Documentation/aoe/todo.txt

   1 There is a potential for deadlock when allocating a struct sk_buff for
   2 data that needs to be written out to aoe storage.  If the data is
   3 being written from a dirty page in order to free that page, and if
   4 there are no other pages available, then deadlock may occur when a
   5 free page is needed for the sk_buff allocation.  This situation has
   6 not been observed, but it would be nice to eliminate any potential for
   7 deadlock under memory pressure.
   8
   9 Because ATA over Ethernet is not fragmented by the kernel's IP code,
  10 the destructor member of the struct sk_buff is available to the aoe
  11 driver.  By using a mempool for allocating all but the first few
  12 sk_buffs, and by registering a destructor, we should be able to
  13 efficiently allocate sk_buffs without introducing any potential for
  14 deadlock.