FAILED: patch "[PATCH] vmw_balloon: indicate success when effectively deflating" failed to apply to 6.17-stable tree
The patch below does not apply to the 6.17-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.17.y git checkout FETCH_HEAD git cherry-pick -x 4ba5a8a7faa647ada8eae61a36517cf369f5bbe4 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025102655-unequal-disown-9615@gregkh' --subject-prefix 'PATCH 6.17.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4ba5a8a7faa647ada8eae61a36517cf369f5bbe4 Mon Sep 17 00:00:00 2001 From: David Hildenbrand david@redhat.com Date: Tue, 14 Oct 2025 14:44:55 +0200 Subject: [PATCH] vmw_balloon: indicate success when effectively deflating during migration
When migrating a balloon page, we first deflate the old page to then inflate the new page.
However, if inflating the new page succeeded, we effectively deflated the old page, reducing the balloon size.
In that case, the migration actually worked: similar to migrating+ immediately deflating the new page. The old page will be freed back to the buddy.
Right now, the core will leave the page be marked as isolated (as we returned an error). When later trying to putback that page, we will run into the WARN_ON_ONCE() in balloon_page_putback().
That handling was changed in commit 3544c4faccb8 ("mm/balloon_compaction: stop using __ClearPageMovable()"); before that change, we would have tolerated that way of handling it.
To fix it, let's just return 0 in that case, making the core effectively just clear the "isolated" flag + freeing it back to the buddy as if the migration succeeded. Note that the new page will also get freed when the core puts the last reference.
Note that this also makes it all be more consistent: we will no longer unisolate the page in the balloon driver while keeping it marked as being isolated in migration core.
This was found by code inspection.
Link: https://lkml.kernel.org/r/20251014124455.478345-1-david@redhat.com Fixes: 3544c4faccb8 ("mm/balloon_compaction: stop using __ClearPageMovable()") Signed-off-by: David Hildenbrand david@redhat.com Cc: Jerrin Shaji George jerrin.shaji-george@broadcom.com Cc: Broadcom internal kernel review list bcm-kernel-feedback-list@broadcom.com Cc: Arnd Bergmann arnd@arndb.de Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index 6df51ee8db62..cc1d18b3df5c 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -1737,7 +1737,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, { unsigned long status, flags; struct vmballoon *b; - int ret; + int ret = 0;
b = container_of(b_dev_info, struct vmballoon, b_dev_info);
@@ -1796,17 +1796,15 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, * A failure happened. While we can deflate the page we just * inflated, this deflation can also encounter an error. Instead * we will decrease the size of the balloon to reflect the - * change and report failure. + * change. */ atomic64_dec(&b->size); - ret = -EBUSY; } else { /* * Success. Take a reference for the page, and we will add it to * the list after acquiring the lock. */ get_page(newpage); - ret = 0; }
/* Update the balloon list under the @pages_lock */ @@ -1817,7 +1815,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, * If we succeed just insert it to the list and update the statistics * under the lock. */ - if (!ret) { + if (status == VMW_BALLOON_SUCCESS) { balloon_page_insert(&b->b_dev_info, newpage); __count_vm_event(BALLOON_MIGRATE); }
From: David Hildenbrand david@redhat.com
[ Upstream commit 95c2908f1a4fd608b1cdbb5acef3572e5d769e1c ]
migrate_folio_unmap() is the only user of MIGRATEPAGE_UNMAP. We want to remove MIGRATEPAGE_* completely.
It's rather weird to have a generic MIGRATEPAGE_UNMAP, documented to be returned from address-space callbacks, when it's only used for an internal helper.
Let's start by having only a single "success" return value for migrate_folio_unmap() -- 0 -- by moving the "folio was already freed" check into the single caller.
There is a remaining comment for PG_isolated, which we renamed to PG_movable_ops_isolated recently and forgot to update.
