cb710: avoid NULL pointer subtraction

commit 42641042c10c757fe10cc09088cf3f436cec5007 upstream.

clang-14 complains about an unusual way of converting a pointer to
an integer:

drivers/misc/cb710/sgbuf2.c:50:15: error: performing pointer subtraction with a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction]
        return ((ptr - NULL) & 3) != 0;

Replace this with a normal cast to uintptr_t.

Fixes: c87ff62df22b ("mmc: Driver for CB710/720 memory card reader (MMC part)")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210927121408.939246-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/cb710/sgbuf2.c b/drivers/misc/cb710/sgbuf2.c
index dfd2969e362890e01d8c145e80c376a3ebbde624..d52e079bb324e992410e974ccf7b41fc90ffe614 100644 (file)
--- a/drivers/misc/cb710/sgbuf2.c
+++ b/drivers/misc/cb710/sgbuf2.c
@@ -47,7 +47,7 @@ static inline bool needs_unaligned_copy(const void *ptr)
 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
        return false;
 #else
-       return ((ptr - NULL) & 3) != 0;
+       return ((uintptr_t)ptr & 3) != 0;
 #endif
 }