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authorPeter Zijlstra <peterz@infradead.org>2011-06-27 16:18:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-06-27 18:00:13 -0700
commit9b679320a5fbf46454011e5c62e0b8991b0956d1 (patch)
tree49ea7be5e8bb669ef99533a18c73555e2882efc5 /mm/memory-failure.c
parentaa2c96d6f329e66cc59352b0f12e8f04e6a9593b (diff)
downloadlinux-9b679320a5fbf46454011e5c62e0b8991b0956d1.tar.gz
mm/memory-failure.c: fix spinlock vs mutex order
We cannot take a mutex while holding a spinlock, so flip the order and fix the locking documentation. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory-failure.c')
-rw-r--r--mm/memory-failure.c21
1 files changed, 6 insertions, 15 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index eac0ba56149..740c4f52059 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -391,10 +391,11 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
struct task_struct *tsk;
struct anon_vma *av;
- read_lock(&tasklist_lock);
av = page_lock_anon_vma(page);
if (av == NULL) /* Not actually mapped anymore */
- goto out;
+ return;
+
+ read_lock(&tasklist_lock);
for_each_process (tsk) {
struct anon_vma_chain *vmac;
@@ -408,9 +409,8 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
add_to_kill(tsk, page, vma, to_kill, tkc);
}
}
- page_unlock_anon_vma(av);
-out:
read_unlock(&tasklist_lock);
+ page_unlock_anon_vma(av);
}
/*
@@ -424,17 +424,8 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
struct prio_tree_iter iter;
struct address_space *mapping = page->mapping;
- /*
- * A note on the locking order between the two locks.
- * We don't rely on this particular order.
- * If you have some other code that needs a different order
- * feel free to switch them around. Or add a reverse link
- * from mm_struct to task_struct, then this could be all
- * done without taking tasklist_lock and looping over all tasks.
- */
-
- read_lock(&tasklist_lock);
mutex_lock(&mapping->i_mmap_mutex);
+ read_lock(&tasklist_lock);
for_each_process(tsk) {
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -454,8 +445,8 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
add_to_kill(tsk, page, vma, to_kill, tkc);
}
}
- mutex_unlock(&mapping->i_mmap_mutex);
read_unlock(&tasklist_lock);
+ mutex_unlock(&mapping->i_mmap_mutex);
}
/*