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([2a01:4b00:bd21:4f00:7cc6:d3ca:494:116c]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a0018e6dcbsm75325005e9.6.2026.09.27.12.16.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 27 Sep 2026 12:16:18 -0700 (PDT) Message-ID: Date: Sun, 27 Sep 2026 20:16:16 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full To: lollipopkit , Jens Axboe Cc: Willem de Bruijn , io-uring@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260927074206.65427-1-a@lolli.tech> Content-Language: en-US From: Pavel Begunkov In-Reply-To: <20260927074206.65427-1-a@lolli.tech> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/27/26 08:42, lollipopkit wrote: > SOCKET_URING_OP_TX_TIMESTAMP arms an EPOLLERR apoll multishot and, on > each error queue edge, posts one 32 byte aux CQE per timestamp skb. Aux > CQEs have no overflow backing, so io_uring_cmd_post_mshot_cqe32() fails > once the CQ ring is full. The loop then stops, splices the unprocessed > skbs back onto sk_error_queue and returns -EAGAIN. ...> static int io_uring_cmd_timestamp(struct socket *sock, > @@ -135,7 +137,8 @@ static int io_uring_cmd_timestamp(struct socket *sock, > skb = skb_peek(&list); > if (!skb) > break; > - if (!io_process_timestamp_skb(cmd, sk, skb, issue_flags)) > + ret = io_process_timestamp_skb(cmd, sk, skb, issue_flags); > + if (ret) > break; > __skb_dequeue(&list); > consume_skb(skb); > @@ -145,6 +148,12 @@ static int io_uring_cmd_timestamp(struct socket *sock, > scoped_guard(spinlock_irqsave, &q->lock) > skb_queue_splice(&list, q); > } > + /* > + * Aux CQEs cannot overflow and the poll is edge triggered, so nothing > + * re-runs the command once the CQ drains. End the multishot instead. > + */ > + if (ret == -ENOBUFS) > + return -ENOBUFS; I'd make it a 3-state return instead of relying on skb_get_tx_timestamp() not returning specific error codes, but it should be fine for now. Reviewed-by: Pavel Begunkov > return -EAGAIN; > } > > > base-commit: a3bdf68feecc57af5c11fb599f860ac9790ffad9 -- Pavel Begunkov