5 files changed, 26 insertions, 7 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 71a58f67f481..bd939a574b84 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -313,6 +313,19 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
                 } else if (!locked)
                         spin_lock_irq(&zone->lru_lock);
 
+                /*
+                 * migrate_pfn does not necessarily start aligned to a
+                 * pageblock. Ensure that pfn_valid is called when moving
+                 * into a new MAX_ORDER_NR_PAGES range in case of large
+                 * memory holes within the zone
+                 */
+                if ((low_pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) {
+                        if (!pfn_valid(low_pfn)) {
+                                low_pfn += MAX_ORDER_NR_PAGES - 1;
+                                continue;
+                        }
+                }
+
                 if (!pfn_valid_within(low_pfn))
                         continue;
                 nr_scanned++;
diff --git a/mm/filemap.c b/mm/filemap.c
index 97f49ed35bd2..b66275757c28 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1400,15 +1400,12 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
         unsigned long seg = 0;
         size_t count;
         loff_t *ppos = &iocb->ki_pos;
-        struct blk_plug plug;
 
         count = 0;
         retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
         if (retval)
                 return retval;
 
-        blk_start_plug(&plug);
-
         /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
         if (filp->f_flags & O_DIRECT) {
                 loff_t size;
@@ -1424,8 +1421,12 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
                         retval = filemap_write_and_wait_range(mapping, pos,
                                         pos + iov_length(iov, nr_segs) - 1);
                         if (!retval) {
+                                struct blk_plug plug;
+
+                                blk_start_plug(&plug);
                                 retval = mapping->a_ops->direct_IO(READ, iocb,
                                                         iov, pos, nr_segs);
+                                blk_finish_plug(&plug);
                         }
                         if (retval > 0) {
                                 *ppos = pos + retval;
@@ -1481,7 +1482,6 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
                         break;
         }
 out:
-        blk_finish_plug(&plug);
         return retval;
 }
 EXPORT_SYMBOL(generic_file_aio_read);
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index f91b2f687343..a4eb31132229 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -263,7 +263,12 @@ found:
                                                         xip_pfn);
                 if (err == -ENOMEM)
                         return VM_FAULT_OOM;
-                BUG_ON(err);
+                /*
+                 * err == -EBUSY is fine, we've raced against another thread
+                 * that faulted-in the same page
+                 */
+                if (err != -EBUSY)
+                        BUG_ON(err);
                 return VM_FAULT_NOPAGE;
         } else {
                 int err, ret = VM_FAULT_OOM;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 556859fec4ef..6728a7ae6f2d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -776,7 +776,8 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
         /* threshold event is triggered in finer grain than soft limit */
         if (unlikely(mem_cgroup_event_ratelimit(memcg,
                                                 MEM_CGROUP_TARGET_THRESH))) {
-                bool do_softlimit, do_numainfo;
+                bool do_softlimit;
+                bool do_numainfo __maybe_unused;
 
                 do_softlimit = mem_cgroup_event_ratelimit(memcg,
                                                 MEM_CGROUP_TARGET_SOFTLIMIT);
diff --git a/mm/migrate.c b/mm/migrate.c
index 9871a56d82c3..df141f60289e 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -445,7 +445,6 @@ void migrate_page_copy(struct page *newpage, struct page *page)
         ClearPageSwapCache(page);
         ClearPagePrivate(page);
         set_page_private(page, 0);
-        page->mapping = NULL;
 
         /*
          * If any waiters have accumulated on the new page then
@@ -667,6 +666,7 @@ static int move_to_new_page(struct page *newpage, struct page *page,
         } else {
                 if (remap_swapcache)
                         remove_migration_ptes(page, newpage);
+                page->mapping = NULL;
         }
 
         unlock_page(newpage);