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authorAlistair Popple <[email protected]>2022-11-11 11:51:35 +1100
committerAndrew Morton <[email protected]>2022-11-22 18:50:43 -0800
commit44af0b45d58d7b6f09ebb9081aa89b8bdc33a630 (patch)
treeeacade4974dd134b4dc4d02490ea742d71bde44e
parent50c697215a8cc22f0e58c88f06f2716c05a26e85 (diff)
mm/migrate_device: return number of migrating pages in args->cpages
migrate_vma->cpages originally contained a count of the number of pages migrating including non-present pages which can be populated directly on the target. Commit 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and migrate_device_coherent_page()") inadvertantly changed this to contain just the number of pages that were unmapped. Usage of migrate_vma->cpages isn't documented, but most drivers use it to see if all the requested addresses can be migrated so restore the original behaviour. Link: https://lkml.kernel.org/r/[email protected] Fixes: 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()") Signed-off-by: Alistair Popple <[email protected]> Reported-by: Ralph Campbell <[email protected]> Reviewed-by: Ralph Campbell <[email protected]> Cc: John Hubbard <[email protected]> Cc: Alex Sierra <[email protected]> Cc: Ben Skeggs <[email protected]> Cc: Felix Kuehling <[email protected]> Cc: Lyude Paul <[email protected]> Cc: Jason Gunthorpe <[email protected]> Cc: Michael Ellerman <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
-rw-r--r--mm/migrate_device.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 6fa682eef7a0..721b2365dbca 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -357,7 +357,8 @@ static bool migrate_vma_check_page(struct page *page, struct page *fault_page)
}
/*
- * Unmaps pages for migration. Returns number of unmapped pages.
+ * Unmaps pages for migration. Returns number of source pfns marked as
+ * migrating.
*/
static unsigned long migrate_device_unmap(unsigned long *src_pfns,
unsigned long npages,
@@ -373,8 +374,11 @@ static unsigned long migrate_device_unmap(unsigned long *src_pfns,
struct page *page = migrate_pfn_to_page(src_pfns[i]);
struct folio *folio;
- if (!page)
+ if (!page) {
+ if (src_pfns[i] & MIGRATE_PFN_MIGRATE)
+ unmapped++;
continue;
+ }
/* ZONE_DEVICE pages are not on LRU */
if (!is_zone_device_page(page)) {