diff options
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 57 |
1 files changed, 18 insertions, 39 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index fcda7d3937e0..fcc2bff8f887 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1285,53 +1285,32 @@ void rand_initialize_disk(struct gendisk *disk) static ssize_t random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { - ssize_t n, retval = 0, count = 0; + ssize_t n; if (nbytes == 0) return 0; - while (nbytes > 0) { - n = nbytes; - if (n > SEC_XFER_SIZE) - n = SEC_XFER_SIZE; - - n = extract_entropy_user(&blocking_pool, buf, n); - - if (n < 0) { - retval = n; - break; - } - + nbytes = min_t(size_t, nbytes, SEC_XFER_SIZE); + while (1) { + n = extract_entropy_user(&blocking_pool, buf, nbytes); + if (n < 0) + return n; trace_random_read(n*8, (nbytes-n)*8, ENTROPY_BITS(&blocking_pool), ENTROPY_BITS(&input_pool)); - - if (n == 0) { - if (file->f_flags & O_NONBLOCK) { - retval = -EAGAIN; - break; - } - - wait_event_interruptible(random_read_wait, - ENTROPY_BITS(&input_pool) >= - random_read_wakeup_thresh); - - if (signal_pending(current)) { - retval = -ERESTARTSYS; - break; - } - - continue; - } - - count += n; - buf += n; - nbytes -= n; - break; /* This break makes the device work */ - /* like a named pipe */ + if (n > 0) + return n; + /* Pool is (near) empty. Maybe wait and retry. */ + + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + + wait_event_interruptible(random_read_wait, + ENTROPY_BITS(&input_pool) >= + random_read_wakeup_thresh); + if (signal_pending(current)) + return -ERESTARTSYS; } - - return (count ? count : retval); } static ssize_t |