The following reply was made to PR port-xen/33110; it has been noted by GNATS.

From: Jed Davis <jdev@panix.com>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: port-xen/33110
Date: Mon, 20 Mar 2006 21:55:21 -0500

 --gBBFr7Ir9EOA20Yy
 Content-Type: text/plain; charset=us-ascii
 Content-Disposition: inline
 
 I've attempted to fix this myself, but am not sure I've gotten it
 entirely right; diff is attached.
 
 
 --gBBFr7Ir9EOA20Yy
 Content-Type: text/plain; charset=us-ascii
 Content-Disposition: attachment; filename="xbd-3-nowait.diff"
 
 Index: arch/xen/xen/xbd.c
 ===================================================================
 RCS file: /cvsroot/src/sys/arch/xen/xen/xbd.c,v
 retrieving revision 1.14.2.5
 diff -u -p -r1.14.2.5 xbd.c
 --- arch/xen/xen/xbd.c	28 Apr 2005 10:28:42 -0000	1.14.2.5
 +++ arch/xen/xen/xbd.c	20 Mar 2006 23:22:22 -0000
 @@ -1140,7 +1140,7 @@ xbdsize(dev_t dev)
  	return dk_size(xs->sc_di, &xs->sc_dksc, dev);
  }
  
 -static void
 +static int
  map_align(struct xbdreq *xr)
  {
  	int s;
 @@ -1148,8 +1148,10 @@ map_align(struct xbdreq *xr)
  	s = splvm();
  	xr->xr_aligned = uvm_km_kmemalloc1(kmem_map, NULL,
  	    xr->xr_bqueue, XEN_BSIZE, UVM_UNKNOWN_OFFSET,
 -	    0/*  UVM_KMF_NOWAIT */);
 +	    UVM_KMF_NOWAIT);
  	splx(s);
 +	if (xr->xr_aligned == 0)
 +		return 0;
  	DPRINTF(XBDB_IO, ("map_align(%p): bp %p addr %p align 0x%08lx "
  	    "size 0x%04lx\n", xr, xr->xr_bp, xr->xr_bp->b_data,
  	    xr->xr_aligned, xr->xr_bqueue));
 @@ -1157,6 +1159,7 @@ map_align(struct xbdreq *xr)
  	if ((xr->xr_bp->b_flags & B_READ) == 0)
  		memcpy((void *)xr->xr_aligned, xr->xr_bp->b_data,
  		    xr->xr_bqueue);
 +	return 1;
  }
  
  static void
 @@ -1361,7 +1364,13 @@ xbdstart(struct dk_softc *dksc, struct b
  	pxr->xr_sc = xs;
  
  	if (pxr->xr_data & (XEN_BSIZE - 1))
 -		map_align(pxr);
 +		if (!map_align(pxr)) { /* No memory; try later. */
 +			DPRINTF(XBDB_IO, ("xbdstart: map_align failed\n"));
 +			ret = -1;
 +			disk_unbusy(&dksc->sc_dkdev, 0, bp->b_flags & B_READ);
 +			PUT_XBDREQ(pxr);
 +			goto out;
 +		}
  
  	fill_ring(pxr);
  
 
 --gBBFr7Ir9EOA20Yy--