[src/trunk]: src/sys/arch/xen/xen rearrange slightly to do proper b_resid acc...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/a07d24f3136b
branches:  trunk
changeset: 971133:a07d24f3136b
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Tue Apr 14 14:06:24 2020 +0000

description:
rearrange slightly to do proper b_resid accounting, to prepare for partial
transfers

diffstat:

 sys/arch/xen/xen/xbd_xenbus.c |  34 ++++++++++++++++++++--------------
 1 files changed, 20 insertions(+), 14 deletions(-)

diffs (73 lines):

diff -r b0708300b95c -r a07d24f3136b sys/arch/xen/xen/xbd_xenbus.c
--- a/sys/arch/xen/xen/xbd_xenbus.c     Tue Apr 14 13:58:11 2020 +0000
+++ b/sys/arch/xen/xen/xbd_xenbus.c     Tue Apr 14 14:06:24 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xbd_xenbus.c,v 1.111 2020/04/14 13:10:43 jdolecek Exp $      */
+/*      $NetBSD: xbd_xenbus.c,v 1.112 2020/04/14 14:06:24 jdolecek Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -50,7 +50,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.111 2020/04/14 13:10:43 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.112 2020/04/14 14:06:24 jdolecek Exp $");
 
 #include "opt_xen.h"
 
@@ -745,6 +745,23 @@
                        continue;
                }
 
+               bp = xbdreq->req_bp;
+               KASSERT(bp != NULL && bp->b_data != NULL);
+               DPRINTF(("%s(%p): b_bcount = %ld\n", __func__,
+                   bp, (long)bp->b_bcount));
+
+               if (rep->status != BLKIF_RSP_OKAY) {
+                       bp->b_error = EIO;
+                       bp->b_resid = bp->b_bcount;
+               } else {
+                       KASSERTMSG(xbdreq->req_dmamap->dm_mapsize <=
+                           bp->b_resid, "mapsize %d > b_resid %d",
+                           (int)xbdreq->req_dmamap->dm_mapsize,
+                           (int)bp->b_resid);
+                       bp->b_resid -= xbdreq->req_dmamap->dm_mapsize;
+                       KASSERT(bp->b_resid == 0);
+               }
+
                for (seg = 0; seg < xbdreq->req_dmamap->dm_nsegs; seg++) {
                        /*
                         * We are not allowing persistent mappings, so
@@ -757,21 +774,10 @@
 
                bus_dmamap_unload(sc->sc_xbusd->xbusd_dmat, xbdreq->req_dmamap);
 
-               bp = xbdreq->req_bp;
-               KASSERT(bp != NULL && bp->b_data != NULL);
-               DPRINTF(("%s(%p): b_bcount = %ld\n", __func__,
-                   bp, (long)bp->b_bcount));
-
                if (__predict_false(bp->b_data != xbdreq->req_data))
                        xbd_unmap_align(sc, xbdreq, true);
                xbdreq->req_bp = xbdreq->req_data = NULL;
 
-               /* b_resid was set in dk_start, only override on error */
-               if (rep->status != BLKIF_RSP_OKAY) {
-                       bp->b_error = EIO;
-                       bp->b_resid = bp->b_bcount;
-               }
-
                dk_done(&sc->sc_dksc, bp);
 
                SLIST_INSERT_HEAD(&sc->sc_xbdreq_head, xbdreq, req_next);
@@ -1067,7 +1073,7 @@
        req->sector_number = bp->b_rawblkno;
        req->handle = sc->sc_handle;
 
-       bp->b_resid = 0;
+       bp->b_resid = bp->b_bcount;
        for (seg = 0; seg < xbdreq->req_dmamap->dm_nsegs; seg++) {
                bus_dma_segment_t *dmaseg = &xbdreq->req_dmamap->dm_segs[seg];