Re: [take3 3/4] kevent: Network AIO, socket notifications.

Eric Dumazet
2006-08-03T09:54:31Z

On Thursday 03 August 2006 11:46, Evgeniy Polyakov wrote:
> Network AIO, socket notifications.
>
> This patchset includes socket notifications and network asynchronous IO.
> Network AIO is based on kevent and works as usual kevent storage on top
> of inode.
> (3 * TCP_RTO_MIN) / 4,
> diff --git a/kernel/kevent/kevent_naio.c b/kernel/kevent/kevent_naio.c
+
> +static int kevent_naio_enqueue(struct kevent *k)
> +{
> + int err, i;
> + struct page **page;
> + void *addr;
> + unsigned int size = k->event.id.raw[1];
> + int num = size/PAGE_SIZE;
> + struct file *file;
> + struct sock *sk = NULL;
> + int fput_needed;
> +
> + file = fget_light(k->event.id.raw[0], &fput_needed);
> + if (!file)
> + return -ENODEV;
> +
> + err = -EINVAL;
> + if (!file->f_dentry || !file->f_dentry->d_inode)
> + goto err_out_fput;

How can you be 100% sure this file is actually a socket here ?
(Another thread could close the fd and this fd can now point to another file)

You should do
if (file->f_op != &socket_file_ops)
goto err_out_fput;
sk = file->private_data; /* set in sock_map_fd */

> +
> + sk = SOCKET_I(file->f_dentry->d_inode)->sk;
> +

Eric