[src/trunk]: src/sys/arch/xen/xen change xbd_unmap_align() to get the bp via ...

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

details:   https://anonhg.NetBSD.org/src/rev/64ef7d334baa
branches:  trunk
changeset: 1011856:64ef7d334baa
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Mon Jul 13 21:21:56 2020 +0000

description:
change xbd_unmap_align() to get the bp via argument rathen than
req_bp, to avoid using req_bp after it's been set to NULL by the
time xbd_unmap_align() is called in xbd_handler(); this fixes
regression caused by previous fix

also make sure xbd_unmap_align() works correctly even when using the
linked request pair for I/O (ie. for Dom0 not supporting indirect
segments), regardless of the order the paired requests finish

diffstat:

 sys/arch/xen/xen/xbd_xenbus.c |  29 +++++++++++++++--------------
 1 files changed, 15 insertions(+), 14 deletions(-)

diffs (99 lines):

diff -r c84d18e958e1 -r 64ef7d334baa sys/arch/xen/xen/xbd_xenbus.c
--- a/sys/arch/xen/xen/xbd_xenbus.c     Mon Jul 13 16:54:03 2020 +0000
+++ b/sys/arch/xen/xen/xbd_xenbus.c     Mon Jul 13 21:21:56 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xbd_xenbus.c,v 1.128 2020/06/29 21:45:50 jdolecek Exp $      */
+/*      $NetBSD: xbd_xenbus.c,v 1.129 2020/07/13 21:21:56 jdolecek Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -50,7 +50,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.128 2020/06/29 21:45:50 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.129 2020/07/13 21:21:56 jdolecek Exp $");
 
 #include "opt_xen.h"
 
@@ -157,7 +157,7 @@
        SLIST_HEAD(,xbd_indirect) sc_indirect_head;
 
        vmem_addr_t sc_unalign_buffer;
-       struct xbd_req *sc_unalign_used;
+       void *sc_unalign_used;
 
        int sc_backend_status; /* our status with backend */
 #define BLKIF_STATE_DISCONNECTED 0
@@ -206,7 +206,8 @@
 static void xbd_diskstart_submit_indirect(struct xbd_xenbus_softc *,
        struct xbd_req *, struct buf *bp);
 static int  xbd_map_align(struct xbd_xenbus_softc *, struct xbd_req *);
-static void xbd_unmap_align(struct xbd_xenbus_softc *, struct xbd_req *, bool);
+static void xbd_unmap_align(struct xbd_xenbus_softc *, struct xbd_req *,
+       struct buf *);
 
 static void xbdminphys(struct buf *);
 
@@ -887,7 +888,7 @@
                bus_dmamap_unload(sc->sc_xbusd->xbusd_dmat, xbdreq->req_dmamap);
 
                if (__predict_false(bp->b_data != xbdreq->req_data))
-                       xbd_unmap_align(sc, xbdreq, true);
+                       xbd_unmap_align(sc, xbdreq, bp);
                xbdreq->req_data = NULL;
 
                dk_done(&sc->sc_dksc, bp);
@@ -1187,7 +1188,7 @@
                printf("%s: %s: bus_dmamap_load failed\n",
                    device_xname(sc->sc_dksc.sc_dev), __func__);
                if (__predict_false(bp->b_data != xbdreq->req_data))
-                       xbd_unmap_align(sc, xbdreq, false);
+                       xbd_unmap_align(sc, xbdreq, NULL);
                error = EINVAL;
                goto out;
        }
@@ -1213,7 +1214,7 @@
                        bus_dmamap_unload(sc->sc_xbusd->xbusd_dmat,
                            xbdreq->req_dmamap);
                        if (__predict_false(bp->b_data != xbdreq->req_data))
-                               xbd_unmap_align(sc, xbdreq, false);
+                               xbd_unmap_align(sc, xbdreq, NULL);
                        error = EAGAIN;
                        goto out;
                }
@@ -1243,7 +1244,7 @@
                xbdreq->req_parent_done = false;
                xbdreq2->req_parent = xbdreq;
                xbdreq2->req_bp = bp;
-               xbdreq2->req_data = NULL;
+               xbdreq2->req_data = xbdreq->req_data;
                xbd_diskstart_submit(sc, xbdreq2->req_id,
                    bp, XBD_MAX_CHUNK, xbdreq->req_dmamap,
                    xbdreq->req_gntref);
@@ -1379,7 +1380,7 @@
                sc->sc_cnt_unalign_busy.ev_count++;
                return EAGAIN;
        }
-       sc->sc_unalign_used = req;
+       sc->sc_unalign_used = req->req_bp;
 
        KASSERT(req->req_bp->b_bcount <= MAXPHYS);
        req->req_data = (void *)sc->sc_unalign_buffer;
@@ -1390,11 +1391,11 @@
 }
 
 static void
-xbd_unmap_align(struct xbd_xenbus_softc *sc, struct xbd_req *req, bool sync)
+xbd_unmap_align(struct xbd_xenbus_softc *sc, struct xbd_req *req,
+    struct buf *bp)
 {
-       KASSERT(sc->sc_unalign_used == req);
-       if (sync && req->req_bp->b_flags & B_READ)
-               memcpy(req->req_bp->b_data, req->req_data,
-                   req->req_bp->b_bcount);
+       KASSERT(!bp || sc->sc_unalign_used == bp);
+       if (bp && bp->b_flags & B_READ)
+               memcpy(bp->b_data, req->req_data, bp->b_bcount);
        sc->sc_unalign_used = NULL;
 }