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authorAlistair Popple <apopple@nvidia.com>2021-11-10 20:32:40 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-11 09:34:35 -0800
commitab09243aa95a72bac5c71e852773de34116f8d0f (patch)
tree825f51109c310ac95b1bf5278394badbec8fd6dc /lib
parent0ef024621417fa3fcdeb2c3320f90ee34e18a5d9 (diff)
downloadlwn-ab09243aa95a72bac5c71e852773de34116f8d0f.tar.gz
lwn-ab09243aa95a72bac5c71e852773de34116f8d0f.zip
mm/migrate.c: remove MIGRATE_PFN_LOCKED
MIGRATE_PFN_LOCKED is used to indicate to migrate_vma_prepare() that a source page was already locked during migrate_vma_collect(). If it wasn't then the a second attempt is made to lock the page. However if the first attempt failed it's unlikely a second attempt will succeed, and the retry adds complexity. So clean this up by removing the retry and MIGRATE_PFN_LOCKED flag. Destination pages are also meant to have the MIGRATE_PFN_LOCKED flag set, but nothing actually checks that. Link: https://lkml.kernel.org/r/20211025041608.289017-1-apopple@nvidia.com Signed-off-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ben Skeggs <bskeggs@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/test_hmm.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index c259842f6d44..e2ce8f9b7605 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -613,8 +613,7 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
*/
rpage->zone_device_data = dmirror;
- *dst = migrate_pfn(page_to_pfn(dpage)) |
- MIGRATE_PFN_LOCKED;
+ *dst = migrate_pfn(page_to_pfn(dpage));
if ((*src & MIGRATE_PFN_WRITE) ||
(!spage && args->vma->vm_flags & VM_WRITE))
*dst |= MIGRATE_PFN_WRITE;
@@ -1137,7 +1136,7 @@ static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
lock_page(dpage);
xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
copy_highpage(dpage, spage);
- *dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
+ *dst = migrate_pfn(page_to_pfn(dpage));
if (*src & MIGRATE_PFN_WRITE)
*dst |= MIGRATE_PFN_WRITE;
}