ath9k: make DFS detector pools SMP safe

This adds locking of the detector's shared pulse and PRI sequence
pools to enable multi-wiphy operation on SMP systems.

Signed-off-by: Zefir Kurtisi <zefir.kurtisi@neratec.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath9k/dfs_pri_detector.c b/drivers/net/wireless/ath/ath9k/dfs_pri_detector.c
index 025e88a64fa460ba0c93c45af47615e1de80d5ba..ecb6334fd20fd79c4b4984c02a51f3e574c6fb67 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/dfs_pri_detector.c
+++ b/drivers/net/wireless/ath/ath9k/dfs_pri_detector.c
@@ -15,6 +15,7 @@
  */
 
 #include <linux/slab.h>
+#include <linux/spinlock.h>
 
 #include "dfs_pattern_detector.h"
 #include "dfs_pri_detector.h"
@@ -94,6 +95,73 @@ static u32 pde_get_multiple(u32 val, u32 fraction, u32 tolerance)
 static u32 singleton_pool_references;
 static LIST_HEAD(pulse_pool);
 static LIST_HEAD(pseq_pool);
+static DEFINE_SPINLOCK(pool_lock);
+
+static void pool_register_ref(void)
+{
+       spin_lock_bh(&pool_lock);
+       singleton_pool_references++;
+       spin_unlock_bh(&pool_lock);
+}
+
+static void pool_deregister_ref(void)
+{
+       spin_lock_bh(&pool_lock);
+       singleton_pool_references--;
+       if (singleton_pool_references == 0) {
+               /* free singleton pools with no references left */
+               struct pri_sequence *ps, *ps0;
+               struct pulse_elem *p, *p0;
+
+               list_for_each_entry_safe(p, p0, &pulse_pool, head) {
+                       list_del(&p->head);
+                       kfree(p);
+               }
+               list_for_each_entry_safe(ps, ps0, &pseq_pool, head) {
+                       list_del(&ps->head);
+                       kfree(ps);
+               }
+       }
+       spin_unlock_bh(&pool_lock);
+}
+
+static void pool_put_pulse_elem(struct pulse_elem *pe)
+{
+       spin_lock_bh(&pool_lock);
+       list_add(&pe->head, &pulse_pool);
+       spin_unlock_bh(&pool_lock);
+}
+
+static void pool_put_pseq_elem(struct pri_sequence *pse)
+{
+       spin_lock_bh(&pool_lock);
+       list_add(&pse->head, &pseq_pool);
+       spin_unlock_bh(&pool_lock);
+}
+
+static struct pri_sequence *pool_get_pseq_elem(void)
+{
+       struct pri_sequence *pse = NULL;
+       spin_lock_bh(&pool_lock);
+       if (!list_empty(&pseq_pool)) {
+               pse = list_first_entry(&pseq_pool, struct pri_sequence, head);
+               list_del(&pse->head);
+       }
+       spin_unlock_bh(&pool_lock);
+       return pse;
+}
+
+static struct pulse_elem *pool_get_pulse_elem(void)
+{
+       struct pulse_elem *pe = NULL;
+       spin_lock_bh(&pool_lock);
+       if (!list_empty(&pulse_pool)) {
+               pe = list_first_entry(&pulse_pool, struct pulse_elem, head);
+               list_del(&pe->head);
+       }
+       spin_unlock_bh(&pool_lock);
+       return pe;
+}
 
 static struct pulse_elem *pulse_queue_get_tail(struct pri_detector *pde)
 {
@@ -110,7 +178,7 @@ static bool pulse_queue_dequeue(struct pri_detector *pde)
                list_del_init(&p->head);
                pde->count--;
                /* give it back to pool */
-               list_add(&p->head, &pulse_pool);
+               pool_put_pulse_elem(p);
        }
        return (pde->count > 0);
 }
@@ -138,11 +206,8 @@ static void pulse_queue_check_window(struct pri_detector *pde)
 
 static bool pulse_queue_enqueue(struct pri_detector *pde, u64 ts)
 {
-       struct pulse_elem *p;
-       if (!list_empty(&pulse_pool)) {
-               p = list_first_entry(&pulse_pool, struct pulse_elem, head);
-               list_del(&p->head);
-       } else {
+       struct pulse_elem *p = pool_get_pulse_elem();
+       if (p == NULL) {
                p = kmalloc(sizeof(*p), GFP_KERNEL);
                if (p == NULL) {
                        pr_err("failed to allocate pulse_elem\n");
@@ -220,12 +285,8 @@ static bool pseq_handler_create_sequences(struct pri_detector *pde,
 
                /* this is a valid one, add it */
                ps.deadline_ts = ps.first_ts + ps.dur;
-
-               if (!list_empty(&pseq_pool)) {
-                       new_ps = list_first_entry(&pseq_pool,
-                                                 struct pri_sequence, head);
-                       list_del(&new_ps->head);
-               } else {
+               new_ps = pool_get_pseq_elem();
+               if (new_ps == NULL) {
                        new_ps = kmalloc(sizeof(*new_ps), GFP_KERNEL);
                        if (new_ps == NULL)
                                return false;
@@ -250,7 +311,7 @@ pseq_handler_add_to_existing_seqs(struct pri_detector *pde, u64 ts)
                /* first ensure that sequence is within window */
                if (ts > ps->deadline_ts) {
                        list_del_init(&ps->head);
-                       list_add(&ps->head, &pseq_pool);
+                       pool_put_pseq_elem(ps);
                        continue;
                }
 
@@ -299,11 +360,11 @@ static void pri_detector_reset(struct pri_detector *pde, u64 ts)
        struct pulse_elem *p, *p0;
        list_for_each_entry_safe(ps, ps0, &pde->sequences, head) {
                list_del_init(&ps->head);
-               list_add(&ps->head, &pseq_pool);
+               pool_put_pseq_elem(ps);
        }
        list_for_each_entry_safe(p, p0, &pde->pulses, head) {
                list_del_init(&p->head);
-               list_add(&p->head, &pulse_pool);
+               pool_put_pulse_elem(p);
        }
        pde->count = 0;
        pde->last_ts = ts;
@@ -312,22 +373,7 @@ static void pri_detector_reset(struct pri_detector *pde, u64 ts)
 static void pri_detector_exit(struct pri_detector *de)
 {
        pri_detector_reset(de, 0);
-
-       singleton_pool_references--;
-       if (singleton_pool_references == 0) {
-               /* free singleton pools with no references left */
-               struct pri_sequence *ps, *ps0;
-               struct pulse_elem *p, *p0;
-
-               list_for_each_entry_safe(p, p0, &pulse_pool, head) {
-                       list_del(&p->head);
-                       kfree(p);
-               }
-               list_for_each_entry_safe(ps, ps0, &pseq_pool, head) {
-                       list_del(&ps->head);
-                       kfree(ps);
-               }
-       }
+       pool_deregister_ref();
        kfree(de);
 }
 
@@ -385,6 +431,6 @@ pri_detector_init(const struct radar_detector_specs *rs)
        de->max_count = rs->ppb * 2;
        de->rs = rs;
 
-       singleton_pool_references++;
+       pool_register_ref();
        return de;
 }