Messages in this thread Patch in this message | | | From | Geert Uytterhoeven <> | Subject | [PATCH] mtd: nand: Fix return type of __DIVIDE() when called with 32-bit | Date | Mon, 14 May 2018 12:49:37 +0200 |
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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 64-bit division to the type of the dividend.
Fixes: 8878b126df769831 ("mtd: nand: add ->exec_op() implementation") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> --- This fixes the root cause of the link failure seen with m68k/allmodconfig since commit 3057fcef385348fe ("mtd: rawnand: Make sure we wait tWB before polling the STATUS reg").
An alternative mitigation was posted as "[PATCH] m68k: Implement ndelay() as an inline function to force type checking/casting" (https://lkml.org/lkml/2018/5/13/102). --- include/linux/mtd/rawnand.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h index 5dad59b312440a9c..d06dc428ea0102ae 100644 --- a/include/linux/mtd/rawnand.h +++ b/include/linux/mtd/rawnand.h @@ -871,7 +871,7 @@ struct nand_op_instr { #define __DIVIDE(dividend, divisor) ({ \ sizeof(dividend) == sizeof(u32) ? \ DIV_ROUND_UP(dividend, divisor) : \ - DIV_ROUND_UP_ULL(dividend, divisor); \ + (__typeof__(dividend))DIV_ROUND_UP_ULL(dividend, divisor); \ }) #define PSEC_TO_NSEC(x) __DIVIDE(x, 1000) #define PSEC_TO_MSEC(x) __DIVIDE(x, 1000000000) -- 2.7.4
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