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    SubjectRe: I need help with a sparse warning
    Roland Dreier wrote:
    > > In file drivers/net/wireless/p54/p54common.c, the statement
    > >
    > > priv->rx_mtu = (size_t) le16_to_cpu((__le16)bootrec->data[10]);
    > [I don't see this code in Linus's tree]

    It is in wireless-testing.

    > the code in question looks buggy to me. Since bootrec->data[10] is u32,
    > casting it to a 16-bit type is going to take a different 2 bytes out of
    > the 4 bytes depending on the endianness of the system the driver is
    > built for. And I assume you are parsing some fixed-layout thing that
    > the firmware is giving you or something like that.
    > I would guess you want something like:
    > priv->rx_mtu = le16_to_cpu(((__force __le16 *) bootrec->data)[20]);
    > (__force is what shuts up sparse, and as far as I can see, the size_t
    > cast is useless, since the result will be promoted anyway)

    Yes, that one works. As you suspected, this section is parsing data
    from the firmware.

    When I started, there were 18 sparse warnings, and a number of them
    were accesses of little-endian variables without an appropriate
    leXX_to_cpu() conversion. Obviously, this code has never been tested
    on a big-endian machine.



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