KASSERTMSG(9): New kernel assertion with message

KASSERT() is annoying as it only prints the expression as a string.  If you
(developers) want to know a little more information, you have to do:

	#ifdef DIAGNOSTIC
		if (bad)
			panic(...);
	#endif

KASSERTMSG() replaces it into a single line:

		KASSERTMSG(!bad, ...);

Taken from NetBSD.

(There is a concern that KASSERT() messages are too long; consume more memory,
and not friendly for small monitors.  This have to be considered & revisited
later.)

"Like" from henning@
Man page review & advices from jmc@ and schwarze@

1 files changed, 5 insertions, 13 deletions

diff --git a/sys/kern/kern_physio.c b/sys/kern/kern_physio.c
index 60d44331d28..bf588f26ba9 100644
--- a/sys/kern/kern_physio.c
+++ b/sys/kern/kern_physio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_physio.c,v 1.39 2011/07/18 02:49:20 matthew Exp $	*/
+/*	$OpenBSD: kern_physio.c,v 1.40 2014/07/13 23:49:40 uebayasi Exp $	*/
 /*	$NetBSD: kern_physio.c,v 1.28 1997/05/19 10:43:28 pk Exp $	*/
 
 /*-
@@ -128,12 +128,8 @@ physio(void (*strategy)(struct buf *), dev_t dev, int flags,
 			 */
 			(*minphys)(bp);
 			todo = bp->b_bcount;
-#ifdef DIAGNOSTIC
-			if (todo < 0)
-				panic("todo < 0; minphys broken");
-			if (todo > MAXPHYS)
-				panic("todo > MAXPHYS; minphys broken");
-#endif
+			KASSERTMSG(todo >= 0, "minphys broken");
+			KASSERTMSG(todo <= MAXPHYS, "minphys broken");
 
 			/*
 			 * [lock the part of the user address space involved
@@ -194,12 +190,8 @@ physio(void (*strategy)(struct buf *), dev_t dev, int flags,
 			 *    of data to transfer]
 			 */
 			done = bp->b_bcount - bp->b_resid;
-#ifdef DIAGNOSTIC
-			if (done < 0)
-				panic("done < 0; strategy broken");
-			if (done > todo)
-				panic("done > todo; strategy broken");
-#endif
+			KASSERTMSG(done >= 0, "strategy broken");
+			KASSERTMSG(done <= todo, "strategy broken");
 			iovp->iov_len -= done;
 			iovp->iov_base = (caddr_t)iovp->iov_base + done;
 			uio->uio_offset += done;