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/kern/subr_diskmbr.c b/sys/kern/subr_diskmbr.c
index c16f5d7346bb..9802d9f5aee5 100644
--- a/sys/kern/subr_diskmbr.c
+++ b/sys/kern/subr_diskmbr.c
@@ -187,7 +187,7 @@ reread_mbr:
 	bp->b_dev = dkmodpart(dkmodslice(dev, WHOLE_DISK_SLICE), RAW_PART);
 	bp->b_blkno = mbr_offset;
 	bp->b_bcount = lp->d_secsize;
-	bp->b_flags |= B_READ;
+	bp->b_iocmd = BIO_READ;
 	BUF_STRATEGY(bp, 1);
 	if (biowait(bp) != 0) {
 		diskerr(bp, "reading primary partition table: error",
@@ -403,7 +403,7 @@ mbr_extended(dev, lp, ssp, ext_offset, ext_size, base_ext_offset, nsectors,
 	bp->b_dev = dev;
 	bp->b_blkno = ext_offset;
 	bp->b_bcount = lp->d_secsize;
-	bp->b_flags |= B_READ;
+	bp->b_iocmd = BIO_READ;
 	BUF_STRATEGY(bp, 1);
 	if (biowait(bp) != 0) {
 		diskerr(bp, "reading extended partition table: error",