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    Subject[PATCH 4.9 50/68] wireless: wext: avoid gcc -O3 warning
    Date
    From: Arnd Bergmann <arnd@arndb.de>

    [ Upstream commit e16119655c9e6c4aa5767cd971baa9c491f41b13 ]

    After the introduction of CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3,
    the wext code produces a bogus warning:

    In function 'iw_handler_get_iwstats',
    inlined from 'ioctl_standard_call' at net/wireless/wext-core.c:1015:9,
    inlined from 'wireless_process_ioctl' at net/wireless/wext-core.c:935:10,
    inlined from 'wext_ioctl_dispatch.part.8' at net/wireless/wext-core.c:986:8,
    inlined from 'wext_handle_ioctl':
    net/wireless/wext-core.c:671:3: error: argument 1 null where non-null expected [-Werror=nonnull]
    memcpy(extra, stats, sizeof(struct iw_statistics));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    In file included from arch/x86/include/asm/string.h:5,
    net/wireless/wext-core.c: In function 'wext_handle_ioctl':
    arch/x86/include/asm/string_64.h:14:14: note: in a call to function 'memcpy' declared here

    The problem is that ioctl_standard_call() sometimes calls the handler
    with a NULL argument that would cause a problem for iw_handler_get_iwstats.
    However, iw_handler_get_iwstats never actually gets called that way.

    Marking that function as noinline avoids the warning and leads
    to slightly smaller object code as well.

    Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    Link: https://lore.kernel.org/r/20200107200741.3588770-1-arnd@arndb.de
    Signed-off-by: Johannes Berg <johannes.berg@intel.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    net/wireless/wext-core.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c
    index 6250b1cfcde58..4bf0296a7c433 100644
    --- a/net/wireless/wext-core.c
    +++ b/net/wireless/wext-core.c
    @@ -659,7 +659,8 @@ struct iw_statistics *get_wireless_stats(struct net_device *dev)
    return NULL;
    }

    -static int iw_handler_get_iwstats(struct net_device * dev,
    +/* noinline to avoid a bogus warning with -O3 */
    +static noinline int iw_handler_get_iwstats(struct net_device * dev,
    struct iw_request_info * info,
    union iwreq_data * wrqu,
    char * extra)
    --
    2.20.1


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