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-rw-r--r--fs/hugetlbfs/inode.c2
-rw-r--r--include/linux/mempolicy.h2
-rw-r--r--mm/mempolicy.c30
3 files changed, 19 insertions, 15 deletions
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index f6820ecf0a11..a1cb8fd2289b 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -738,7 +738,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
/*
* The policy is initialized here even if we are creating a
* private inode because initialization simply creates an
- * an empty rb tree and calls spin_lock_init(), later when we
+ * an empty rb tree and calls rwlock_init(), later when we
* call mpol_free_shared_policy() it will just return because
* the rb tree will still be empty.
*/
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 3d385c81c153..2696c1f05ed1 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -122,7 +122,7 @@ struct sp_node {
struct shared_policy {
struct rb_root root;
- spinlock_t lock;
+ rwlock_t lock;
};
int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 87a177917cb2..d8caff071a30 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2142,12 +2142,14 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
*
* Remember policies even when nobody has shared memory mapped.
* The policies are kept in Red-Black tree linked from the inode.
- * They are protected by the sp->lock spinlock, which should be held
+ * They are protected by the sp->lock rwlock, which should be held
* for any accesses to the tree.
*/
-/* lookup first element intersecting start-end */
-/* Caller holds sp->lock */
+/*
+ * lookup first element intersecting start-end. Caller holds sp->lock for
+ * reading or for writing
+ */
static struct sp_node *
sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
{
@@ -2178,8 +2180,10 @@ sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
return rb_entry(n, struct sp_node, nd);
}
-/* Insert a new shared policy into the list. */
-/* Caller holds sp->lock */
+/*
+ * Insert a new shared policy into the list. Caller holds sp->lock for
+ * writing.
+ */
static void sp_insert(struct shared_policy *sp, struct sp_node *new)
{
struct rb_node **p = &sp->root.rb_node;
@@ -2211,13 +2215,13 @@ mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
if (!sp->root.rb_node)
return NULL;
- spin_lock(&sp->lock);
+ read_lock(&sp->lock);
sn = sp_lookup(sp, idx, idx+1);
if (sn) {
mpol_get(sn->policy);
pol = sn->policy;
}
- spin_unlock(&sp->lock);
+ read_unlock(&sp->lock);
return pol;
}
@@ -2360,7 +2364,7 @@ static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
int ret = 0;
restart:
- spin_lock(&sp->lock);
+ write_lock(&sp->lock);
n = sp_lookup(sp, start, end);
/* Take care of old policies in the same range. */
while (n && n->start < end) {
@@ -2393,7 +2397,7 @@ restart:
}
if (new)
sp_insert(sp, new);
- spin_unlock(&sp->lock);
+ write_unlock(&sp->lock);
ret = 0;
err_out:
@@ -2405,7 +2409,7 @@ err_out:
return ret;
alloc_new:
- spin_unlock(&sp->lock);
+ write_unlock(&sp->lock);
ret = -ENOMEM;
n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
if (!n_new)
@@ -2431,7 +2435,7 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
int ret;
sp->root = RB_ROOT; /* empty tree == default mempolicy */
- spin_lock_init(&sp->lock);
+ rwlock_init(&sp->lock);
if (mpol) {
struct vm_area_struct pvma;
@@ -2497,14 +2501,14 @@ void mpol_free_shared_policy(struct shared_policy *p)
if (!p->root.rb_node)
return;
- spin_lock(&p->lock);
+ write_lock(&p->lock);
next = rb_first(&p->root);
while (next) {
n = rb_entry(next, struct sp_node, nd);
next = rb_next(&n->nd);
sp_delete(p, n);
}
- spin_unlock(&p->lock);
+ write_unlock(&p->lock);
}
#ifdef CONFIG_NUMA_BALANCING