While we might still run into that case with zsmalloc, it's something we want to get rid of soon. So let's just focus that optimization on real folios only for now by excluding movable_ops pages. Note that concurrent freeing can happen at any time and this "already freed" check is not relevant for correctness.
[david@redhat.com: no need to pass "reason" to migrate_folio_unmap(), per Lance] Link: https://lkml.kernel.org/r/3bb725f8-28d7-4aa2-b75f-af40d5cab280@redhat.com Link: https://lkml.kernel.org/r/20250811143949.1117439-2-david@redhat.com Signed-off-by: David Hildenbrand david@redhat.com Reviewed-by: Zi Yan ziy@nvidia.com Reviewed-by: Lance Yang lance.yang@linux.dev Cc: Alistair Popple apopple@nvidia.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Arnd Bergmann arnd@arndb.de Cc: Benjamin LaHaise bcrl@kvack.org Cc: Byungchul Park byungchul@sk.com Cc: Chris Mason clm@fb.com Cc: Christian Brauner brauner@kernel.org Cc: Christophe Leroy christophe.leroy@csgroup.eu Cc: Dave Kleikamp shaggy@kernel.org Cc: David Sterba dsterba@suse.com Cc: Eugenio Pé rez eperezma@redhat.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Gregory Price gourry@gourry.net Cc: "Huang, Ying" ying.huang@linux.alibaba.com Cc: Jan Kara jack@suse.cz Cc: Jason Wang jasowang@redhat.com Cc: Jerrin Shaji George jerrin.shaji-george@broadcom.com Cc: Josef Bacik josef@toxicpanda.com Cc: Joshua Hahn joshua.hahnjy@gmail.com Cc: Madhavan Srinivasan maddy@linux.ibm.com Cc: Mathew Brost matthew.brost@intel.com Cc: Michael Ellerman mpe@ellerman.id.au Cc: "Michael S. Tsirkin" mst@redhat.com Cc: Minchan Kim minchan@kernel.org Cc: Muchun Song muchun.song@linux.dev Cc: Nicholas Piggin npiggin@gmail.com Cc: Oscar Salvador osalvador@suse.de Cc: Rakie Kim rakie.kim@sk.com Cc: Sergey Senozhatsky senozhatsky@chromium.org Cc: Xuan Zhuo xuanzhuo@linux.alibaba.com Cc: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Stable-dep-of: 4ba5a8a7faa6 ("vmw_balloon: indicate success when effectively deflating during migration") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/migrate.h | 1 - mm/migrate.c | 45 ++++++++++++++++++++--------------------- 2 files changed, 22 insertions(+), 24 deletions(-)
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 9009e27b5f44c..302f3e95faeaa 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -18,7 +18,6 @@ struct migration_target_control; * - zero on page migration success; */ #define MIGRATEPAGE_SUCCESS 0 -#define MIGRATEPAGE_UNMAP 1
/** * struct movable_operations - Driver page migration diff --git a/mm/migrate.c b/mm/migrate.c index 4ff6eea0ef7ed..e38c933d0c376 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1188,7 +1188,7 @@ static void migrate_folio_done(struct folio *src, static int migrate_folio_unmap(new_folio_t get_new_folio, free_folio_t put_new_folio, unsigned long private, struct folio *src, struct folio **dstp, enum migrate_mode mode, - enum migrate_reason reason, struct list_head *ret) + struct list_head *ret) { struct folio *dst; int rc = -EAGAIN; @@ -1197,16 +1197,6 @@ static int migrate_folio_unmap(new_folio_t get_new_folio, bool locked = false; bool dst_locked = false;
- if (folio_ref_count(src) == 1) { - /* Folio was freed from under us. So we are done. */ - folio_clear_active(src); - folio_clear_unevictable(src); - /* free_pages_prepare() will clear PG_isolated. */ - list_del(&src->lru); - migrate_folio_done(src, reason); - return MIGRATEPAGE_SUCCESS; - } - dst = get_new_folio(src, private); if (!dst) return -ENOMEM; @@ -1296,7 +1286,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
