[dm-devel] [PATCH] dm: fix to_sector() for 32bit

[NeilBrown]

A dm-raid array with devices larger than 4GB won't assemble on
a 32 bit host since _check_data_dev_sectors() was added in 4.16.
This is because to_sector() treats its argument as an "unsigned long"
which is 32bits (4GB) on a 32bit host.  Using "unsigned long long"
is more correct.

Kernels as early as 4.2 can have other problems due to to_sector()
being used on the size of a device.

Fixes: 0cf4503174c1 ("dm raid: add support for the MD RAID0 personality")
cc: stable at vger.kernel.org (v4.2+)
Reported-and-tested-by: Guillaume Perréal <gperreal at free.fr>
Signed-off-by: NeilBrown <neil at brown.name>
---
 include/linux/device-mapper.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index e528baebad69..bee4bb9f81bc 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -609,7 +609,7 @@ do {									\
  */
 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
 
-static inline sector_t to_sector(unsigned long n)
+static inline sector_t to_sector(unsigned long long n)
 {
 	return (n >> SECTOR_SHIFT);
 }
-- 
2.14.0.rc0.dirty

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