• John Hubbard's avatar
    net: mvvp2: fix short frame size on s390 · 704e624f
    John Hubbard authored
    On s390, the following build warning occurs:
    
    drivers/net/ethernet/marvell/mvpp2/mvpp2.h:844:2: warning: overflow in
    conversion from 'long unsigned int' to 'int' changes value from
    '18446744073709551584' to '-32' [-Woverflow]
    844 |  ((total_size) - MVPP2_SKB_HEADROOM - MVPP2_SKB_SHINFO_SIZE)
    
    This happens because MVPP2_SKB_SHINFO_SIZE, which is 320 bytes (which is
    already 64-byte aligned) on some architectures, actually gets ALIGN'd up
    to 512 bytes in the s390 case.
    
    So then, when this is invoked:
    
        MVPP2_RX_MAX_PKT_SIZE(MVPP2_BM_SHORT_FRAME_SIZE)
    
    ...that turns into:
    
         704 - 224 - 512 == -32
    
    ...which is not a good frame size to end up with! The warning above is a
    bit lucky: it notices a signed/unsigned bad behavior here, which leads
    to the real problem of a frame that is too short for its contents.
    
    Increase MVPP2_BM_SHORT_FRAME_SIZE by 32 (from 704 to 736), which is
    just exactly big enough. (The other values can't readily be changed
    without causing a lot of other problems.)
    
    Fixes: 07dd0a7a ("mvpp2: add basic XDP support")
    Cc: Sven Auhagen <sven.auhagen@voleatech.de>
    Cc: Matteo Croce <mcroce@microsoft.com>
    Cc: David S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    704e624f
mvpp2.h 51.3 KB