b.a.t.m.a.n.lists.open-mesh.org archive mirror
 help / color / mirror / Atom feed
From: <gregkh@linuxfoundation.org>
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
Subject: Patch "batman-adv: Don't always reallocate the fragmentation skb head" has been added to the 4.19-stable tree
Date: Tue, 23 Nov 2021 13:35:01 +0100	[thread overview]
Message-ID: <16376709011227@kroah.com> (raw)
In-Reply-To: <20211120124044.261086-5-sven@narfation.org>

This is a note to let you know that I've just added the patch titled

    batman-adv: Don't always reallocate the fragmentation skb head

to the 4.19-stable tree which can be found at:

The filename of the patch is:
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.

From foo@baz Tue Nov 23 01:33:57 PM CET 2021
From: Sven Eckelmann <sven@narfation.org>
Date: Sat, 20 Nov 2021 13:40:44 +0100
Subject: batman-adv: Don't always reallocate the fragmentation skb head
To: stable@vger.kernel.org
Cc: b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann <sven@narfation.org>, Simon Wunderlich <sw@simonwunderlich.de>
Message-ID: <20211120124044.261086-5-sven@narfation.org>

From: Sven Eckelmann <sven@narfation.org>

commit 992b03b88e36254e26e9a4977ab948683e21bd9f upstream.

When a packet is fragmented by batman-adv, the original batman-adv header
is not modified. Only a new fragmentation is inserted between the original
one and the ethernet header. The code must therefore make sure that it has
a writable region of this size in the skbuff head.

But it is not useful to always reallocate the skbuff by this size even when
there would be more than enough headroom still in the skb. The reallocation
is just to costly during in this codepath.

Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 net/batman-adv/fragmentation.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -539,13 +539,14 @@ int batadv_frag_send_packet(struct sk_bu
-	/* Make room for the fragment header. */
-	if (batadv_skb_head_push(skb, header_size) < 0 ||
-	    pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0) {
-		ret = -ENOMEM;
+	/* make sure that there is at least enough head for the fragmentation
+	 * and ethernet headers
+	 */
+	ret = skb_cow_head(skb, ETH_HLEN + header_size);
+	if (ret < 0)
 		goto put_primary_if;
-	}
+	skb_push(skb, header_size);
 	memcpy(skb->data, &frag_header, header_size);
 	/* Send the last fragment */

Patches currently in stable-queue which might be from sven@narfation.org are


      reply	other threads:[~2021-11-23 12:35 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-20 12:40 [PATCH 4.19 0/4] batman-adv: Fixes for stable/linux-4.19.y Sven Eckelmann
2021-11-20 12:40 ` [PATCH 4.19 1/4] batman-adv: mcast: fix duplicate mcast packets in BLA backbone from LAN Sven Eckelmann
2021-11-23 12:35   ` Patch "batman-adv: mcast: fix duplicate mcast packets in BLA backbone from LAN" has been added to the 4.19-stable tree gregkh
2021-11-20 12:40 ` [PATCH 4.19 2/4] batman-adv: Consider fragmentation for needed_headroom Sven Eckelmann
2021-11-23 12:35   ` Patch "batman-adv: Consider fragmentation for needed_headroom" has been added to the 4.19-stable tree gregkh
2021-11-20 12:40 ` [PATCH 4.19 3/4] batman-adv: Reserve needed_*room for fragments Sven Eckelmann
2021-11-23 12:35   ` Patch "batman-adv: Reserve needed_*room for fragments" has been added to the 4.19-stable tree gregkh
2021-11-20 12:40 ` [PATCH 4.19 4/4] batman-adv: Don't always reallocate the fragmentation skb head Sven Eckelmann
2021-11-23 12:35   ` gregkh [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=16376709011227@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=b.a.t.m.a.n@lists.open-mesh.org \
    --cc=stable-commits@vger.kernel.org \
    --cc=sven@narfation.org \
    --cc=sw@simonwunderlich.de \


* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).