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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH 5.10 031/103] cb710: avoid NULL pointer subtraction
Date:   Mon, 18 Oct 2021 15:24:07 +0200
Message-Id: <20211018132335.770620578@linuxfoundation.org>
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From: Arnd Bergmann <arnd@arndb.de>

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: 5f5bac8272be ("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>
---
 drivers/misc/cb710/sgbuf2.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/misc/cb710/sgbuf2.c
+++ b/drivers/misc/cb710/sgbuf2.c
@@ -47,7 +47,7 @@ static inline bool needs_unaligned_copy(
 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 	return false;
 #else
-	return ((ptr - NULL) & 3) != 0;
+	return ((uintptr_t)ptr & 3) != 0;
 #endif
 }