if (unlikely(page_has_movable_ops(&src->page))) { __migrate_folio_record(dst, old_page_state, anon_vma); - return MIGRATEPAGE_UNMAP; + return 0; }
/* @@ -1326,7 +1316,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
if (!folio_mapped(src)) { __migrate_folio_record(dst, old_page_state, anon_vma); - return MIGRATEPAGE_UNMAP; + return 0; }
out: @@ -1869,14 +1859,27 @@ static int migrate_pages_batch(struct list_head *from, continue; }
+ /* + * If we are holding the last folio reference, the folio + * was freed from under us, so just drop our reference. + */ + if (likely(!page_has_movable_ops(&folio->page)) && + folio_ref_count(folio) == 1) { + folio_clear_active(folio); + folio_clear_unevictable(folio); + list_del(&folio->lru); + migrate_folio_done(folio, reason); + stats->nr_succeeded += nr_pages; + stats->nr_thp_succeeded += is_thp; + continue; + } + rc = migrate_folio_unmap(get_new_folio, put_new_folio, - private, folio, &dst, mode, reason, - ret_folios); + private, folio, &dst, mode, ret_folios); /* * The rules are: - * Success: folio will be freed - * Unmap: folio will be put on unmap_folios list, - * dst folio put on dst_folios list + * 0: folio will be put on unmap_folios list, + * dst folio put on dst_folios list * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list * Other errno: put on ret_folios list @@ -1926,11 +1929,7 @@ static int migrate_pages_batch(struct list_head *from, thp_retry += is_thp; nr_retry_pages += nr_pages; break; - case MIGRATEPAGE_SUCCESS: - stats->nr_succeeded += nr_pages; - stats->nr_thp_succeeded += is_thp; - break; - case MIGRATEPAGE_UNMAP: + case 0: list_move_tail(&folio->lru, &unmap_folios); list_add_tail(&dst->lru, &dst_folios); break;
From: David Hildenbrand david@redhat.com
[ Upstream commit fb49a4425cfa163faccd91f913773d3401d3a7d4 ]
At this point MIGRATEPAGE_SUCCESS is misnamed for all folio users, and now that we remove MIGRATEPAGE_UNMAP, it's really the only "success" return value that the code uses and expects.
Let's just get rid of MIGRATEPAGE_SUCCESS completely and just use "0" for success.
Link: https://lkml.kernel.org/r/20250811143949.1117439-3-david@redhat.com Signed-off-by: David Hildenbrand david@redhat.com Reviewed-by: Zi Yan ziy@nvidia.com [mm] Acked-by: Dave Kleikamp dave.kleikamp@oracle.com [jfs] Acked-by: David Sterba dsterba@suse.com [btrfs] Acked-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Reviewed-by: Byungchul Park byungchul@sk.com Cc: Alistair Popple apopple@nvidia.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Arnd Bergmann arnd@arndb.de Cc: Benjamin LaHaise bcrl@kvack.org Cc: Chris Mason clm@fb.com Cc: Christian Brauner brauner@kernel.org Cc: Christophe Leroy christophe.leroy@csgroup.eu Cc: Dave Kleikamp shaggy@kernel.org Cc: Eugenio Pé rez eperezma@redhat.com Cc: Gregory Price gourry@gourry.net Cc: "Huang, Ying" ying.huang@linux.alibaba.com Cc: Jan Kara jack@suse.cz Cc: Jason Wang jasowang@redhat.com Cc: Jerrin Shaji George jerrin.shaji-george@broadcom.com Cc: Josef Bacik josef@toxicpanda.com Cc: Joshua Hahn joshua.hahnjy@gmail.com Cc: Madhavan Srinivasan maddy@linux.ibm.com Cc: Mathew Brost matthew.brost@intel.com Cc: Michael Ellerman mpe@ellerman.id.au Cc: "Michael S. Tsirkin" mst@redhat.com Cc: Minchan Kim minchan@kernel.org Cc: Muchun Song muchun.song@linux.dev Cc: Nicholas Piggin npiggin@gmail.com Cc: Oscar Salvador osalvador@suse.de Cc: Rakie Kim rakie.kim@sk.com Cc: Sergey Senozhatsky senozhatsky@chromium.org Cc: Xuan Zhuo xuanzhuo@linux.alibaba.com Cc: Lance Yang lance.yang@linux.dev Signed-off-by: Andrew Morton akpm@linux-foundation.org