From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-112.freemail.mail.aliyun.com (out30-112.freemail.mail.aliyun.com [115.124.30.112]) (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 BD2EE38E10B for ; Wed, 25 Feb 2026 09:22:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.112 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772011333; cv=none; b=fXQnHHkbnB9d30oH9ahuNF5IacdyoAWvS4uMvwUE/43ryZPkbBQn7ovEDRSh6vXqH44CNhlxT9MEKm5CTklgavHOoXDhoO5DW1zA+Olh+e/cZu5xgTqj4KtAMKO4CCoqQoUOz0fiUC5vSiWevEVBlwGKz6mSW+I76KCDv9y80v4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772011333; c=relaxed/simple; bh=usJdWGjdVWHyoeOFLpeq87JVlSPKqO+60Ixrrf+Cd2w=; h=Message-ID:Subject:Date:From:To:Cc:References:In-Reply-To; b=HtFibpqwL21fVN6JeKCxjSWDV7TTui70Vkee8bP2ektDR6GF1PRNVmRwGsuoF9dekAepLZogl0JyeTDGeY66jdRcZdYwiBaChAwqT8JIZQANzIJSi2d4qgsJpSFnS5iU5WAdzey2KnFhXKPI66HGmsxZF8FJNynf4xquFJkRAds= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=yWlss9bZ; arc=none smtp.client-ip=115.124.30.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="yWlss9bZ" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1772011322; h=Message-ID:Subject:Date:From:To; bh=Jij/vp1VmGg7OCxxZ+6UMDbKQTv+EwP6Pty7TdVomV0=; b=yWlss9bZB1aI9+tW0k6ICUYUgnMs0LTF+W2p5TCp91YEbokbqJQsir9sIU+/wKk7mab8rz63LoxjGIhIukf86PpKs31DtF2Fs1BVjHgsuh1cSSuSnVn34QwzmnBK//2HtFeBIj6O00umXmvGfT0pxO+O26uatGzJk/uu0TtC4SI= Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0Wzm3MxA_1772011321 cluster:ay36) by smtp.aliyun-inc.com; Wed, 25 Feb 2026 17:22:02 +0800 Message-ID: <1772010702.3747633-2-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH net-next,2/2] virtio_net: replace RSS key size max check with BUILD_BUG_ON Date: Wed, 25 Feb 2026 17:11:42 +0800 From: Xuan Zhuo To: Srujana Challa Cc: , , , , , , , , , , , , References: <20260224065850.962826-1-schalla@marvell.com> <20260224065850.962826-2-schalla@marvell.com> In-Reply-To: <20260224065850.962826-2-schalla@marvell.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: On Tue, 24 Feb 2026 12:28:50 +0530, Srujana Challa wrote: > Since NETDEV_RSS_KEY_LEN was increased to 256 in net-next, use > BUILD_BUG_ON to enforce the limit at compile time and remove the > redundant runtime max check. > > Signed-off-by: Srujana Challa > --- > drivers/net/virtio_net.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index eeefe8abc122..768ad5523dfa 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -6639,13 +6639,7 @@ static int virtnet_validate(struct virtio_device *vdev) > __virtio_clear_bit(vdev, VIRTIO_NET_F_RSS); > __virtio_clear_bit(vdev, VIRTIO_NET_F_HASH_REPORT); > } > - if (key_sz > NETDEV_RSS_KEY_LEN) { > - dev_warn(&vdev->dev, > - "rss_max_key_size=%u exceeds driver limit %u, disabling RSS\n", > - key_sz, NETDEV_RSS_KEY_LEN); > - __virtio_clear_bit(vdev, VIRTIO_NET_F_RSS); > - __virtio_clear_bit(vdev, VIRTIO_NET_F_HASH_REPORT); > - } > + BUILD_BUG_ON(type_max(key_sz) >= NETDEV_RSS_KEY_LEN); Do we really need this check? If I understand correctly, the intention is to cap key_sz at 256. However, since key_sz is of type u8, its maximum value is inherently 255, making this check redundant. This is not only limited by this kernel code, the virtio-net spec defines this. Moreover, if NETDEV_RSS_KEY_LEN is ever reduced to a value smaller than 256 in the future, this check would no longer enforce the intended limit correctly. Moreover, you should add a cover letter. Thanks. > } > > return 0; > -- > 2.25.1 >