vm_pageout_flush() might cache the pages that finished write to the

backing storage. Such pages might be then reused, racing with the
assert in vm_object_page_collect_flush() that verified that dirty
pages from the run (most likely, pages with VM_PAGER_AGAIN status) are
write-protected still. In fact, the page indexes for the pages that
were removed from the object page list should be ignored by
vm_object_page_clean().

Return the length of successfully written run from vm_pageout_flush(),
that is, the count of pages between requested page and first page
after requested with status VM_PAGER_AGAIN. Supply the requested page
index in the array to vm_pageout_flush(). Use the returned run length
to forward the index of next page to clean in vm_object_page_clean().

Reported by:	avg
Reviewed by:	alc
MFC after:	1 week

1 files changed, 1 insertions, 1 deletions

diff --git a/sys/vm/vm_pageout.h b/sys/vm/vm_pageout.h
index 4857c3e..53e051a 100644
--- a/sys/vm/vm_pageout.h
+++ b/sys/vm/vm_pageout.h
@@ -102,7 +102,7 @@ extern void vm_waitpfault(void);
 
 #ifdef _KERNEL
 boolean_t vm_pageout_fallback_object_lock(vm_page_t, vm_page_t *);
-int vm_pageout_flush(vm_page_t *, int, int);
+int vm_pageout_flush(vm_page_t *, int, int, int, int *);
 void vm_pageout_oom(int shortage);
 boolean_t vm_pageout_page_lock(vm_page_t, vm_page_t *);
 void vm_contig_grow_cache(int, vm_paddr_t, vm_paddr_t);