From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 E5A4634EEE6 for ; Wed, 4 Mar 2026 16:12:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772640780; cv=none; b=nobTP5tSSKDyYQ7OxhVZeDBf7yQjne7PTe9HAD7kMiM6223xETe6lWLVZgw9sCP2tCp7TEJKqXh6UV109U8mGtdPVj8NOstvSqfRelw+dUpPtrPyuzxNsfdRJGwzlm7OTU9sWv8hOR41IWJpUcuj/BDE5WEHx7bwJwLjgHaGOR0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772640780; c=relaxed/simple; bh=rsHp/hWLfBky2bod2rEdUSenhxUBDI4ThZQMxY0D/C4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=l59DyJzYbUW/uf3CFP6a+pe9Usvy0l/I7+NE0rqaqv6EBvm9DMxRByGfLXHG0epS7m/aebIb1diJ4nwQ4iwo4TVO2yLvIjzzydYCHP9jEYIMUE7enUU5hMUAH4s/LOtooe6Sqxtz0h1JDSxb/GV2b1nM5Y/V/jOlCmKZluyxem0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Jpe80b+V; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=8qjQh9sq; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Jpe80b+V"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="8qjQh9sq" Date: Wed, 4 Mar 2026 17:12:55 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1772640777; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1PpzMbztFZA1/pZs42tjh+yx+ZIqVPB+IHx+8JNsO4w=; b=Jpe80b+V6sDOF0X/ozmuPLPpulzdbJ3DbND1u27RfYZXXeYSBeciPrJ+CD3pO1CA65SBUO 2mNUMXYwP78EUM14bGQKOY0EqPQj+DVjJnWqCUtgRVBjaIzHoIrvpXNwVQDPoHar+dfNKP NdvNzMMGTDIC/C25/jea5/ldNtE4Ah/fN8YsW2GqRnw9EvFbcrSMK3QYa7IQy+O6rbHmXH bc3pH/gNqJBw6+wM4u09YF5uCDv4RFF6hrEDhq8OGAm7ZwznrfKsWWmC+3J2HvDOyVy3C2 8WLFq37ulrDqQd0dPBMbYGDftHAM6ELj+nQccwPPQS2aUIIWJxnyJ9/lycufbA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1772640777; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1PpzMbztFZA1/pZs42tjh+yx+ZIqVPB+IHx+8JNsO4w=; b=8qjQh9sqfspb+xhV0fibdRj79R85/ExvBHKP/VPvOYRNdAL2t/S1CCJQnMwxTZZ/KgcavU 3f1G+Yf84cUA29Aw== From: Sebastian Andrzej Siewior To: Willem de Bruijn Cc: netdev@vger.kernel.org, Andrew Lunn , "David S . Miller" , Eric Dumazet , Felix Maurer , Jakub Kicinski , Paolo Abeni , Richard Cochran , Simon Horman Subject: Re: [PATCH RFC net-next 1/2] hsr: Allow to send a specific port and with HSR header Message-ID: <20260304161255.VV_7vPBw@linutronix.de> References: <20260204-hsr_ptp-v1-0-b421c69a77da@linutronix.de> <20260204-hsr_ptp-v1-1-b421c69a77da@linutronix.de> <20260304145821.TQhzhhjF@linutronix.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On 2026-03-04 10:56:16 [-0500], Willem de Bruijn wrote: > Sebastian Andrzej Siewior wrote: > > Would it be okay if I occupy three bits in sk_buff which look unused? > > Have you looked into using skb_extensions? Yes. I would have allocate memory via __skb_ext_alloc() and attach it to the skb via __skb_ext_set(). That would on receive and while sending (via af_packet). Looking at the current allocations as of skb_ext_type_len, they all need a bit of memory, the smallest is mctp_flow with just a pointer the other are a fair amount larger. For the three bits, I was hoping to avoid it. Sebastian