- bump __FreeBSD version to reflect added buf_ring, memory barriers,

  and ifnet functions

- add memory barriers to <machine/atomic.h>
- update drivers to only conditionally define their own

- add lockless producer / consumer ring buffer
- remove ring buffer implementation from cxgb and update its callers

- add if_transmit(struct ifnet *ifp, struct mbuf *m) to ifnet to
  allow drivers to efficiently manage multiple hardware queues
  (i.e. not serialize all packets through one ifq)
- expose if_qflush to allow drivers to flush any driver managed queues

This work was supported by Bitgravity Inc. and Chelsio Inc.

1 files changed, 68 insertions, 0 deletions

diff --git a/sys/kern/subr_bufring.c b/sys/kern/subr_bufring.c
new file mode 100644
index 0000000..63938ea
--- /dev/null
+++ b/sys/kern/subr_bufring.c
@@ -0,0 +1,68 @@
+/**************************************************************************
+ *
+ * Copyright (c) 2007,2008 Kip Macy kmacy@freebsd.org
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. The name of Kip Macy nor the names of other
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ ***************************************************************************/
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/ktr.h>
+#include <sys/buf_ring.h>
+
+
+struct buf_ring *
+buf_ring_alloc(int count, struct malloc_type *type, int flags, struct mtx *lock)
+{
+	struct buf_ring *br;
+
+	KASSERT(powerof2(count), ("buf ring must be size power of 2"));
+	
+	br = malloc(sizeof(struct buf_ring) + count*sizeof(caddr_t),
+	    type, flags|M_ZERO);
+	if (br == NULL)
+		return (NULL);
+#ifdef DEBUG_BUFRING
+	br->br_lock = lock;
+#endif	
+	br->br_prod_size = br->br_cons_size = count;
+	br->br_prod_mask = br->br_cons_mask = count-1;
+	br->br_prod_head = br->br_cons_head = 0;
+	br->br_prod_tail = br->br_cons_tail = 0;
+		
+	return (br);
+}
+
+void
+buf_ring_free(struct buf_ring *br, struct malloc_type *type)
+{
+	free(br, type);
+}