backports: backport inet_frag_maybe_warn_overflow()

This is used by the ieee802154 reassembly code. This is
a straight forward backport.

mcgrof@ergon ~/linux-next (git::master)$ git describe --contains 5a3da1fe95

commit 5a3da1fe9561828d0ca7eca664b16ec2b9bf0055
Author: Hannes Frederic Sowa <>
Date:   Fri Mar 15 11:32:30 2013 +0000

    inet: limit length of fragment queue hash table bucket lists

    This patch introduces a constant limit of the fragment queue hash
    table bucket list lengths. Currently the limit 128 is choosen somewhat
    arbitrary and just ensures that we can fill up the fragment cache with
    empty packets up to the default ip_frag_high_thresh limits. It should
    just protect from list iteration eating considerable amounts of cpu.

    If we reach the maximum length in one hash bucket a warning is printed.
    This is implemented on the caller side of inet_frag_find to distinguish
    between the different users of inet_fragment.c.

    I dropped the out of memory warning in the ipv4 fragment lookup path,
    because we already get a warning by the slab allocator.

    Cc: Eric Dumazet <>
    Cc: Jesper Dangaard Brouer <>
    Signed-off-by: Hannes Frederic Sowa <>
    Acked-by: Eric Dumazet <>
    Signed-off-by: David S. Miller <>

Cc: Hannes Frederic Sowa <>
Signed-off-by: Luis R. Rodriguez <>
2 files changed