• Qian Cai's avatar
    asm-generic: fix -Wtype-limits compiler warnings · cbedfe11
    Qian Cai authored
    Commit d66acc39 ("bitops: Optimise get_order()") introduced a
    compilation warning because "rx_frag_size" is an "ushort" while
    PAGE_SHIFT here is 16.
    
    The commit changed the get_order() to be a multi-line macro where
    compilers insist to check all statements in the macro even when
    __builtin_constant_p(rx_frag_size) will return false as "rx_frag_size"
    is a module parameter.
    
    In file included from ./arch/powerpc/include/asm/page_64.h:107,
                     from ./arch/powerpc/include/asm/page.h:242,
                     from ./arch/powerpc/include/asm/mmu.h:132,
                     from ./arch/powerpc/include/asm/lppaca.h:47,
                     from ./arch/powerpc/include/asm/paca.h:17,
                     from ./arch/powerpc/include/asm/current.h:13,
                     from ./include/linux/thread_info.h:21,
                     from ./arch/powerpc/include/asm/processor.h:39,
                     from ./include/linux/prefetch.h:15,
                     from drivers/net/ethernet/emulex/benet/be_main.c:14:
    drivers/net/ethernet/emulex/benet/be_main.c: In function 'be_rx_cqs_create':
    ./include/asm-generic/getorder.h:54:9: warning: comparison is always
    true due to limited range of data type [-Wtype-limits]
       (((n) < (1UL << PAGE_SHIFT)) ? 0 :  \
             ^
    drivers/net/ethernet/emulex/benet/be_main.c:3138:33: note: in expansion
    of macro 'get_order'
      adapter->big_page_size = (1 << get_order(rx_frag_size)) * PAGE_SIZE;
                                     ^~~~~~~~~
    
    Fix it by moving all of this multi-line macro into a proper function,
    and killing __get_order() off.
    
    [akpm@linux-foundation.org: remove __get_order() altogether]
    [cai@lca.pw: v2]
      Link: http://lkml.kernel.org/r/1564000166-31428-1-git-send-email-cai@lca.pw
    Link: http://lkml.kernel.org/r/1563914986-26502-1-git-send-email-cai@lca.pw
    Fixes: d66acc39 ("bitops: Optimise get_order()")
    Signed-off-by: default avatarQian Cai <cai@lca.pw>
    Reviewed-by: default avatarNathan Chancellor <natechancellor@gmail.com>
    Cc: David S. Miller <davem@davemloft.net>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: David Howells <dhowells@redhat.com>
    Cc: Jakub Jelinek <jakub@redhat.com>
    Cc: Nick Desaulniers <ndesaulniers@google.com>
    Cc: Bill Wendling <morbo@google.com>
    Cc: James Y Knight <jyknight@google.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    cbedfe11
getorder.h 1.22 KB