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    SubjectRe: {PATCH] fix __packed in exported kernel headers
    On 2011.06.24 at 18:33 +0200, Arnd Bergmann wrote:
    > On Friday 24 June 2011, Markus Trippelsdorf wrote:
    > > checkpatch.pl warns about using __attribute__((packed)) in kernel
    > > headers: "__packed is preferred over __attribute__((packed))". If one
    > > follows that advice it could cause problems in the exported header
    > > files, because the outside world doesn't know about this shortcut.
    > >
    > > For example busybox will fail to compile:
    > > CC miscutils/ubi_attach_detach.o
    > > In file included from miscutils/ubi_attach_detach.c:27:0:
    > > /usr/include/mtd/ubi-user.h:330:3: error: conflicting types for ‘__packed’
    > > /usr/include/mtd/ubi-user.h:314:3: note: previous declaration of ‘__packed’ was here
    > > ...
    > >
    > > Fix the problem by substituting __packed with __attribute__((packed)) in
    > > the header_install.pl script.
    >
    > No objections to the patch, but it should probably be noted that user
    > visible data structures should ideally not have any attributes, because
    > that requires building all applictions using that interface with gcc.
    >
    > We generally try to add no such requirements on user applications.

    Both icc and clang support __attribute__((packed)).

    And a rough count shows:
    % grep -R "packed" /usr/src/linux/usr/include | wc -l
    262

    --
    Markus
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