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Subject[PATCH v3 3/5] net: qrtr: Migrate node lookup tree to spinlock
Date
Move operations on the qrtr_nodes radix tree under a separate spinlock
and make the qrtr_nodes tree GFP_ATOMIC, to allow operation from atomic
context in a subsequent patch.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

Changes since v2:
- None

net/qrtr/qrtr.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index a6da5fa2a9b5..c2bbfa7ec6e2 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -8,6 +8,7 @@
#include <linux/qrtr.h>
#include <linux/termios.h> /* For TIOCINQ/OUTQ */
#include <linux/numa.h>
+#include <linux/spinlock.h>
#include <linux/wait.h>

#include <net/sock.h>
@@ -98,10 +99,11 @@ static inline struct qrtr_sock *qrtr_sk(struct sock *sk)
static unsigned int qrtr_local_nid = NUMA_NO_NODE;

/* for node ids */
-static RADIX_TREE(qrtr_nodes, GFP_KERNEL);
+static RADIX_TREE(qrtr_nodes, GFP_ATOMIC);
+static DEFINE_SPINLOCK(qrtr_nodes_lock);
/* broadcast list */
static LIST_HEAD(qrtr_all_nodes);
-/* lock for qrtr_nodes, qrtr_all_nodes and node reference */
+/* lock for qrtr_all_nodes and node reference */
static DEFINE_MUTEX(qrtr_node_lock);

/* local port allocation management */
@@ -165,10 +167,13 @@ static void __qrtr_node_release(struct kref *kref)
{
struct radix_tree_iter iter;
struct qrtr_node *node = container_of(kref, struct qrtr_node, ref);
+ unsigned long flags;
void __rcu **slot;

+ spin_lock_irqsave(&qrtr_nodes_lock, flags);
if (node->nid != QRTR_EP_NID_AUTO)
radix_tree_delete(&qrtr_nodes, node->nid);
+ spin_unlock_irqrestore(&qrtr_nodes_lock, flags);

list_del(&node->item);
mutex_unlock(&qrtr_node_lock);
@@ -372,11 +377,12 @@ static int qrtr_node_enqueue(struct qrtr_node *node, struct sk_buff *skb,
static struct qrtr_node *qrtr_node_lookup(unsigned int nid)
{
struct qrtr_node *node;
+ unsigned long flags;

- mutex_lock(&qrtr_node_lock);
+ spin_lock_irqsave(&qrtr_nodes_lock, flags);
node = radix_tree_lookup(&qrtr_nodes, nid);
node = qrtr_node_acquire(node);
- mutex_unlock(&qrtr_node_lock);
+ spin_unlock_irqrestore(&qrtr_nodes_lock, flags);

return node;
}
@@ -388,13 +394,15 @@ static struct qrtr_node *qrtr_node_lookup(unsigned int nid)
*/
static void qrtr_node_assign(struct qrtr_node *node, unsigned int nid)
{
+ unsigned long flags;
+
if (node->nid != QRTR_EP_NID_AUTO || nid == QRTR_EP_NID_AUTO)
return;

- mutex_lock(&qrtr_node_lock);
+ spin_lock_irqsave(&qrtr_nodes_lock, flags);
radix_tree_insert(&qrtr_nodes, nid, node);
node->nid = nid;
- mutex_unlock(&qrtr_node_lock);
+ spin_unlock_irqrestore(&qrtr_nodes_lock, flags);
}

/**
--
2.24.0
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