From patchwork Tue Dec 19 21:03:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Wei X-Patchwork-Id: 13499107 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-pl1-f174.google.com (mail-pl1-f174.google.com [209.85.214.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E50AB3EA7A for ; Tue, 19 Dec 2023 21:04:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=davidwei.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=davidwei.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=davidwei-uk.20230601.gappssmtp.com header.i=@davidwei-uk.20230601.gappssmtp.com header.b="dCsXqDtQ" Received: by mail-pl1-f174.google.com with SMTP id d9443c01a7336-1d3ce28ac3cso16788035ad.0 for ; Tue, 19 Dec 2023 13:04:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=davidwei-uk.20230601.gappssmtp.com; s=20230601; t=1703019860; x=1703624660; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=GxpOp5keoBQGOz00dSxKjcoORly3Uq6QcOZ8S/MSAKQ=; b=dCsXqDtQQRdS3qE2x27ZjDcAt67Sxxj3q5igk7TxkZ7nIOZpby+uKKUQVB4gyTNR2B d/L3Wpryht4RLo4k/VLZvzmRNzmt5fUat5grHDhOtZgChXjsR5otxIYKad4XuUJyY0Fk zx0b8m/zhlm9lzDjzaosaAtMzmQ4BWFP7oaZccY2Z4/vpXsfE8yEcycYeI6k8YK25iHd GWbnI3Wx4fwBP/OAD9HUMlgpNmm0kna8DXXEVjtzE67UZtOZxo10aXK3Dj2XqMzJDHSd xxlnPBXLh7ACFeLSdSXiB+sbaDE6l13TnIDlTzitzRhwD17Sy6gYrLqhODabsWHvzvp9 kq3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703019860; x=1703624660; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=GxpOp5keoBQGOz00dSxKjcoORly3Uq6QcOZ8S/MSAKQ=; b=RvgTHrMzGfB4W4Igw3Zw+HzTH39MS2/g0wghvSZyQ5wexXd7+wtQmXZesKu3uF5gE7 eRpB0LQ6m5hF9hGQOgRYRMsUHoDl2KcBA3Qt/qLzZMw73d/udv4UYvKNEKl0A4tO7jnZ c9LkLjFEva67ROE5+kqoO0KT4cZGEaV3eEiE3vyy5GL4Yh2LvAf0TgdxxNacXEQN6+r5 AjbZohcVG0Q0aicXhq3MuOB5Nq7J0AB+ZHbRcGeA/o6BMNdJEWd+F469eSTxfnoxoV5N huJ1BJriVL+g0Kxbc81NawJglBlNCfqWE7+fWuntinwI7bKlu6HjWEyjfIkPdBcPOJEo EGcg== X-Gm-Message-State: AOJu0YxjuFZJb2cCGFCk2AZC3UaMUq8K+Ajr3Xtv9I1H/deh+u1owEgA ePi9xxIA6vGNLOu6tKMyImOQrw== X-Google-Smtp-Source: AGHT+IGggFl0JrUM4oTE/WqbU6Jj7xNuoLiaUQdJMih11dS+6jNAD97QTKlC1myhDJGi0F2OblMPZQ== X-Received: by 2002:a17:903:11c5:b0:1d0:6ffd:8367 with SMTP id q5-20020a17090311c500b001d06ffd8367mr9469743plh.114.1703019860208; Tue, 19 Dec 2023 13:04:20 -0800 (PST) Received: from localhost (fwdproxy-prn-013.fbsv.net. [2a03:2880:ff:d::face:b00c]) by smtp.gmail.com with ESMTPSA id l5-20020a170903120500b001d349fcb70dsm12563264plh.202.2023.12.19.13.04.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Dec 2023 13:04:19 -0800 (PST) From: David Wei To: io-uring@vger.kernel.org, netdev@vger.kernel.org Cc: Jens Axboe , Pavel Begunkov , Jakub Kicinski , Paolo Abeni , "David S. Miller" , Eric Dumazet , Jesper Dangaard Brouer , David Ahern , Mina Almasry Subject: [RFC PATCH v3 16/20] net: execute custom callback from napi Date: Tue, 19 Dec 2023 13:03:53 -0800 Message-Id: <20231219210357.4029713-17-dw@davidwei.uk> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20231219210357.4029713-1-dw@davidwei.uk> References: <20231219210357.4029713-1-dw@davidwei.uk> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC From: Pavel Begunkov Sometimes we want to access a napi protected resource from task context like in the case of io_uring zc falling back to copy and accessing the buffer ring. Add a helper function that allows to execute a custom function from napi context by first stopping it similarly to napi_busy_loop(). Experimental, needs much polishing and sharing bits with napi_busy_loop(). Signed-off-by: Pavel Begunkov Signed-off-by: David Wei --- include/net/busy_poll.h | 7 +++++++ net/core/dev.c | 46 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+) diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h index 4dabeb6c76d3..64238467e00a 100644 --- a/include/net/busy_poll.h +++ b/include/net/busy_poll.h @@ -47,6 +47,8 @@ bool sk_busy_loop_end(void *p, unsigned long start_time); void napi_busy_loop(unsigned int napi_id, bool (*loop_end)(void *, unsigned long), void *loop_end_arg, bool prefer_busy_poll, u16 budget); +void napi_execute(struct napi_struct *napi, + void (*cb)(void *), void *cb_arg); #else /* CONFIG_NET_RX_BUSY_POLL */ static inline unsigned long net_busy_loop_on(void) @@ -59,6 +61,11 @@ static inline bool sk_can_busy_loop(struct sock *sk) return false; } +static inline void napi_execute(struct napi_struct *napi, + void (*cb)(void *), void *cb_arg) +{ +} + #endif /* CONFIG_NET_RX_BUSY_POLL */ static inline unsigned long busy_loop_current_time(void) diff --git a/net/core/dev.c b/net/core/dev.c index e55750c47245..2dd4f3846535 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6537,6 +6537,52 @@ void napi_busy_loop(unsigned int napi_id, } EXPORT_SYMBOL(napi_busy_loop); +void napi_execute(struct napi_struct *napi, + void (*cb)(void *), void *cb_arg) +{ + bool done = false; + unsigned long val; + void *have_poll_lock = NULL; + + rcu_read_lock(); + + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); + for (;;) { + local_bh_disable(); + val = READ_ONCE(napi->state); + + /* If multiple threads are competing for this napi, + * we avoid dirtying napi->state as much as we can. + */ + if (val & (NAPIF_STATE_DISABLE | NAPIF_STATE_SCHED | + NAPIF_STATE_IN_BUSY_POLL)) + goto restart; + + if (cmpxchg(&napi->state, val, + val | NAPIF_STATE_IN_BUSY_POLL | + NAPIF_STATE_SCHED) != val) + goto restart; + + have_poll_lock = netpoll_poll_lock(napi); + cb(cb_arg); + done = true; + gro_normal_list(napi); + local_bh_enable(); + break; +restart: + local_bh_enable(); + if (unlikely(need_resched())) + break; + cpu_relax(); + } + if (done) + busy_poll_stop(napi, have_poll_lock, false, 1); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); + rcu_read_unlock(); +} + #endif /* CONFIG_NET_RX_BUSY_POLL */ static void napi_hash_add(struct napi_struct *napi)