diff options
Diffstat (limited to 'security/keys/gc.c')
| -rw-r--r-- | security/keys/gc.c | 78 |
1 files changed, 51 insertions, 27 deletions
diff --git a/security/keys/gc.c b/security/keys/gc.c index 1e616aef55fd..485fc6233c38 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]"); } |