Commit 57294a97 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Andrew Morton
Browse files

mm/migrate_device: remove dead migration entry check in migrate_vma_collect_huge_pmd() 

The softleaf_is_migration() check is unreachable as entries that are not
device_private are filtered out.  Similarly, the PTE-level equivalent in
migrate_vma_collect_pmd() skips migration entries.

This dead branch also contained a double spin_unlock(ptl) bug.

Link: https://lore.kernel.org/20260212014611.416695-1-dave@stgolabs.net


Fixes: a30b48bf ("mm/migrate_device: implement THP migration of zone device pages")
Signed-off-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Suggested-by: default avatarMatthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarAlistair Popple <apopple@nvidia.com>
Acked-by: default avatarBalbir Singh <balbirs@nvidia.com>
Acked-by: default avatarDavid Hildenbrand (Arm) <david@kernel.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent d432e884

mm/migrate_device.c

+0 −6
Original line number Diff line number Diff line
@@ -175,12 +175,6 @@ static int migrate_vma_collect_huge_pmd(pmd_t *pmdp, unsigned long start, 
			return migrate_vma_collect_skip(start, end, walk);

		}



		if (softleaf_is_migration(entry)) {

			softleaf_entry_wait_on_locked(entry, ptl);

			spin_unlock(ptl);

			return -EAGAIN;

		}



		if (softleaf_is_device_private_write(entry))

			write = MIGRATE_PFN_WRITE;

	} else {