Stable-dep-of: 4ba5a8a7faa6 ("vmw_balloon: indicate success when effectively deflating during migration") Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/platforms/pseries/cmm.c | 2 +- drivers/misc/vmw_balloon.c | 4 +-- drivers/virtio/virtio_balloon.c | 2 +- fs/aio.c | 2 +- fs/btrfs/inode.c | 4 +-- fs/hugetlbfs/inode.c | 4 +-- fs/jfs/jfs_metapage.c | 8 +++--- include/linux/migrate.h | 10 +------ mm/migrate.c | 40 +++++++++++++--------------- mm/migrate_device.c | 2 +- mm/zsmalloc.c | 4 +-- 11 files changed, 36 insertions(+), 46 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c index 5e0a718d1be7b..0823fa2da1516 100644 --- a/arch/powerpc/platforms/pseries/cmm.c +++ b/arch/powerpc/platforms/pseries/cmm.c @@ -545,7 +545,7 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info, /* balloon page list reference */ put_page(page);
- return MIGRATEPAGE_SUCCESS; + return 0; }
static void cmm_balloon_compaction_init(void) diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index 6653fc53c951c..6df51ee8db621 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -1806,7 +1806,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, * the list after acquiring the lock. */ get_page(newpage); - ret = MIGRATEPAGE_SUCCESS; + ret = 0; }
/* Update the balloon list under the @pages_lock */ @@ -1817,7 +1817,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, * If we succeed just insert it to the list and update the statistics * under the lock. */ - if (ret == MIGRATEPAGE_SUCCESS) { + if (!ret) { balloon_page_insert(&b->b_dev_info, newpage); __count_vm_event(BALLOON_MIGRATE); } diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index e299e18346a30..eae65136cdfb5 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -875,7 +875,7 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, balloon_page_finalize(page); put_page(page); /* balloon reference */
- return MIGRATEPAGE_SUCCESS; + return 0; } #endif /* CONFIG_BALLOON_COMPACTION */
diff --git a/fs/aio.c b/fs/aio.c index 7fc7b6221312c..059e03cfa088c 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -445,7 +445,7 @@ static int aio_migrate_folio(struct address_space *mapping, struct folio *dst, folio_get(dst);
rc = folio_migrate_mapping(mapping, dst, src, 1); - if (rc != MIGRATEPAGE_SUCCESS) { + if (rc) { folio_put(dst); goto out_unlock; } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index cd8a09e3d1dc0..4031cbdea0740 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7430,7 +7430,7 @@ static int btrfs_migrate_folio(struct address_space *mapping, { int ret = filemap_migrate_folio(mapping, dst, src, mode);
- if (ret != MIGRATEPAGE_SUCCESS) + if (ret) return ret;
if (folio_test_ordered(src)) { @@ -7438,7 +7438,7 @@ static int btrfs_migrate_folio(struct address_space *mapping, folio_set_ordered(dst); }
- return MIGRATEPAGE_SUCCESS; + return 0; } #else #define btrfs_migrate_folio NULL diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index be4be99304bc0..5517d40266ddf 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -1054,7 +1054,7 @@ static int hugetlbfs_migrate_folio(struct address_space *mapping, int rc;
rc = migrate_huge_page_move_mapping(mapping, dst, src); - if (rc != MIGRATEPAGE_SUCCESS) + if (rc) return rc;
if (hugetlb_folio_subpool(src)) { @@ -1065,7 +1065,7 @@ static int hugetlbfs_migrate_folio(struct address_space *mapping,
folio_migrate_flags(dst, src);
- return MIGRATEPAGE_SUCCESS; + return 0; } #else #define hugetlbfs_migrate_folio NULL diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c index b98cf3bb6c1fe..871cf4fb36366 100644 --- a/fs/jfs/jfs_metapage.c +++ b/fs/jfs/jfs_metapage.c @@ -169,7 +169,7 @@ static int __metapage_migrate_folio(struct address_space *mapping, }
