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Commit 9f825e74 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Boris Brezillon
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mtd: rawnand: Fix return type of __DIVIDE() when called with 32-bit 



The __DIVIDE() macro checks whether it is called with a 32-bit or 64-bit
dividend, to select the appropriate divide-and-round-up routine.
As the check uses the ternary operator, the result will always be
promoted to a type that can hold both results, i.e. unsigned long long.

When using this result in a division on a 32-bit system, this may lead
to link errors like:

    ERROR: "__udivdi3" [drivers/mtd/nand/raw/nand.ko] undefined!

Fix this by casting the result of the division to the type of the
dividend.

Fixes: 8878b126 ("mtd: nand: add ->exec_op() implementation")
Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@bootlin.com>
parent 90d61763

include/linux/mtd/rawnand.h

+11 −5
Original line number Diff line number Diff line
@@ -867,11 +867,17 @@ struct nand_op_instr { 
 * tBERS (during an erase) which all of them are u64 values that cannot be

 * divided by usual kernel macros and must be handled with the special

 * DIV_ROUND_UP_ULL() macro.

 *

 * Cast to type of dividend is needed here to guarantee that the result won't

 * be an unsigned long long when the dividend is an unsigned long (or smaller),

 * which is what the compiler does when it sees ternary operator with 2

 * different return types (picks the largest type to make sure there's no

 * loss).

 */

#define __DIVIDE(dividend, divisor) ({						\

	sizeof(dividend) == sizeof(u32) ?				\

	(__typeof__(dividend))(sizeof(dividend) <= sizeof(unsigned long) ?	\

			       DIV_ROUND_UP(dividend, divisor) :		\

		DIV_ROUND_UP_ULL(dividend, divisor);			\

			       DIV_ROUND_UP_ULL(dividend, divisor)); 		\

	})

#define PSEC_TO_NSEC(x) __DIVIDE(x, 1000)

#define PSEC_TO_MSEC(x) __DIVIDE(x, 1000000000)