summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorGeert Uytterhoeven <geert@linux-m68k.org>2018-05-14 12:49:37 +0200
committerBoris Brezillon <boris.brezillon@bootlin.com>2018-05-15 14:40:34 +0200
commit9f825e74d761c13b0cfaa5f65344d64ff970e252 (patch)
tree27e468bb03044278cad53d29adae9076e0f536b1
parent90d617633368ab97a2c7571c6e66dad54f39228d (diff)
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: 8878b126df769831 ("mtd: nand: add ->exec_op() implementation") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
-rw-r--r--include/linux/mtd/rawnand.h16
1 files changed, 11 insertions, 5 deletions
diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
index 5dad59b31244..17c919436f48 100644
--- a/include/linux/mtd/rawnand.h
+++ b/include/linux/mtd/rawnand.h
@@ -867,12 +867,18 @@ 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) ? \
- DIV_ROUND_UP(dividend, divisor) : \
- DIV_ROUND_UP_ULL(dividend, divisor); \
- })
+#define __DIVIDE(dividend, divisor) ({ \
+ (__typeof__(dividend))(sizeof(dividend) <= sizeof(unsigned long) ? \
+ DIV_ROUND_UP(dividend, divisor) : \
+ DIV_ROUND_UP_ULL(dividend, divisor)); \
+ })
#define PSEC_TO_NSEC(x) __DIVIDE(x, 1000)
#define PSEC_TO_MSEC(x) __DIVIDE(x, 1000000000)