rc = filemap_migrate_folio(mapping, dst, src, mode); - if (rc != MIGRATEPAGE_SUCCESS) + if (rc) return rc;
for (i = 0; i < MPS_PER_PAGE; i++) { @@ -199,7 +199,7 @@ static int __metapage_migrate_folio(struct address_space *mapping, } }
- return MIGRATEPAGE_SUCCESS; + return 0; } #endif /* CONFIG_MIGRATION */
@@ -242,7 +242,7 @@ static int __metapage_migrate_folio(struct address_space *mapping, return -EAGAIN;
rc = filemap_migrate_folio(mapping, dst, src, mode); - if (rc != MIGRATEPAGE_SUCCESS) + if (rc) return rc;
if (unlikely(insert_metapage(dst, mp))) @@ -253,7 +253,7 @@ static int __metapage_migrate_folio(struct address_space *mapping, mp->folio = dst; remove_metapage(src, mp);
- return MIGRATEPAGE_SUCCESS; + return 0; } #endif /* CONFIG_MIGRATION */
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 302f3e95faeaa..1f0ac122c3bfc 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -12,13 +12,6 @@ typedef void free_folio_t(struct folio *folio, unsigned long private);
struct migration_target_control;
-/* - * Return values from addresss_space_operations.migratepage(): - * - negative errno on page migration failure; - * - zero on page migration success; - */ -#define MIGRATEPAGE_SUCCESS 0 - /** * struct movable_operations - Driver page migration * @isolate_page: @@ -34,8 +27,7 @@ struct migration_target_control; * @src page. The driver should copy the contents of the * @src page to the @dst page and set up the fields of @dst page. * Both pages are locked. - * If page migration is successful, the driver should - * return MIGRATEPAGE_SUCCESS. + * If page migration is successful, the driver should return 0. * If the driver cannot migrate the page at the moment, it can return * -EAGAIN. The VM interprets this as a temporary migration failure and * will retry it later. Any other error value is a permanent migration diff --git a/mm/migrate.c b/mm/migrate.c index e38c933d0c376..bf6b1753a1976 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -231,18 +231,17 @@ static void putback_movable_ops_page(struct page *page) * src and dst are also released by migration core. These pages will not be * folios in the future, so that must be reworked. * - * Returns MIGRATEPAGE_SUCCESS on success, otherwise a negative error - * code. + * Returns 0 on success, otherwise a negative error code. */ static int migrate_movable_ops_page(struct page *dst, struct page *src, enum migrate_mode mode) { - int rc = MIGRATEPAGE_SUCCESS; + int rc;
VM_WARN_ON_ONCE_PAGE(!page_has_movable_ops(src), src); VM_WARN_ON_ONCE_PAGE(!PageMovableOpsIsolated(src), src); rc = page_movable_ops(src)->migrate_page(dst, src, mode); - if (rc == MIGRATEPAGE_SUCCESS) + if (!rc) ClearPageMovableOpsIsolated(src); return rc; } @@ -586,7 +585,7 @@ static int __folio_migrate_mapping(struct address_space *mapping, if (folio_test_swapbacked(folio)) __folio_set_swapbacked(newfolio);
- return MIGRATEPAGE_SUCCESS; + return 0; }
oldzone = folio_zone(folio); @@ -687,7 +686,7 @@ static int __folio_migrate_mapping(struct address_space *mapping, } local_irq_enable();
- return MIGRATEPAGE_SUCCESS; + return 0; }
int folio_migrate_mapping(struct address_space *mapping, @@ -736,7 +735,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
xas_unlock_irq(&xas);
- return MIGRATEPAGE_SUCCESS; + return 0; }
/* @@ -852,14 +851,14 @@ static int __migrate_folio(struct address_space *mapping, struct folio *dst, return rc;
