[src/trunk]: src/sys/arch/sparc64/dev Avoid use of iommu_dvmamap_unload in er...

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

details:   https://anonhg.NetBSD.org/src/rev/e1392abf079d
branches:  trunk
changeset: 749755:e1392abf079d
user:      nakayama <nakayama%NetBSD.org@localhost>
date:      Mon Dec 07 11:14:27 2009 +0000

description:
Avoid use of iommu_dvmamap_unload in error path.  It is too
expensive since it contains data cache flushing.

Some driver (tlp(4) with DM9201 on Netra X1) can only handle one
DMA segment, so it was called frequently.

diffstat:

 sys/arch/sparc64/dev/iommu.c |  45 ++++++++++++++++++++++++-------------------
 1 files changed, 25 insertions(+), 20 deletions(-)

diffs (131 lines):

diff -r 80e410aa9a77 -r e1392abf079d sys/arch/sparc64/dev/iommu.c
--- a/sys/arch/sparc64/dev/iommu.c      Mon Dec 07 10:03:37 2009 +0000
+++ b/sys/arch/sparc64/dev/iommu.c      Mon Dec 07 11:14:27 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: iommu.c,v 1.91 2009/12/06 13:39:22 nakayama Exp $      */
+/*     $NetBSD: iommu.c,v 1.92 2009/12/07 11:14:27 nakayama Exp $      */
 
 /*
  * Copyright (c) 1999, 2000 Matthew R. Green
@@ -59,7 +59,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: iommu.c,v 1.91 2009/12/06 13:39:22 nakayama Exp $");
+__KERNEL_RCSID(0, "$NetBSD: iommu.c,v 1.92 2009/12/07 11:14:27 nakayama Exp $");
 
 #include "opt_ddb.h"
 
@@ -727,9 +727,10 @@
 
        bmask = ~(boundary - 1);
        if ((pglist = segs[0]._ds_mlist) == NULL) {
-               u_long prev_va = 0UL;
+               u_long prev_va = 0UL, last_va = dvmaddr;
                paddr_t prev_pa = 0;
                int end = 0, offset;
+               bus_size_t len = size;
 
                /*
                 * This segs is made up of individual physical
@@ -737,8 +738,6 @@
                 * _bus_dmamap_load_mbuf().  Ignore the mlist and
                 * load each one individually.
                 */
-               map->dm_mapsize = size;
-
                j = 0;
                needsflush = 0;
                for (i = 0; i < nsegs ; i++) {
@@ -747,7 +746,7 @@
                        offset = (pa & PGOFSET);
                        pa = trunc_page(pa);
                        dvmaddr = trunc_page(dvmaddr);
-                       left = min(size, segs[i].ds_len);
+                       left = min(len, segs[i].ds_len);
 
                        DPRINTF(IDB_INFO, ("iommu_dvmamap_load_raw: converting "
                                "physseg %d start %lx size %lx\n", i,
@@ -773,8 +772,9 @@
                                        (long)map->dm_segs[j].ds_len));
                        } else {
                                if (j >= map->_dm_segcnt) {
-                                       iommu_dvmamap_unload(t, map);
-                                       return (EFBIG);
+                                       iommu_remove(is, map->_dm_dvmastart,
+                                           last_va - map->_dm_dvmastart);
+                                       goto fail;
                                }
                                map->dm_segs[j].ds_addr = sgstart;
                                map->dm_segs[j].ds_len = left;
@@ -795,8 +795,9 @@
                                        (long)map->dm_segs[j].ds_addr,
                                        (long)map->dm_segs[j].ds_len));
                                if (++j >= map->_dm_segcnt) {
-                                       iommu_dvmamap_unload(t, map);
-                                       return (EFBIG);
+                                       iommu_remove(is, map->_dm_dvmastart,
+                                           last_va - map->_dm_dvmastart);
+                                       goto fail;
                                }
                                sgstart = roundup(sgstart, boundary);
                                map->dm_segs[j].ds_addr = sgstart;
@@ -822,14 +823,16 @@
                                }
                                dvmaddr += pagesz;
                                pa += pagesz;
+                               last_va = dvmaddr;
                        }
 
-                       size -= left;
+                       len -= left;
                        ++j;
                }
                if (needsflush)
                        iommu_strbuf_flush_done(sb);
 
+               map->dm_mapsize = size;
                map->dm_nsegs = j;
 #ifdef DIAGNOSTIC
                { int seg;
@@ -853,7 +856,6 @@
         * This was allocated with bus_dmamem_alloc.
         * The pages are on a `pglist'.
         */
-       map->dm_mapsize = size;
        i = 0;
        sgstart = dvmaddr;
        sgend = sgstart + size - 1;
@@ -867,14 +869,7 @@
                        (long)map->dm_segs[i].ds_len));
                if (++i >= map->_dm_segcnt) {
                        /* Too many segments.  Fail the operation. */
-                       s = splhigh();
-                       /* How can this fail?  And if it does what can we do? */
-                       err = extent_free(is->is_dvmamap,
-                               dvmaddr, sgsize, EX_NOWAIT);
-                       map->_dm_dvmastart = 0;
-                       map->_dm_dvmasize = 0;
-                       splx(s);
-                       return (EFBIG);
+                       goto fail;
                }
                sgstart = roundup(sgstart, boundary);
                map->dm_segs[i].ds_addr = sgstart;
@@ -919,6 +914,16 @@
        }
 #endif
        return (0);
+
+fail:
+       s = splhigh();
+       /* How can this fail?  And if it does what can we do? */
+       err = extent_free(is->is_dvmamap, map->_dm_dvmastart, sgsize,
+           EX_NOWAIT);
+       map->_dm_dvmastart = 0;
+       map->_dm_dvmasize = 0;
+       splx(s);
+       return (EFBIG);
 }