RDMA/uverbs: Make the event_queue fds return POLLERR when disassociated

[ Upstream commit eb356e6dc15a30af604f052cd0e170450193c254 ]

If is_closed is set, and the event list is empty, then read() will return
-EIO without blocking. After setting is_closed in
ib_uverbs_free_event_queue(), we do trigger a wake_up on the poll_wait,
but the fops->poll() function does not check it, so poll will continue to
sleep on an empty list.

Fixes: 14e23bd6d221 ("RDMA/core: Fix locking in ib_uverbs_event_read")
Link: https://lore.kernel.org/r/0-v1-ace813388969+48859-uverbs_poll_fix%25jgg@mellanox.com
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index f2a2d12..adb08c3 100644 (file)
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -307,6 +307,8 @@ static __poll_t ib_uverbs_event_poll(struct ib_uverbs_event_queue *ev_queue,
        spin_lock_irq(&ev_queue->lock);
        if (!list_empty(&ev_queue->event_list))
                pollflags = EPOLLIN | EPOLLRDNORM;
+       else if (ev_queue->is_closed)
+               pollflags = EPOLLERR;
        spin_unlock_irq(&ev_queue->lock);
 
        return pollflags;