• Paul Durrant's avatar
    xen-netback: fix guest-receive-side array sizes · ac3d5ac2
    Paul Durrant authored
    
    
    The sizes chosen for the metadata and grant_copy_op arrays on the guest
    receive size are wrong;
    
    - The meta array is needlessly twice the ring size, when we only ever
      consume a single array element per RX ring slot
    - The grant_copy_op array is way too small. It's sized based on a bogus
      assumption: that at most two copy ops will be used per ring slot. This
      may have been true at some point in the past but it's clear from looking
      at start_new_rx_buffer() that a new ring slot is only consumed if a frag
      would overflow the current slot (plus some other conditions) so the actual
      limit is MAX_SKB_FRAGS grant_copy_ops per ring slot.
    
    This patch fixes those two sizing issues and, because grant_copy_ops grows
    so much, it pulls it out into a separate chunk of vmalloc()ed memory.
    Signed-off-by: default avatarPaul Durrant <paul.durrant@citrix.com>
    Acked-by: default avatarWei Liu <wei.liu2@citrix.com>
    Cc: Ian Campbell <ian.campbell@citrix.com>
    Cc: David Vrabel <david.vrabel@citrix.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    ac3d5ac2