With ccache in combination with gcc-6, we get a harmless warning for the sfi subsystem, as ccache only sees the preprocessed source:
drivers/sfi/sfi_core.c: In function ‘sfi_map_table’: drivers/sfi/sfi_core.c:175:53: error: self-comparison always evaluates to true [-Werror=tautological-compare]
Using an inline function to do the comparison tells the compiler what is going on even for preprocessed files, and avoids the warning.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- drivers/sfi/sfi_core.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/sfi/sfi_core.c b/drivers/sfi/sfi_core.c index 296db7a69c27..a8f2313a2613 100644 --- a/drivers/sfi/sfi_core.c +++ b/drivers/sfi/sfi_core.c @@ -71,9 +71,12 @@
#include "sfi_core.h"
-#define ON_SAME_PAGE(addr1, addr2) \ - (((unsigned long)(addr1) & PAGE_MASK) == \ - ((unsigned long)(addr2) & PAGE_MASK)) +static inline bool on_same_page(unsigned long addr1, unsigned long addr2) +{ + return (addr1 & PAGE_MASK) == (addr2 & PAGE_MASK); +} + +#define ON_SAME_PAGE(addr1, addr2) on_same_page((unsigned long)addr1, (unsigned long)addr2) #define TABLE_ON_PAGE(page, table, size) (ON_SAME_PAGE(page, table) && \ ON_SAME_PAGE(page, table + size))