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| author | Christoph Hellwig <hch@lst.de> | 2018-04-09 16:29:32 +0300 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2018-05-26 10:16:44 +0300 |
| commit | 89b310a2b28dafbf3958e292785d51b7017da19e (patch) | |
| tree | 4f25de40325970925691d0b9fcc60ad7d5b6ac14 /drivers/char | |
| parent | 652fe8e87621d95a94edd25a08d5754abd878161 (diff) | |
| download | linux-89b310a2b28dafbf3958e292785d51b7017da19e.tar.xz | |
random: convert to ->poll_mask
The big change is that random_read_wait and random_write_wait are merged
into a single waitqueue that uses keyed wakeups. Because wait_event_*
doesn't know about that this will lead to occassional spurious wakeups
in _random_read and add_hwgenerator_randomness, but wait_event_* is
designed to handle these and were are not in a a hot path there.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index cd888d4ee605..a8fb0020ba5c 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -402,8 +402,7 @@ static struct poolinfo { /* * Static global variables */ -static DECLARE_WAIT_QUEUE_HEAD(random_read_wait); -static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); +static DECLARE_WAIT_QUEUE_HEAD(random_wait); static struct fasync_struct *fasync; static DEFINE_SPINLOCK(random_ready_list_lock); @@ -722,8 +721,8 @@ retry: /* should we wake readers? */ if (entropy_bits >= random_read_wakeup_bits && - wq_has_sleeper(&random_read_wait)) { - wake_up_interruptible(&random_read_wait); + wq_has_sleeper(&random_wait)) { + wake_up_interruptible_poll(&random_wait, POLLIN); kill_fasync(&fasync, SIGIO, POLL_IN); } /* If the input pool is getting full, send some @@ -1397,7 +1396,7 @@ retry: trace_debit_entropy(r->name, 8 * ibytes); if (ibytes && (r->entropy_count >> ENTROPY_SHIFT) < random_write_wakeup_bits) { - wake_up_interruptible(&random_write_wait); + wake_up_interruptible_poll(&random_wait, POLLOUT); kill_fasync(&fasync, SIGIO, POLL_OUT); } @@ -1839,7 +1838,7 @@ _random_read(int nonblock, char __user *buf, size_t nbytes) if (nonblock) return -EAGAIN; - wait_event_interruptible(random_read_wait, + wait_event_interruptible(random_wait, ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits); if (signal_pending(current)) @@ -1876,14 +1875,17 @@ urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) return ret; } +static struct wait_queue_head * +random_get_poll_head(struct file *file, __poll_t events) +{ + return &random_wait; +} + static __poll_t -random_poll(struct file *file, poll_table * wait) +random_poll_mask(struct file *file, __poll_t events) { - __poll_t mask; + __poll_t mask = 0; - poll_wait(file, &random_read_wait, wait); - poll_wait(file, &random_write_wait, wait); - mask = 0; if (ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits) mask |= EPOLLIN | EPOLLRDNORM; if (ENTROPY_BITS(&input_pool) < random_write_wakeup_bits) @@ -1990,7 +1992,8 @@ static int random_fasync(int fd, struct file *filp, int on) const struct file_operations random_fops = { .read = random_read, .write = random_write, - .poll = random_poll, + .get_poll_head = random_get_poll_head, + .poll_mask = random_poll_mask, .unlocked_ioctl = random_ioctl, .fasync = random_fasync, .llseek = noop_llseek, @@ -2323,7 +2326,7 @@ void add_hwgenerator_randomness(const char *buffer, size_t count, * We'll be woken up again once below random_write_wakeup_thresh, * or when the calling thread is about to terminate. */ - wait_event_interruptible(random_write_wait, kthread_should_stop() || + wait_event_interruptible(random_wait, kthread_should_stop() || ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits); mix_pool_bytes(poolp, buffer, count); credit_entropy_bits(poolp, entropy); |