[RESEND PATCH 2/4 v3] mm: fix possible incorrect return value of migrate_pages() syscall
From: Joonsoo Kim <hidden>
Date: 2012-07-27 17:57:04
Also in:
lkml
Subsystem:
memory management, memory management - memory policy and migration, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
do_migrate_pages() can return the number of pages not migrated. Because migrate_pages() syscall return this value directly, migrate_pages() syscall may return the number of pages not migrated. In fail case in migrate_pages() syscall, we should return error value. So change err to -EBUSY Additionally, Correct comment above do_migrate_pages() Signed-off-by: Joonsoo Kim <redacted> Cc: Sasha Levin <redacted> Cc: Christoph Lameter <redacted> Acked-by: Michal Nazarewicz <redacted>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 1d771e4..0732729 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c@@ -948,7 +948,7 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest, * Move pages between the two nodesets so as to preserve the physical * layout as much as possible. * - * Returns the number of page that could not be moved. + * Returns error or the number of pages not migrated. */ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, const nodemask_t *to, int flags)
@@ -1382,6 +1382,8 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode, err = do_migrate_pages(mm, old, new, capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE); + if (err > 0) + err = -EBUSY; mmput(mm); out:
--
1.7.9.5
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