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

2 files changed, 23 insertions, 3 deletions

diff --git a/sys/kern/subr_scanf.c b/sys/kern/subr_scanf.c
index 0814953..824e392 100644
--- a/sys/kern/subr_scanf.c
+++ b/sys/kern/subr_scanf.c
@@ -59,6 +59,7 @@ __FBSDID("$FreeBSD$");
 #define	POINTER		0x10	/* weird %p pointer (`fake hex') */
 #define	NOSKIP		0x20	/* do not skip blanks */
 #define	QUAD		0x400
+#define	SHORTSHORT	0x4000	/** hh: char */
 
 /*
  * The following are used in numeric conversions only:
@@ -160,13 +161,23 @@ literal:
 			flags |= SUPPRESS;
 			goto again;
 		case 'l':
-			flags |= LONG;
+			if (flags & LONG){
+				flags &= ~LONG;
+				flags |= QUAD;
+			} else {
+				flags |= LONG;
+			}
 			goto again;
 		case 'q':
 			flags |= QUAD;
 			goto again;
 		case 'h':
-			flags |= SHORT;
+			if (flags & SHORT){
+				flags &= ~SHORT;
+				flags |= SHORTSHORT;
+			} else {
+				flags |= SHORT;
+			}
 			goto again;
 
 		case '0': case '1': case '2': case '3': case '4':
@@ -235,7 +246,9 @@ literal:
 			nconversions++;
 			if (flags & SUPPRESS)	/* ??? */
 				continue;
-			if (flags & SHORT)
+			if (flags & SHORTSHORT)
+				*va_arg(ap, char *) = nread;
+			else if (flags & SHORT)
 				*va_arg(ap, short *) = nread;
 			else if (flags & LONG)
 				*va_arg(ap, long *) = nread;
@@ -510,6 +523,8 @@ literal:
 				if (flags & POINTER)
 					*va_arg(ap, void **) =
 						(void *)(uintptr_t)res;
+				else if (flags & SHORTSHORT)
+					*va_arg(ap, char *) = res;
 				else if (flags & SHORT)
 					*va_arg(ap, short *) = res;
 				else if (flags & LONG)
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index 871132c..620246b 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1410,6 +1410,11 @@ m_print(const struct mbuf *m, int maxlen)
 	int pdata;
 	const struct mbuf *m2;
 
+	if (m == NULL) {
+		printf("mbuf: %p\n", m);
+		return;
+	}
+
 	if (m->m_flags & M_PKTHDR)
 		len = m->m_pkthdr.len;
 	else