On Sun, Dec 13, 2020 at 03:29:38PM +0200, Leon Romanovsky wrote:
> From: Shay Drory <shayd@xxxxxxxxxx>
>
> Currently, polling a umad device will always works, even if the device
> was disassociated. Hence, returning EPOLLERR if device was
> disassociated.
Grammar:
Currently, polling a umad device will always work, even if the device was
disassociated. A disassociated device should immediately return EPOLLERR
from poll() and EIO from any read()/write(). Otherwise userspace is
endlessly hung on poll() with no idea that the device has been removed
from the system.
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Shay Drory <shayd@xxxxxxxxxx>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
> drivers/infiniband/core/user_mad.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c
> index b671d4aede77..6681e9cf8a18 100644
> +++ b/drivers/infiniband/core/user_mad.c
> @@ -653,10 +653,14 @@ static __poll_t ib_umad_poll(struct file *filp, struct poll_table_struct *wait)
> /* we will always be able to post a MAD send */
> __poll_t mask = EPOLLOUT | EPOLLWRNORM;
>
> + mutex_lock(&file->mutex);
> poll_wait(filp, &file->recv_wait, wait);
>
> if (!list_empty(&file->recv_list))
> mask |= EPOLLIN | EPOLLRDNORM;
> + if (file->agents_dead)
> + mask = EPOLLERR;
This also needs to trigger the recv_wait when agents_dead is set in
ib_umad_kill_port()
Jason
