtllib_probe_response' is less than 2 [-Werror=packed-not-aligned]
> > rtllib.h:683:1: error: alignment 1 of 'struct rtllib_assoc_request_frame' is less than 2 [-Werror=packed-not-aligned]
> > rtllib.h:691:1: error: alignment 1 of 'struct rtllib_assoc_response_frame' is less than 2 [-Werror=packed-not-aligned]
> > 
> > Change all of the structure definitions that include this one to also
> > use 16-bit alignment. This assumes that the objects are actually aligned
> > in memory, but that is normally guaranteed by the slab allocator already.
> > 
> > All members of the structure definitions are already 16-bit aligned,
> > so the layouts do not change. As an added benefit, 16-bit accesses are
> > generally faster than 8-bit accesses, so architectures without unaligned
> > load/store instructions can produce better code now by avoiding byte-wise
> > accesses.
> > 
> > Fixes: 71ddc43ed7c71 ("staging: rtl8192e: Replace struct rtllib_hdr_3addr in structs of rtllib.h")
> > Signed-off-by: Arnd Bergmann<arnd@arndb.de>
> 
> Hi,
> 
> thanks for your support.
> 
> your patches cannot be applied on top of the 24 patches which are in the
> queue. But may be Greg will not accept all of the patches send in.
> 
> Will see what happens when Greg sorts them out.
> 
> I tried your patches on hardware without the 24 patches send in. All OK
> 
> Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>

The first one didn't apply as it was already sent by someone else, but
the second one applied fine, thanks.

greg k-h