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    Subject[PATCH 4.19 100/110] include/linux/pfn_t.h: force ~ to be parsed as an unary operator
    Date
    4.19-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Sebastien Boisvert <sebhtml@videotron.qc.ca>

    commit 4d54954a197175c0dcb3c82af0c0740d0c5f827a upstream.

    Tracing the event "fs_dax:dax_pmd_insert_mapping" with perf produces this
    warning:

    [fs_dax:dax_pmd_insert_mapping] unknown op '~'

    It is printed in process_op (tools/lib/traceevent/event-parse.c) because
    '~' is parsed as a binary operator.

    perf reads the format of fs_dax:dax_pmd_insert_mapping ("print fmt") from
    /sys/kernel/debug/tracing/events/fs_dax/dax_pmd_insert_mapping/format .

    The format contains:

    ~(((u64) ~(~(((1UL) << 12)-1)))
    ^
    \ interpreted as a binary operator by process_op().

    This part is generated in the declaration of the event class
    dax_pmd_insert_mapping_class in include/trace/events/fs_dax.h :

    __print_flags_u64(__entry->pfn_val & PFN_FLAGS_MASK, "|",
    PFN_FLAGS_TRACE),

    This patch adds a pair of parentheses in the declaration of PFN_FLAGS_MASK
    to make sure that '~' is parsed as a unary operator by perf.

    The part of the format that was problematic is now:

    ~(((u64) (~(~(((1UL) << 12)-1))))

    Now, all the '~' are parsed as unary operators.

    Link: http://lkml.kernel.org/r/20181021145939.8760-1-sebhtml@videotron.qc.ca
    Signed-off-by: Sebastien Boisvert <sebhtml@videotron.qc.ca>
    Acked-by: Dan Williams <dan.j.williams@intel.com>
    Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Ross Zwisler <zwisler@kernel.org>
    Cc: Elenie Godzaridis <arangradient@gmail.com>
    Cc: <stable@vger.kerenl.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    include/linux/pfn_t.h | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/include/linux/pfn_t.h
    +++ b/include/linux/pfn_t.h
    @@ -10,7 +10,7 @@
    * PFN_DEV - pfn is not covered by system memmap by default
    * PFN_MAP - pfn has a dynamic page mapping established by a device driver
    */
    -#define PFN_FLAGS_MASK (((u64) ~PAGE_MASK) << (BITS_PER_LONG_LONG - PAGE_SHIFT))
    +#define PFN_FLAGS_MASK (((u64) (~PAGE_MASK)) << (BITS_PER_LONG_LONG - PAGE_SHIFT))
    #define PFN_SG_CHAIN (1ULL << (BITS_PER_LONG_LONG - 1))
    #define PFN_SG_LAST (1ULL << (BITS_PER_LONG_LONG - 2))
    #define PFN_DEV (1ULL << (BITS_PER_LONG_LONG - 3))

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