In order to reduce use of M_EXT outside of the mbuf allocator and

socket-buffer implementations, introduce a return value for MCLGET()
(and m_cljget() that underlies it) to allow the caller to avoid testing
M_EXT itself.  Update all callers to use the return value.

With this change, very few network device drivers remain aware of
M_EXT; the primary exceptions lie in mbuf-chain pretty printers for
debugging, and in a few cases, custom mbuf and cluster allocation
implementations.

NB: This is a difficult-to-test change as it touches many drivers for
which I don't have physical devices.  Instead we've gone for intensive
review, but further post-commit review would definitely be appreciated
to spot errors where changes could not easily be made mechanically,
but were largely mechanical in nature.

Differential Revision:	https://reviews.freebsd.org/D1440
Reviewed by:	adrian, bz, gnn
Sponsored by:	EMC / Isilon Storage Division

1 files changed, 1 insertions, 4 deletions

diff --git a/sys/dev/ed/if_ed.c b/sys/dev/ed/if_ed.c
index 46524dd9d6b8..be9d274aadd6 100644
--- a/sys/dev/ed/if_ed.c
+++ b/sys/dev/ed/if_ed.c
@@ -1323,10 +1323,7 @@ ed_get_packet(struct ed_softc *sc, bus_size_t buf, u_short len)
 	 */
 	if ((len + 2) > MHLEN) {
 		/* Attach an mbuf cluster */
-		MCLGET(m, M_NOWAIT);
-
-		/* Insist on getting a cluster */
-		if ((m->m_flags & M_EXT) == 0) {
+		if (!(MCLGET(m, M_NOWAIT))) {
 			m_freem(m);
 			return;
 		}