The patch titled
mm/memory-failure.c: fix spinlock vs mutex order
has been removed from the -mm tree. Its filename was
mm-memory-failurec-fix-spinlock-vs-mutex-order.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm/memory-failure.c: fix spinlock vs mutex order
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
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@xxxxxxxxx>
Acked-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 21 ++++++---------------
mm/rmap.c | 5 ++---
2 files changed, 8 insertions(+), 18 deletions(-)
diff -puN mm/memory-failure.c~mm-memory-failurec-fix-spinlock-vs-mutex-order mm/memory-failure.c
--- a/mm/memory-failure.c~mm-memory-failurec-fix-spinlock-vs-mutex-order
+++ a/mm/memory-failure.c
@@ -391,10 +391,11 @@ static void collect_procs_anon(struct pa
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 pa
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 pa
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 pa
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);
}
/*
diff -puN mm/rmap.c~mm-memory-failurec-fix-spinlock-vs-mutex-order mm/rmap.c
--- a/mm/rmap.c~mm-memory-failurec-fix-spinlock-vs-mutex-order
+++ a/mm/rmap.c
@@ -38,9 +38,8 @@
* in arch-dependent flush_dcache_mmap_lock,
* within inode_wb_list_lock in __sync_single_inode)
*
- * (code doesn't rely on that order so it could be switched around)
- * ->tasklist_lock
- * anon_vma->mutex (memory_failure, collect_procs_anon)
+ * anon_vma->mutex,mapping->i_mutex (memory_failure, collect_procs_anon)
+ * ->tasklist_lock
* pte map lock
*/
_
Patches currently in -mm which might be from peterz@xxxxxxxxxxxxx are
linux-next.patch
bdi_min_ratio-never-shrinks-ultimately-preventing-valid-setting-of-min_ratio.patch
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