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 A11F23C466; Thu, 14 Nov 2024 15:02:36 +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=1731596556; cv=none; b=Q73jbEdNguIkkTspYd13/+sPB9xlpOli5GBlaGtrIcsIt7lZQNCjRrgpNFh2DJCKFIyL+bZsP6r35QtXu+Xh0AO5ZX8GxmkQ6casn22K2jHfZa97/PSZK/0TrRuDMC5XNBrygD+c4oB7KFyD15k/fLzI+9pM3aP0OVXqUMEIvGE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731596556; c=relaxed/simple; bh=dN4tvL3q9pcjFqSpwP8uKkrWWNaEeL9R+qbXlxvJ5G8=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Ni4JPW9KBwbpQfZKSAHCt/+FJlgNTELhJ5cCfihUIrlVa4vwPQJramQ/zKEw6RffCnRhBGtm4LRbjkmR8brXssfrWB2jwNj4H26N+21iDdtzkVdhYHAeVKUbGAhpIkm60sNeUkuMD3NiROIlMNyF+Qyy//CBnWYTkCcOCOnyPc8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WOVs1XoT; 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="WOVs1XoT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A2D3C4CECD; Thu, 14 Nov 2024 15:02:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731596556; bh=dN4tvL3q9pcjFqSpwP8uKkrWWNaEeL9R+qbXlxvJ5G8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=WOVs1XoTZNNbTwcON3ExJl0NUWwZHgdMAROCIprysZMcxVLF215tsGcnP13WdCHxx +2f+9wr+kfk5dYY/V1gIGg7Db6voSlLXymnJ0YkUtFoo6OIOzph/hO4HNjHswqksBK xYg88qZHfVFVxv758KXVCys0hIsRuq4Q18inblgZqFixbNx7hD4h+OOntrpvUvdnab WJRYGmkcKrBbF/iTfd5XpEgrZJqFtvxR6t+nDg3KxTSTXEBJ/nCGhTwkhoMcKy+azo Rpo/65vWkT2H3qpJD8krVr6LESHH3NTB+NkGYmlw5RojqOXtenhaPjQIVbjC2VACoX o71rNQakFzwTg== Date: Thu, 14 Nov 2024 07:02:35 -0800 From: Jakub Kicinski To: Marc Kleine-Budde Cc: Jeremy Kerr , Jian Zhang , netdev@vger.kernel.org, openbmc@lists.ozlabs.org, Matt Johnston , "David S. Miller" , Eric Dumazet , Paolo Abeni , open list Subject: Re: [PATCH net-next] mctp i2c: notify user space on TX failure Message-ID: <20241114070235.79f9a429@kernel.org> In-Reply-To: <42761fa6276dcfc64f961d25ff7a46b764d35851.camel@codeconstruct.com.au> References: <20241108094206.2808293-1-zhangjian.3032@bytedance.com> <20241113190920.0ceaddf2@kernel.org> <20241113191909.10cf495e@kernel.org> <42761fa6276dcfc64f961d25ff7a46b764d35851.camel@codeconstruct.com.au> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 14 Nov 2024 14:48:57 +0800 Jeremy Kerr wrote: > > routing isn't really my forte, TBH, what eats the error so that it > > doesn't come out of mctp_local_output() ? Do you use qdiscs on top > > of the MCTP devices? > > There are no qdiscs involved at this stage, as we need to preserve > packet ordering in most cases. The route output functions will end up > in a dev_queue_xmit, so any tx error would have been decoupled from the > route output at that stage. Ah, it's the driver eating the errors, it puts the packet on a local queue and returns OK no matter what. The I2C transfer happens from a thread. I wonder if there is precedent, let's ask CAN experts. Mark, MCTP would like to report errors from the drivers all the way to the socket. Do CAN drivers do something along these lines?