 @@ -1,14 +1,14 @@
-/*      $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.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
 @@ -40,27 +40,27 @@
  * - initiate request: xbdread/write/open/ioctl/..
  * - depending on operation, it is handled directly by disk(9) subsystem or
  *   goes through physio(9) first.
  * - the request is ultimately processed by xbd_diskstart() that prepares the
  *   xbd requests, post them in the ring I/O queue, then signal the backend.
+ *
  * When a response is available in the queue, the backend signals the frontend
  * via its event channel. This triggers xbd_handler(), which will link back
  * the response to its request through the request ID, and mark the I/O as
  * completed.
  */
 #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"
 #include <sys/param.h>
 #include <sys/buf.h>
 #include <sys/bufq.h>
 #include <sys/device.h>
 #include <sys/disk.h>
 #include <sys/disklabel.h>
 #include <sys/conf.h>
 #include <sys/fcntl.h>
 #include <sys/kernel.h>
 @@ -735,53 +735,59 @@ again:
 			xbdreq->req_sync.s_done = 1;
 			cv_broadcast(&sc->sc_cache_flush_cv);
 			/* caller will free the req */
 			continue;
+		}
 		if (rep->operation != BLKIF_OP_READ &&
 		    rep->operation != BLKIF_OP_WRITE) {
 			aprint_error_dev(sc->sc_dksc.sc_dev,
 			    "bad operation %d from backend\n", rep->operation);
 			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
 			 * expect the backend to release the grant
 			 * immediately.
 			 */
 			KASSERT(xengnt_status(xbdreq->req_gntref[seg]) == 0);
 			xengnt_revoke_access(xbdreq->req_gntref[seg]);
+		}
 		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);
+	}
 	xen_rmb();
 	sc->sc_ring.rsp_cons = i;
 	RING_FINAL_CHECK_FOR_RESPONSES(&sc->sc_ring, more_to_do);
 	if (more_to_do)
 		goto again;
 	cv_signal(&sc->sc_req_cv);
 @@ -1057,27 +1063,27 @@ xbd_diskstart(device_t self, struct buf
 		error = EINVAL;
 		goto out;
+	}
 	/* We are now committed to the transfer */
 	SLIST_REMOVE_HEAD(&sc->sc_xbdreq_head, req_next);
 	req = RING_GET_REQUEST(&sc->sc_ring, sc->sc_ring.req_prod_pvt);
 	req->id = xbdreq->req_id;
 	req->operation =
 	    bp->b_flags & B_READ ? BLKIF_OP_READ : BLKIF_OP_WRITE;
 	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];
 		ma = dmaseg->ds_addr;
 		off = ma & PAGE_MASK;
 		nbytes = dmaseg->ds_len;
 		nsects = nbytes >> XEN_BSHIFT;
 		req->seg[seg].first_sect = off >> XEN_BSHIFT;
 		req->seg[seg].last_sect = (off >> XEN_BSHIFT) + nsects - 1;
 		KASSERT(req->seg[seg].first_sect <= req->seg[seg].last_sect);
 		KASSERT(req->seg[seg].last_sect < (PAGE_SIZE / XEN_BSIZE));