rc = __folio_migrate_mapping(mapping, dst, src, expected_count); - if (rc != MIGRATEPAGE_SUCCESS) + if (rc) return rc;
if (src_private) folio_attach_private(dst, folio_detach_private(src));
folio_migrate_flags(dst, src); - return MIGRATEPAGE_SUCCESS; + return 0; }
/** @@ -966,7 +965,7 @@ static int __buffer_migrate_folio(struct address_space *mapping, }
rc = filemap_migrate_folio(mapping, dst, src, mode); - if (rc != MIGRATEPAGE_SUCCESS) + if (rc) goto unlock_buffers;
bh = head; @@ -1070,7 +1069,7 @@ static int fallback_migrate_folio(struct address_space *mapping, * * Return value: * < 0 - error code - * MIGRATEPAGE_SUCCESS - success + * 0 - success */ static int move_to_new_folio(struct folio *dst, struct folio *src, enum migrate_mode mode) @@ -1098,7 +1097,7 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, else rc = fallback_migrate_folio(mapping, dst, src, mode);
- if (rc == MIGRATEPAGE_SUCCESS) { + if (!rc) { /* * For pagecache folios, src->mapping must be cleared before src * is freed. Anonymous folios must stay anonymous until freed. @@ -1448,7 +1447,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio, if (folio_ref_count(src) == 1) { /* page was freed from under us. So we are done. */ folio_putback_hugetlb(src); - return MIGRATEPAGE_SUCCESS; + return 0; }
dst = get_new_folio(src, private); @@ -1511,8 +1510,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio, rc = move_to_new_folio(dst, src, mode);
if (page_was_mapped) - remove_migration_ptes(src, - rc == MIGRATEPAGE_SUCCESS ? dst : src, 0); + remove_migration_ptes(src, !rc ? dst : src, 0);
unlock_put_anon: folio_unlock(dst); @@ -1521,7 +1519,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio, if (anon_vma) put_anon_vma(anon_vma);
- if (rc == MIGRATEPAGE_SUCCESS) { + if (!rc) { move_hugetlb_state(src, dst, reason); put_new_folio = NULL; } @@ -1529,7 +1527,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio, out_unlock: folio_unlock(src); out: - if (rc == MIGRATEPAGE_SUCCESS) + if (!rc) folio_putback_hugetlb(src); else if (rc != -EAGAIN) list_move_tail(&src->lru, ret); @@ -1639,7 +1637,7 @@ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio, reason, ret_folios); /* * The rules are: - * Success: hugetlb folio will be put back + * 0: hugetlb folio will be put back * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list * Other errno: put on ret_folios list @@ -1656,7 +1654,7 @@ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio, retry++; nr_retry_pages += nr_pages; break; - case MIGRATEPAGE_SUCCESS: + case 0: stats->nr_succeeded += nr_pages; break; default: @@ -1710,7 +1708,7 @@ static void migrate_folios_move(struct list_head *src_folios, reason, ret_folios); /* * The rules are: - * Success: folio will be freed + * 0: folio will be freed * -EAGAIN: stay on the unmap_folios list * Other errno: put on ret_folios list */ @@ -1720,7 +1718,7 @@ static void migrate_folios_move(struct list_head *src_folios, *thp_retry += is_thp; *nr_retry_pages += nr_pages; break; - case MIGRATEPAGE_SUCCESS: + case 0: stats->nr_succeeded += nr_pages; stats->nr_thp_succeeded += is_thp; break; diff --git a/mm/migrate_device.c b/mm/migrate_device.c index e05e14d6eacdb..abd9f6850db65 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -778,7 +778,7 @@ static void __migrate_device_pages(unsigned long *src_pfns, if (migrate && migrate->fault_page == page) extra_cnt = 1; r = folio_migrate_mapping(mapping, newfolio, folio, extra_cnt); - if (r != MIGRATEPAGE_SUCCESS) + if (r) src_pfns[i] &= ~MIGRATE_PFN_MIGRATE; else folio_migrate_flags(newfolio, folio); diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 805a10b41266a..153783d49d346 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1746,7 +1746,7 @@ static int zs_page_migrate(struct page *newpage, struct page *page, * instead. */ if (!zpdesc->zspage) - return MIGRATEPAGE_SUCCESS; + return 0;
