diff options
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 38 |
1 files changed, 19 insertions, 19 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index c1763bcbcaed..0bb3d7cf33e5 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -71,16 +71,16 @@ *********************************************************************/ /* - * crng_init = 0 --> Uninitialized - * 1 --> Initialized - * 2 --> Initialized from input_pool - * * crng_init is protected by base_crng->lock, and only increases - * its value (from 0->1->2). + * its value (from empty->early->ready). */ -static int crng_init = 0; -#define crng_ready() (likely(crng_init > 1)) -/* Various types of waiters for crng_init->2 transition. */ +static enum { + CRNG_EMPTY = 0, /* Little to no entropy collected */ + CRNG_EARLY = 1, /* At least POOL_EARLY_BITS collected */ + CRNG_READY = 2 /* Fully initialized with POOL_READY_BITS collected */ +} crng_init = CRNG_EMPTY; +#define crng_ready() (likely(crng_init >= CRNG_READY)) +/* Various types of waiters for crng_init->CRNG_READY transition. */ static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait); static struct fasync_struct *fasync; static DEFINE_SPINLOCK(random_ready_chain_lock); @@ -283,7 +283,7 @@ static void crng_reseed(void) WRITE_ONCE(base_crng.generation, next_gen); WRITE_ONCE(base_crng.birth, jiffies); if (!crng_ready()) { - crng_init = 2; + crng_init = CRNG_READY; finalize_init = true; } spin_unlock_irqrestore(&base_crng.lock, flags); @@ -377,7 +377,7 @@ static void crng_make_state(u32 chacha_state[CHACHA_STATE_WORDS], * For the fast path, we check whether we're ready, unlocked first, and * then re-check once locked later. In the case where we're really not * ready, we do fast key erasure with the base_crng directly, extracting - * when crng_init==0. + * when crng_init is CRNG_EMPTY. */ if (!crng_ready()) { bool ready; @@ -385,7 +385,7 @@ static void crng_make_state(u32 chacha_state[CHACHA_STATE_WORDS], spin_lock_irqsave(&base_crng.lock, flags); ready = crng_ready(); if (!ready) { - if (crng_init == 0) + if (crng_init == CRNG_EMPTY) extract_entropy(base_crng.key, sizeof(base_crng.key)); crng_fast_key_erasure(base_crng.key, chacha_state, random_data, random_data_len); @@ -739,8 +739,8 @@ EXPORT_SYMBOL(get_random_bytes_arch); enum { POOL_BITS = BLAKE2S_HASH_SIZE * 8, - POOL_INIT_BITS = POOL_BITS, /* No point in settling for less. */ - POOL_FAST_INIT_BITS = POOL_INIT_BITS / 2 + POOL_READY_BITS = POOL_BITS, /* When crng_init->CRNG_READY */ + POOL_EARLY_BITS = POOL_READY_BITS / 2 /* When crng_init->CRNG_EARLY */ }; static struct { @@ -835,13 +835,13 @@ static void credit_init_bits(size_t nbits) init_bits = min_t(unsigned int, POOL_BITS, orig + add); } while (cmpxchg(&input_pool.init_bits, orig, init_bits) != orig); - if (!crng_ready() && init_bits >= POOL_INIT_BITS) + if (!crng_ready() && init_bits >= POOL_READY_BITS) crng_reseed(); - else if (unlikely(crng_init == 0 && init_bits >= POOL_FAST_INIT_BITS)) { + else if (unlikely(crng_init == CRNG_EMPTY && init_bits >= POOL_EARLY_BITS)) { spin_lock_irqsave(&base_crng.lock, flags); - if (crng_init == 0) { + if (crng_init == CRNG_EMPTY) { extract_entropy(base_crng.key, sizeof(base_crng.key)); - crng_init = 1; + crng_init = CRNG_EARLY; } spin_unlock_irqrestore(&base_crng.lock, flags); } @@ -1610,7 +1610,7 @@ const struct file_operations urandom_fops = { * * - write_wakeup_threshold - the amount of entropy in the input pool * below which write polls to /dev/random will unblock, requesting - * more entropy, tied to the POOL_INIT_BITS constant. It is writable + * more entropy, tied to the POOL_READY_BITS constant. It is writable * to avoid breaking old userspaces, but writing to it does not * change any behavior of the RNG. * @@ -1625,7 +1625,7 @@ const struct file_operations urandom_fops = { #include <linux/sysctl.h> static int sysctl_random_min_urandom_seed = CRNG_RESEED_INTERVAL / HZ; -static int sysctl_random_write_wakeup_bits = POOL_INIT_BITS; +static int sysctl_random_write_wakeup_bits = POOL_READY_BITS; static int sysctl_poolsize = POOL_BITS; static u8 sysctl_bootid[UUID_SIZE]; |