On 2/11/20 1:22 PM, Pavel Begunkov wrote:
>> @@ -3692,15 +3738,33 @@ static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
>> struct poll_table_struct *p)
>> {
>> struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
>> + struct io_kiocb *req = pt->req;
>> + struct io_poll_iocb *poll = &req->poll;
>>
>> - if (unlikely(pt->req->poll.head)) {
>> - pt->error = -EINVAL;
>> - return;
>> + /*
>> + * If poll->head is already set, it's because the file being polled
>> + * use multiple waitqueues for poll handling (eg one for read, one
>> + * for write). Setup a separate io_poll_iocb if this happens.
>> + */
>> + if (unlikely(poll->head)) {
>
> I'll keep looking, but I guess there should be :
>
> if (req->io)
> return -EINVAL;
Yes, I've changed it to:
if (unlikely(poll->head)) {
/* already have a 2nd entry, fail a third attempt */
if (req->io) {
pt->error = -EINVAL;
return;
}
poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
if (!poll) {
pt->error = -ENOMEM;
return;
}
[...]
--
Jens Axboe
