summaryrefslogtreecommitdiff
path: root/lib
diff options
context:
space:
mode:
Diffstat (limited to 'lib')
-rw-r--r--lib/Makefile3
-rw-r--r--lib/once.c62
-rw-r--r--lib/random32.c37
3 files changed, 85 insertions, 17 deletions
diff --git a/lib/Makefile b/lib/Makefile
index 13a7c6ae3fec..8de3b012eac7 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -26,7 +26,8 @@ obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \
gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \
bsearch.o find_bit.o llist.o memweight.o kfifo.o \
- percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o
+ percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o \
+ once.o
obj-y += string_helpers.o
obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
obj-y += hexdump.o
diff --git a/lib/once.c b/lib/once.c
new file mode 100644
index 000000000000..05c8604627eb
--- /dev/null
+++ b/lib/once.c
@@ -0,0 +1,62 @@
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/once.h>
+#include <linux/random.h>
+
+struct once_work {
+ struct work_struct work;
+ struct static_key *key;
+};
+
+static void once_deferred(struct work_struct *w)
+{
+ struct once_work *work;
+
+ work = container_of(w, struct once_work, work);
+ BUG_ON(!static_key_enabled(work->key));
+ static_key_slow_dec(work->key);
+ kfree(work);
+}
+
+static void once_disable_jump(struct static_key *key)
+{
+ struct once_work *w;
+
+ w = kmalloc(sizeof(*w), GFP_ATOMIC);
+ if (!w)
+ return;
+
+ INIT_WORK(&w->work, once_deferred);
+ w->key = key;
+ schedule_work(&w->work);
+}
+
+static DEFINE_SPINLOCK(once_lock);
+
+bool __do_once_start(bool *done, unsigned long *flags)
+ __acquires(once_lock)
+{
+ spin_lock_irqsave(&once_lock, *flags);
+ if (*done) {
+ spin_unlock_irqrestore(&once_lock, *flags);
+ /* Keep sparse happy by restoring an even lock count on
+ * this lock. In case we return here, we don't call into
+ * __do_once_done but return early in the DO_ONCE() macro.
+ */
+ __acquire(once_lock);
+ return false;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(__do_once_start);
+
+void __do_once_done(bool *done, struct static_key *once_key,
+ unsigned long *flags)
+ __releases(once_lock)
+{
+ *done = true;
+ spin_unlock_irqrestore(&once_lock, *flags);
+ once_disable_jump(once_key);
+}
+EXPORT_SYMBOL(__do_once_done);
diff --git a/lib/random32.c b/lib/random32.c
index 0bee183fa18f..12111910ccd0 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -181,7 +181,7 @@ void prandom_seed(u32 entropy)
* No locking on the CPUs, but then somewhat random results are, well,
* expected.
*/
- for_each_possible_cpu (i) {
+ for_each_possible_cpu(i) {
struct rnd_state *state = &per_cpu(net_rand_state, i);
state->s1 = __seed(state->s1 ^ entropy, 2U);
@@ -201,7 +201,7 @@ static int __init prandom_init(void)
prandom_state_selftest();
for_each_possible_cpu(i) {
- struct rnd_state *state = &per_cpu(net_rand_state,i);
+ struct rnd_state *state = &per_cpu(net_rand_state, i);
u32 weak_seed = (i + jiffies) ^ random_get_entropy();
prandom_seed_early(state, weak_seed, true);
@@ -238,13 +238,30 @@ static void __init __prandom_start_seed_timer(void)
add_timer(&seed_timer);
}
+void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ struct rnd_state *state = per_cpu_ptr(pcpu_state, i);
+ u32 seeds[4];
+
+ get_random_bytes(&seeds, sizeof(seeds));
+ state->s1 = __seed(seeds[0], 2U);
+ state->s2 = __seed(seeds[1], 8U);
+ state->s3 = __seed(seeds[2], 16U);
+ state->s4 = __seed(seeds[3], 128U);
+
+ prandom_warmup(state);
+ }
+}
+
/*
* Generate better values after random number generator
* is fully initialized.
*/
static void __prandom_reseed(bool late)
{
- int i;
unsigned long flags;
static bool latch = false;
static DEFINE_SPINLOCK(lock);
@@ -266,19 +283,7 @@ static void __prandom_reseed(bool late)
goto out;
latch = true;
-
- for_each_possible_cpu(i) {
- struct rnd_state *state = &per_cpu(net_rand_state,i);
- u32 seeds[4];
-
- get_random_bytes(&seeds, sizeof(seeds));
- state->s1 = __seed(seeds[0], 2U);
- state->s2 = __seed(seeds[1], 8U);
- state->s3 = __seed(seeds[2], 16U);
- state->s4 = __seed(seeds[3], 128U);
-
- prandom_warmup(state);
- }
+ prandom_seed_full_state(&net_rand_state);
out:
spin_unlock_irqrestore(&lock, flags);
}