From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Patch "batman-adv: Reserve needed_*room for fragments" has been added to the 5.4-stable tree From: Date: Tue, 23 Nov 2021 13:33:40 +0100 In-Reply-To: <20211120124053.261156-3-sven@narfation.org> Message-ID: <163767082022193@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: b.a.t.m.a.n@lists.open-mesh.org, gregkh@linuxfoundation.org, sven@narfation.org, sw@simonwunderlich.de Cc: stable-commits@vger.kernel.org This is a note to let you know that I've just added the patch titled batman-adv: Reserve needed_*room for fragments to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: batman-adv-reserve-needed_-room-for-fragments.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From foo@baz Tue Nov 23 01:32:30 PM CET 2021 From: Sven Eckelmann Date: Sat, 20 Nov 2021 13:40:52 +0100 Subject: batman-adv: Reserve needed_*room for fragments To: stable@vger.kernel.org Cc: b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann , Simon Wunderlich Message-ID: <20211120124053.261156-3-sven@narfation.org> From: Sven Eckelmann commit c5cbfc87558168ef4c3c27ce36eba6b83391db19 upstream. The batadv net_device is trying to propagate the needed_headroom and needed_tailroom from the lower devices. This is needed to avoid cost intensive reallocations using pskb_expand_head during the transmission. But the fragmentation code split the skb's without adding extra room at the end/beginning of the various fragments. This reduced the performance of transmissions over complex scenarios (batadv on vxlan on wireguard) because the lower devices had to perform the reallocations at least once. Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/fragmentation.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -391,6 +391,7 @@ out: /** * batadv_frag_create() - create a fragment from skb + * @net_dev: outgoing device for fragment * @skb: skb to create fragment from * @frag_head: header to use in new fragment * @fragment_size: size of new fragment @@ -401,22 +402,25 @@ out: * * Return: the new fragment, NULL on error. */ -static struct sk_buff *batadv_frag_create(struct sk_buff *skb, +static struct sk_buff *batadv_frag_create(struct net_device *net_dev, + struct sk_buff *skb, struct batadv_frag_packet *frag_head, unsigned int fragment_size) { + unsigned int ll_reserved = LL_RESERVED_SPACE(net_dev); + unsigned int tailroom = net_dev->needed_tailroom; struct sk_buff *skb_fragment; unsigned int header_size = sizeof(*frag_head); unsigned int mtu = fragment_size + header_size; - skb_fragment = netdev_alloc_skb(NULL, mtu + ETH_HLEN); + skb_fragment = dev_alloc_skb(ll_reserved + mtu + tailroom); if (!skb_fragment) goto err; skb_fragment->priority = skb->priority; /* Eat the last mtu-bytes of the skb */ - skb_reserve(skb_fragment, header_size + ETH_HLEN); + skb_reserve(skb_fragment, ll_reserved + header_size); skb_split(skb, skb_fragment, skb->len - fragment_size); /* Add the header */ @@ -439,11 +443,12 @@ int batadv_frag_send_packet(struct sk_bu struct batadv_orig_node *orig_node, struct batadv_neigh_node *neigh_node) { + struct net_device *net_dev = neigh_node->if_incoming->net_dev; struct batadv_priv *bat_priv; struct batadv_hard_iface *primary_if = NULL; struct batadv_frag_packet frag_header; struct sk_buff *skb_fragment; - unsigned int mtu = neigh_node->if_incoming->net_dev->mtu; + unsigned int mtu = net_dev->mtu; unsigned int header_size = sizeof(frag_header); unsigned int max_fragment_size, num_fragments; int ret; @@ -503,7 +508,7 @@ int batadv_frag_send_packet(struct sk_bu goto put_primary_if; } - skb_fragment = batadv_frag_create(skb, &frag_header, + skb_fragment = batadv_frag_create(net_dev, skb, &frag_header, max_fragment_size); if (!skb_fragment) { ret = -ENOMEM; Patches currently in stable-queue which might be from sven@narfation.org are queue-5.4/batman-adv-consider-fragmentation-for-needed_headroom.patch queue-5.4/batman-adv-reserve-needed_-room-for-fragments.patch queue-5.4/batman-adv-don-t-always-reallocate-the-fragmentation-skb-head.patch