/* The page is locked, so this pointer must remain valid */ zspage = get_zspage(zpdesc); @@ -1813,7 +1813,7 @@ static int zs_page_migrate(struct page *newpage, struct page *page, reset_zpdesc(zpdesc); zpdesc_put(zpdesc);
- return MIGRATEPAGE_SUCCESS; + return 0; }
static void zs_page_putback(struct page *page)
From: David Hildenbrand david@redhat.com
[ Upstream commit 4ba5a8a7faa647ada8eae61a36517cf369f5bbe4 ]
When migrating a balloon page, we first deflate the old page to then inflate the new page.
However, if inflating the new page succeeded, we effectively deflated the old page, reducing the balloon size.
In that case, the migration actually worked: similar to migrating+ immediately deflating the new page. The old page will be freed back to the buddy.
Right now, the core will leave the page be marked as isolated (as we returned an error). When later trying to putback that page, we will run into the WARN_ON_ONCE() in balloon_page_putback().
That handling was changed in commit 3544c4faccb8 ("mm/balloon_compaction: stop using __ClearPageMovable()"); before that change, we would have tolerated that way of handling it.
To fix it, let's just return 0 in that case, making the core effectively just clear the "isolated" flag + freeing it back to the buddy as if the migration succeeded. Note that the new page will also get freed when the core puts the last reference.
Note that this also makes it all be more consistent: we will no longer unisolate the page in the balloon driver while keeping it marked as being isolated in migration core.
This was found by code inspection.
Link: https://lkml.kernel.org/r/20251014124455.478345-1-david@redhat.com Fixes: 3544c4faccb8 ("mm/balloon_compaction: stop using __ClearPageMovable()") Signed-off-by: David Hildenbrand david@redhat.com Cc: Jerrin Shaji George jerrin.shaji-george@broadcom.com Cc: Broadcom internal kernel review list bcm-kernel-feedback-list@broadcom.com Cc: Arnd Bergmann arnd@arndb.de Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/misc/vmw_balloon.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index 6df51ee8db621..cc1d18b3df5ca 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -1737,7 +1737,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, { unsigned long status, flags; struct vmballoon *b; - int ret; + int ret = 0;
b = container_of(b_dev_info, struct vmballoon, b_dev_info);
@@ -1796,17 +1796,15 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, * A failure happened. While we can deflate the page we just * inflated, this deflation can also encounter an error. Instead * we will decrease the size of the balloon to reflect the - * change and report failure. + * change. */ atomic64_dec(&b->size); - ret = -EBUSY; } else { /* * Success. Take a reference for the page, and we will add it to * the list after acquiring the lock. */ get_page(newpage); - ret = 0; }
/* Update the balloon list under the @pages_lock */ @@ -1817,7 +1815,7 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, * If we succeed just insert it to the list and update the statistics * under the lock. */ - if (!ret) { + if (status == VMW_BALLOON_SUCCESS) { balloon_page_insert(&b->b_dev_info, newpage); __count_vm_event(BALLOON_MIGRATE); }
linux-stable-mirror@lists.linaro.org
-
gregkh＠linuxfoundation.org -
Sasha Levin