Prevents threads from looping indefinitely

[chenhongjun]

When the iscsi client is powered off, the tgt socket has not finished sending data in the kernel, and the thread will loop indefinitely

[fujita]

You meant in such case, write() still returns EAGAIN or EINTR instead of EIO?

[chenhongjun]

You meant in such case, write() still returns EAGAIN or EINTR instead of EIO?

Yes. When the kernel sends the buffer full, the kernel tries asynchronous sending and timeout retransmission, while the tgtd process keeps calling the non-blocking send function, returning EAGAIN each time