diff options
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index d33f52cd437..2faeef28c20 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -441,7 +441,7 @@ static struct entropy_store nonblocking_pool = { /* * This function adds bytes into the entropy "pool". It does not * update the entropy estimate. The caller should call - * credit_entropy_store if this is appropriate. + * credit_entropy_bits if this is appropriate. * * The pool is stirred with a primitive polynomial of the appropriate * degree, and then twisted. We twist by three bits at a time because @@ -515,24 +515,22 @@ static void mix_pool_bytes(struct entropy_store *r, const void *in, int bytes) /* * Credit (or debit) the entropy store with n bits of entropy */ -static void credit_entropy_store(struct entropy_store *r, int nbits) +static void credit_entropy_bits(struct entropy_store *r, int nbits) { unsigned long flags; + if (!nbits) + return; + spin_lock_irqsave(&r->lock, flags); - if (r->entropy_count + nbits < 0) { - DEBUG_ENT("negative entropy/overflow (%d+%d)\n", - r->entropy_count, nbits); + DEBUG_ENT("added %d entropy credits to %s\n", nbits, r->name); + r->entropy_count += nbits; + if (r->entropy_count < 0) { + DEBUG_ENT("negative entropy/overflow\n"); r->entropy_count = 0; - } else if (r->entropy_count + nbits > r->poolinfo->POOLBITS) { + } else if (r->entropy_count > r->poolinfo->POOLBITS) r->entropy_count = r->poolinfo->POOLBITS; - } else { - r->entropy_count += nbits; - if (nbits) - DEBUG_ENT("added %d entropy credits to %s\n", - nbits, r->name); - } /* should we wake readers? */ if (r == &input_pool && r->entropy_count >= random_read_wakeup_thresh) @@ -619,8 +617,8 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num) * Round down by 1 bit on general principles, * and limit entropy entimate to 12 bits. */ - credit_entropy_store(&input_pool, - min_t(int, fls(delta>>1), 11)); + credit_entropy_bits(&input_pool, + min_t(int, fls(delta>>1), 11)); } out: preempt_enable(); @@ -702,7 +700,7 @@ static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes) bytes = extract_entropy(r->pull, tmp, bytes, random_read_wakeup_thresh / 8, rsvd); mix_pool_bytes(r, tmp, bytes); - credit_entropy_store(r, bytes*8); + credit_entropy_bits(r, bytes*8); } } @@ -1073,7 +1071,7 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) return -EPERM; if (get_user(ent_count, p)) return -EFAULT; - credit_entropy_store(&input_pool, ent_count); + credit_entropy_bits(&input_pool, ent_count); return 0; case RNDADDENTROPY: if (!capable(CAP_SYS_ADMIN)) @@ -1088,7 +1086,7 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) size); if (retval < 0) return retval; - credit_entropy_store(&input_pool, ent_count); + credit_entropy_bits(&input_pool, ent_count); return 0; case RNDZAPENTCNT: case RNDCLEARPOOL: |