• Masahiro Yamada's avatar
    coccinelle: fix parallel build with CHECK=scripts/coccicheck · b96d06e6
    Masahiro Yamada authored
    
    [ Upstream commit d7059ca0 ]
    
    The command "make -j8 C=1 CHECK=scripts/coccicheck" produces
    lots of "coccicheck failed" error messages.
    
    Julia Lawall explained the Coccinelle behavior as follows:
    "The problem on the Coccinelle side is that it uses a subdirectory
    with the name of the semantic patch to store standard output and
    standard error for the different threads.  I didn't want to use a
    name with the pid, so that one could easily find this information
    while Coccinelle is running.  Normally the subdirectory is cleaned
    up when Coccinelle completes, so there is only one of them at a time.
    Maybe it is best to just add the pid.  There is the risk that these
    subdirectories will accumulate if Coccinelle crashes in a way such
    that they don't get cleaned up, but Coccinelle could print a warning
    if it detects this case, rather than failing."
    
    When scripts/coccicheck is used as CHECK tool and -j option is given
    to Make, the whole of build process runs in parallel.  So, multiple
    processes try to get access to the same subdirectory.
    
    I notice spatch creates the subdirectory only when it runs in parallel
    (i.e. --jobs <N> is given and <N> is greater than 1).
    
    Setting NPROC=1 is a reasonable solution; spatch does not create the
    subdirectory.  Besides, ONLINE=1 mode takes a single file input for
    each spatch invocation, so there is no reason to parallelize it in
    the first place.
    Signed-off-by: 's avatarMasahiro Yamada <yamada.masahiro@socionext.com>
    Acked-by: 's avatarJulia Lawall <Julia.Lawall@lip6.fr>
    Signed-off-by: 's avatarSasha Levin <alexander.levin@verizon.com>
    Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    b96d06e6