aboutsummaryrefslogtreecommitdiffstats
path: root/security/keys/gc.c
diff options
context:
space:
mode:
Diffstat (limited to 'security/keys/gc.c')
-rw-r--r--security/keys/gc.c78
1 files changed, 51 insertions, 27 deletions
diff --git a/security/keys/gc.c b/security/keys/gc.c
index 1e616aef55f..485fc6233c3 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -26,8 +26,10 @@ static void key_garbage_collector(struct work_struct *);
static DEFINE_TIMER(key_gc_timer, key_gc_timer_func, 0, 0);
static DECLARE_WORK(key_gc_work, key_garbage_collector);
static key_serial_t key_gc_cursor; /* the last key the gc considered */
+static bool key_gc_again;
static unsigned long key_gc_executing;
static time_t key_gc_next_run = LONG_MAX;
+static time_t key_gc_new_timer;
/*
* Schedule a garbage collection run
@@ -40,9 +42,7 @@ void key_schedule_gc(time_t gc_at)
kenter("%ld", gc_at - now);
- gc_at += key_gc_delay;
-
- if (now >= gc_at) {
+ if (gc_at <= now) {
schedule_work(&key_gc_work);
} else if (gc_at < key_gc_next_run) {
expires = jiffies + (gc_at - now) * HZ;
@@ -112,16 +112,18 @@ static void key_garbage_collector(struct work_struct *work)
struct rb_node *rb;
key_serial_t cursor;
struct key *key, *xkey;
- time_t new_timer = LONG_MAX, limit;
+ time_t new_timer = LONG_MAX, limit, now;
- kenter("");
+ now = current_kernel_time().tv_sec;
+ kenter("[%x,%ld]", key_gc_cursor, key_gc_new_timer - now);
if (test_and_set_bit(0, &key_gc_executing)) {
- key_schedule_gc(current_kernel_time().tv_sec);
+ key_schedule_gc(current_kernel_time().tv_sec + 1);
+ kleave(" [busy; deferring]");
return;
}
- limit = current_kernel_time().tv_sec;
+ limit = now;
if (limit > key_gc_delay)
limit -= key_gc_delay;
else
@@ -129,12 +131,19 @@ static void key_garbage_collector(struct work_struct *work)
spin_lock(&key_serial_lock);
- if (RB_EMPTY_ROOT(&key_serial_tree))
- goto reached_the_end;
+ if (unlikely(RB_EMPTY_ROOT(&key_serial_tree))) {
+ spin_unlock(&key_serial_lock);
+ clear_bit(0, &key_gc_executing);
+ return;
+ }
cursor = key_gc_cursor;
if (cursor < 0)
cursor = 0;
+ if (cursor > 0)
+ new_timer = key_gc_new_timer;
+ else
+ key_gc_again = false;
/* find the first key above the cursor */
key = NULL;
@@ -160,35 +169,50 @@ static void key_garbage_collector(struct work_struct *work)
/* trawl through the keys looking for keyrings */
for (;;) {
- if (key->expiry > 0 && key->expiry < new_timer)
+ if (key->expiry > now && key->expiry < new_timer) {
+ kdebug("will expire %x in %ld",
+ key_serial(key), key->expiry - now);
new_timer = key->expiry;
+ }
if (key->type == &key_type_keyring &&
- key_gc_keyring(key, limit)) {
- /* the gc ate our lock */
- schedule_work(&key_gc_work);
- goto no_unlock;
- }
+ key_gc_keyring(key, limit))
+ /* the gc had to release our lock so that the keyring
+ * could be modified, so we have to get it again */
+ goto gc_released_our_lock;
rb = rb_next(&key->serial_node);
- if (!rb) {
- key_gc_cursor = 0;
- break;
- }
+ if (!rb)
+ goto reached_the_end;
key = rb_entry(rb, struct key, serial_node);
}
-out:
- spin_unlock(&key_serial_lock);
-no_unlock:
+gc_released_our_lock:
+ kdebug("gc_released_our_lock");
+ key_gc_new_timer = new_timer;
+ key_gc_again = true;
clear_bit(0, &key_gc_executing);
- if (new_timer < LONG_MAX)
- key_schedule_gc(new_timer);
-
- kleave("");
+ schedule_work(&key_gc_work);
+ kleave(" [continue]");
return;
+ /* when we reach the end of the run, we set the timer for the next one */
reached_the_end:
+ kdebug("reached_the_end");
+ spin_unlock(&key_serial_lock);
+ key_gc_new_timer = new_timer;
key_gc_cursor = 0;
- goto out;
+ clear_bit(0, &key_gc_executing);
+
+ if (key_gc_again) {
+ /* there may have been a key that expired whilst we were
+ * scanning, so if we discarded any links we should do another
+ * scan */
+ new_timer = now + 1;
+ key_schedule_gc(new_timer);
+ } else if (new_timer < LONG_MAX) {
+ new_timer += key_gc_delay;
+ key_schedule_gc(new_timer);
+ }
+ kleave(" [end]");
}