Remove B_READ, B_WRITE and B_FREEBUF and replace them with a new

field in struct buf: b_iocmd.  The b_iocmd is enforced to have
exactly one bit set.

B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.

Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.

Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue.  It is likely to write on your disk
where it should have been reading.

This change is a step in the direction towards a stackable BIO capability.

A lot of this patch were machine generated (Thanks to style(9) compliance!)

Vinum users:  Greg has not had time to test this yet, be careful.

1 files changed, 2 insertions, 2 deletions

diff --git a/sys/vm/vnode_pager.c b/sys/vm/vnode_pager.c
index 1ccc692..279f47c 100644
--- a/sys/vm/vnode_pager.c
+++ b/sys/vm/vnode_pager.c
@@ -411,7 +411,7 @@ vnode_pager_input_smlfs(object, m)
 			bp = getpbuf(&vnode_pbuf_freecnt);
 
 			/* build a minimal buffer header */
-			bp->b_flags = B_READ | B_CALL;
+			bp->b_iocmd = BIO_READ;
 			bp->b_iodone = vnode_pager_iodone;
 			bp->b_rcred = bp->b_wcred = curproc->p_ucred;
 			if (bp->b_rcred != NOCRED)
@@ -729,7 +729,7 @@ vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
 	pmap_qenter(kva, m, count);
 
 	/* build a minimal buffer header */
-	bp->b_flags = B_READ | B_CALL;
+	bp->b_iocmd = BIO_READ;
 	bp->b_iodone = vnode_pager_iodone;
 	/* B_PHYS is not set, but it is nice to fill this in */
 	bp->b_rcred = bp->b_wcred = curproc->p_ucred;