From NetBSD:

Add an M_READONLY() macro, which evaluates to true if the mbuf's
data area is not to be written to.  This is the case for mbufs with
external storage which is either a non-cluster or a cluster referenced
by multiple mbufs.

Change M_LEADINGSPACE() and M_TRAILINGSPACE() to use M_READONLY(),
rather than their own testing for M_EXT.  Previously, M_LEADINGSPACE()
treated all M_EXT mbufs as read-only (which causes an extra mbuf to
be needlessly allocated when sending large TCP packets), and
M_TRAILINGSPACE() previously did not treat any external storage as
read-only (could lead to data corruption of external storage buffers!).

0 files changed, 0 insertions, 0 deletions