Re: [PATCH net-next 3/3] net: qrtr: implement shutdown()

[Manivannan Sadhasivam <mani@kernel.org>]

On Fri, Oct 16, 2026 at 01:58:20AM -0700, Chunkai Deng wrote:
> QRTR uses sock_no_shutdown(), so shutdown() fails with -EOPNOTSUPP and
> there is no way to wake up a thread blocked in recv() on the socket.
> 
> Implement it the same way as unix_shutdown(): map SHUT_* to the
> *_SHUTDOWN bits, set them in sk_shutdown and call sk_state_change().
> 
> Do not use lock_sock() here. qrtr_sendmsg() holds it while sleeping in
> qrtr_tx_wait() until the remote returns flow control credit, which would
> leave shutdown() stuck in an uninterruptible wait. Take sk_lock.slock to
> serialize concurrent callers instead, and use WRITE_ONCE() for the
> lockless readers. Do the same for the store in qrtr_release().
> 
> A sender already sleeping in qrtr_tx_wait() is not woken by SHUT_WR;
> later sendmsg() calls fail with -EPIPE.
> 
> Signed-off-by: Chunkai Deng <chunkai.deng@oss.qualcomm.com>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

- Mani

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