Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] smc91x: avoid self-comparison warning | Date | Mon, 14 Mar 2016 23:45:12 +0100 |
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The smc91x driver defines a macro that compares its argument to itself, apparently to get a true result while using its argument to avoid a warning about unused local variables.
Unfortunately, this triggers a warning with gcc-6, as the comparison is obviously useless:
drivers/net/ethernet/smsc/smc91x.c: In function 'smc_hardware_send_pkt': drivers/net/ethernet/smsc/smc91x.c:563:14: error: self-comparison always evaluates to true [-Werror=tautological-compare] if (!smc_special_trylock(&lp->lock, flags)) {
This replaces the macro with another one that behaves similarly, with a cast to (void) to ensure the argument is used, and using a literal 'true' as its value.
Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/net/ethernet/smsc/smc91x.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/smsc/smc91x.c b/drivers/net/ethernet/smsc/smc91x.c index db7db8ac4ca3..c5ed27c54724 100644 --- a/drivers/net/ethernet/smsc/smc91x.c +++ b/drivers/net/ethernet/smsc/smc91x.c @@ -540,7 +540,7 @@ static inline void smc_rcv(struct net_device *dev) #define smc_special_lock(lock, flags) spin_lock_irqsave(lock, flags) #define smc_special_unlock(lock, flags) spin_unlock_irqrestore(lock, flags) #else -#define smc_special_trylock(lock, flags) (flags == flags) +#define smc_special_trylock(lock, flags) ((void)flags, true) #define smc_special_lock(lock, flags) do { flags = 0; } while (0) #define smc_special_unlock(lock, flags) do { flags = 0; } while (0) #endif -- 2.7.0
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