Thread (3 messages) 3 messages, 2 authors, 2022-06-23

Re: [PATCH] md/raid5: Fix divide type in raid5_make_request()

From: Song Liu <song@kernel.org>
Date: 2022-06-23 17:59:54
Also in: lkml

On Thu, Jun 23, 2022 at 9:56 AM Logan Gunthorpe [off-list ref] wrote:
0day reports a build failure on the hexagon architecture:

  ld.lld: error: undefined symbol: __hexagon_udivdi3
     referenced by raid5.c
        md/raid5.o:(raid5_make_request) in archive drivers/built-in.a
     referenced by raid5.c
        md/raid5.o:(raid5_make_request) in archive drivers/built-in.a
     did you mean: __hexagon_udivsi3
        defined in: arch/hexagon/built-in.a(lib/udivsi3.o)

This is caused by using DIV_ROUND_UP on a sector_t type.

The actual value is known to be less than 256 so a wide 64bit divide
here is not desirable. Thus cast the argument to an int to ensure it
uses a 32bit divide.
I force pushed an update that uses DIV_ROUND_UP_SECTOR_T instead.
I guess that should also work?

Thanks,
Song
quoted hunk ↗ jump to hunk
Fixes: 681fb14a7100 ("md/raid5: Pivot raid5_make_request()")
Reported-by: kernel test robot <redacted>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 drivers/md/raid5.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 5723a497108a..9d25696b793d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6091,7 +6091,7 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
        bi->bi_next = NULL;

        bitmap_set(ctx.sectors_to_do, 0,
-                  DIV_ROUND_UP(ctx.last_sector - logical_sector,
+                  DIV_ROUND_UP((int)(ctx.last_sector - logical_sector),
                                RAID5_STRIPE_SECTORS(conf)));

        pr_debug("raid456: %s, logical %llu to %llu\n", __func__,
base-commit: 57c19f921f8081c1a9444dc7f3f6b3ea43fe612e
--
2.30.2
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