Xen netback driver rewrite.

share/man/man4/Makefile,
share/man/man4/xnb.4,
sys/dev/xen/netback/netback.c,
sys/dev/xen/netback/netback_unit_tests.c:

	Rewrote the netback driver for xen to attach properly via newbus
	and work properly in both HVM and PVM mode (only HVM is tested).
	Works with the in-tree FreeBSD netfront driver or the Windows
	netfront driver from SuSE.  Has not been extensively tested with
	a Linux netfront driver.  Does not implement LRO, TSO, or
	polling.  Includes unit tests that may be run through sysctl
	after compiling with XNB_DEBUG defined.

sys/dev/xen/blkback/blkback.c,
sys/xen/interface/io/netif.h:

	Comment elaboration.

sys/kern/uipc_mbuf.c:

	Fix page fault in kernel mode when calling m_print() on a
	null mbuf.  Since m_print() is only used for debugging, there
	are no performance concerns for extra error checking code.

sys/kern/subr_scanf.c:

	Add the "hh" and "ll" width specifiers from C99 to scanf().
	A few callers were already using "ll" even though scanf()
	was handling it as "l".

Submitted by:	Alan Somers <alans@spectralogic.com>
Submitted by:	John Suykerbuyk <johns@spectralogic.com>
Sponsored by:	Spectra Logic
MFC after:	1 week
Reviewed by:	ken

1 files changed, 5 insertions, 3 deletions

diff --git a/sys/xen/interface/io/netif.h b/sys/xen/interface/io/netif.h
index fbb5c27..261b7d9 100644
--- a/sys/xen/interface/io/netif.h
+++ b/sys/xen/interface/io/netif.h
@@ -42,7 +42,7 @@
  * This is the 'wire' format for packets:
  *  Request 1: netif_tx_request -- NETTXF_* (any flags)
  * [Request 2: netif_tx_extra]  (only if request 1 has NETTXF_extra_info)
- * [Request 3: netif_tx_extra]  (only if request 2 has XEN_NETIF_EXTRA_MORE)
+ * [Request 3: netif_tx_extra] (only if request 2 has XEN_NETIF_EXTRA_FLAG_MORE)
  *  Request 4: netif_tx_request -- NETTXF_more_data
  *  Request 5: netif_tx_request -- NETTXF_more_data
  *  ...
@@ -70,7 +70,9 @@ struct netif_tx_request {
     uint16_t offset;       /* Offset within buffer page */
     uint16_t flags;        /* NETTXF_* */
     uint16_t id;           /* Echoed in response message. */
-    uint16_t size;         /* Packet size in bytes.       */
+    uint16_t size;         /* For the first request in a packet, the packet 
+			      size in bytes.  For subsequent requests, the 
+			      size of that request's associated data in bytes*/
 };
 typedef struct netif_tx_request netif_tx_request_t;
 
@@ -175,7 +177,7 @@ struct netif_rx_response {
     uint16_t id;
     uint16_t offset;       /* Offset in page of start of received packet  */
     uint16_t flags;        /* NETRXF_* */
-    int16_t  status;       /* -ve: BLKIF_RSP_* ; +ve: Rx'ed pkt size. */
+    int16_t  status;       /* -ve: NETIF_RSP_* ; +ve: Rx'ed response size. */
 };
 typedef struct netif_rx_response netif_rx_response_t;