From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0B84044C8F; Thu, 12 Sep 2024 15:26:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726154774; cv=none; b=TLbTnTGtlIWqi3d4vqc0hHMVFaraNnlG5JcO5KNM1eroNHDKP1OGTIh7jxvPcE2RePnuvdTx4Z3pG7CCrCOTnTsuPxESCgEo/9NqYznr7BxwIBz9U4WljhoynqacDKXASsfzsXwNqiSaC/6RM+jmqXEIjHYVHoQtUeGADdSy83E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726154774; c=relaxed/simple; bh=eT5iKufiEqBrOOHnVVD75u4spQv2bu9zWq9lPSq8HXQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kJFZPeDBme2cs801sPs+f97uARdrrbML8YMqr4AwqPtqaizSPBftpDjCVnknGZ6XOnEE1ZnYGPRWZ3OK/iLBr1o5TJLaNcNaNaKNqjk839BVIWmJqRGzdmFfyOsbgCygjqkye+OuQztSTV2GQEBG6mBFQVavZ+Ug0A+Ehqow6Tg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=a2/oqNWI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="a2/oqNWI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DF6AC4CEC3; Thu, 12 Sep 2024 15:26:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726154773; bh=eT5iKufiEqBrOOHnVVD75u4spQv2bu9zWq9lPSq8HXQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=a2/oqNWImsRF63TtKZfRJokrnQh4veCjTbq8hYaoS9r9/Yla+QR4K3v5VSPGCCS0i +yoIRYu5jYInrsMx4sav4baIgWZoq2sBsmviRHLGnm/HKuIgMAgA8GLOp4ipAeJZZC 3ZhR/LjYn8m1a1NLPKFYxeMmnGPmZzKhbmtHxqy/CIbNjMpwZy9HdPz9hMAlpBZAjl g62bFol1VIR/rCH2bMlqFDbj7IOQlltbhGCbDfPggFVZ0spBs+f/vLCm6Hf6ynSBX2 6Yu4zhB7Bq2QHE4aLFsinS9rgN5mIoyQ8YO4jzFEC+1wabGY8125ICWZFUwZWav4PN dilesEWC9lkOg== Message-ID: <73a104e0-d73f-4836-92fd-4bef415900d4@kernel.org> Date: Thu, 12 Sep 2024 17:26:09 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net-next] memory-provider: fix compilation issue without SYSFS Content-Language: en-GB To: Mina Almasry Cc: mptcp@lists.linux.dev, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Kaiyuan Zhang , Willem de Bruijn , Pavel Begunkov , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20240912-net-next-fix-get_netdev_rx_queue_index-v1-1-d73a1436be8c@kernel.org> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Mina, Thank you for your reply! On 12/09/2024 14:49, Mina Almasry wrote: > On Thu, Sep 12, 2024 at 3:25 AM Matthieu Baerts (NGI0) > wrote: >> >> When CONFIG_SYSFS is not set, the kernel fails to compile: >> >> net/core/page_pool_user.c:368:45: error: implicit declaration of function 'get_netdev_rx_queue_index' [-Werror=implicit-function-declaration] >> 368 | if (pool->slow.queue_idx == get_netdev_rx_queue_index(rxq)) { >> | ^~~~~~~~~~~~~~~~~~~~~~~~~ >> >> When CONFIG_SYSFS is not set, get_netdev_rx_queue_index() is not defined >> as well. In this case, page_pool_check_memory_provider() cannot check >> the memory provider, and a success answer can be returned instead. >> > > Thanks Matthieu, and sorry about that. > > I have reproduced the build error and the fix resolves it. But... > >> Fixes: 0f9214046893 ("memory-provider: dmabuf devmem memory provider") >> Signed-off-by: Matthieu Baerts (NGI0) >> --- >> net/core/page_pool_user.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c >> index 48335766c1bf..a98c0a76b33f 100644 >> --- a/net/core/page_pool_user.c >> +++ b/net/core/page_pool_user.c >> @@ -353,6 +353,7 @@ void page_pool_unlist(struct page_pool *pool) >> int page_pool_check_memory_provider(struct net_device *dev, >> struct netdev_rx_queue *rxq) >> { >> +#ifdef CONFIG_SYSFS >> struct net_devmem_dmabuf_binding *binding = rxq->mp_params.mp_priv; >> struct page_pool *pool; >> struct hlist_node *n; >> @@ -372,6 +373,9 @@ int page_pool_check_memory_provider(struct net_device *dev, >> } >> mutex_unlock(&page_pools_lock); >> return -ENODATA; >> +#else >> + return 0; > > ...we can't assume success when we cannot check the memory provider. > The memory provider check is somewhat critical; we rely on it to > detect that the driver does not support memory providers or is not > doing the right thing, and report that to the user. I don't think we > can silently disable the check when the CONFIG_SYSFS is disabled. > Please return -ENODATA or some other error here. I initially returned 0 to have the same behaviour as when CONFIG_PAGE_POOL is not defined. But thanks to your explanations, I understand it seems better to return -ENODATA here. Or another errno, to let the userspace understanding there is a different error? I can send a v2 after the 24h rate-limit period if you are OK with that. > If we disable devmem TCP for !CONFIG_SYSFS we should probably add > something to the docs saying this. I can do that in a follow up > change. Good point, thank you. > However, I'm looking at the definition of get_netdev_rx_queue_index() > and at first glance I don't see anything there that is actually > dependent on CONFIG_SYSFS. Can we do this instead? I have build-tested > it and it resolves the build issue as well: > > ``` > diff --git a/include/net/netdev_rx_queue.h b/include/net/netdev_rx_queue.h > index ac34f5fb4f71..596836abf7bf 100644 > --- a/include/net/netdev_rx_queue.h > +++ b/include/net/netdev_rx_queue.h > @@ -45,7 +45,6 @@ __netif_get_rx_queue(struct net_device *dev, unsigned int rxq) > return dev->_rx + rxq; > } > > -#ifdef CONFIG_SYSFS > static inline unsigned int > get_netdev_rx_queue_index(struct netdev_rx_queue *queue) > { > @@ -55,7 +54,6 @@ get_netdev_rx_queue_index(struct netdev_rx_queue *queue) > BUG_ON(index >= dev->num_rx_queues); > return index; > } > -#endif > ``` I briefly looked at taking this path when I saw what this helper was doing, but then I saw all operations related to the received queues were enabled only when CONFIG_SYSFS is set, see commit a953be53ce40 ("net-sysfs: add support for device-specific rx queue sysfs attributes"). I understood from that it is better not to look at dev->_rx or dev->num_rx_queues when CONFIG_SYSFS is not set. I'm not very familiar to that part of the code, but it feels like removing this #ifdef might be similar to the "return 0" I suggested: silently disabling the check, no? I *think* it might be clearer to return an error when SYSFS is not set. > Matthieu, I'm happy to follow up with v2 of this fix if you don't have time. If you prefer to explore other ways than returning an error in page_pool_check_memory_provider() when SYSFS is not set, yes please do the follow-up if you don't mind. My main goal is to stop my CI to complain about that when compiling with 'make tinyconfig' + MPTCP :) Cheers, Matt -- Sponsored by the NGI0 Core fund.