[src/netbsd-1-5]: src/sys/uvm Pull up rev. 1.24:

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

details:   https://anonhg.NetBSD.org/src/rev/1351fa9f1ae3
branches:  netbsd-1-5
changeset: 488251:1351fa9f1ae3
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat Jun 24 23:49:43 2000 +0000

description:
Pull up rev. 1.24:
uvm_detach: eliminate degenerate loop construction.

diffstat:

 sys/uvm/uvm_device.c |  80 +++++++++++++++++++++++----------------------------
 1 files changed, 36 insertions(+), 44 deletions(-)

diffs (103 lines):

diff -r b2460500cbde -r 1351fa9f1ae3 sys/uvm/uvm_device.c
--- a/sys/uvm/uvm_device.c      Sat Jun 24 23:47:49 2000 +0000
+++ b/sys/uvm/uvm_device.c      Sat Jun 24 23:49:43 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_device.c,v 1.22.2.1 2000/06/24 23:47:49 thorpej Exp $      */
+/*     $NetBSD: uvm_device.c,v 1.22.2.2 2000/06/24 23:49:43 thorpej Exp $      */
 
 /*
  *
@@ -318,58 +318,50 @@
        struct uvm_device *udv = (struct uvm_device *) uobj;
        UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist);
 
+
        /*
         * loop until done
         */
-
-       while (1) {
-               simple_lock(&uobj->vmobjlock);
-               
-               if (uobj->uo_refs > 1) {
-                       uobj->uo_refs--;                        /* drop ref! */
-                       simple_unlock(&uobj->vmobjlock);
-                       UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 
-                                 uobj,uobj->uo_refs,0,0);
-                       return;
-               }
+again:
+       simple_lock(&uobj->vmobjlock);
+       
+       if (uobj->uo_refs > 1) {
+               uobj->uo_refs--;                        /* drop ref! */
+               simple_unlock(&uobj->vmobjlock);
+               UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 
+                         uobj,uobj->uo_refs,0,0);
+               return;
+       }
 
 #ifdef DIAGNOSTIC
-               if (uobj->uo_npages || uobj->memq.tqh_first)
-                       panic("udv_detach: pages in a device object?");
+       if (uobj->uo_npages || !TAILQ_EMPTY(&uobj->memq))
+               panic("udv_detach: pages in a device object?");
 #endif
 
-               /*
-                * now lock udv_lock
-                */
-               simple_lock(&udv_lock);
-
-               /*
-                * is it being held?   if so, wait until others are done.
-                */
-               if (udv->u_flags & UVM_DEVICE_HOLD) {
+       /*
+        * now lock udv_lock
+        */
+       simple_lock(&udv_lock);
 
-                       /*
-                        * want it
-                        */
-                       udv->u_flags |= UVM_DEVICE_WANTED;
-                       simple_unlock(&uobj->vmobjlock);
-                       UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0);
-                       continue;
-               }
+       /*
+        * is it being held?   if so, wait until others are done.
+        */
+       if (udv->u_flags & UVM_DEVICE_HOLD) {
+               udv->u_flags |= UVM_DEVICE_WANTED;
+               simple_unlock(&uobj->vmobjlock);
+               UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0);
+               goto again;
+       }
 
-               /*
-                * got it!   nuke it now.
-                */
-
-               LIST_REMOVE(udv, u_list);
-               simple_unlock(&udv_lock);
-               if (udv->u_flags & UVM_DEVICE_WANTED)
-                       wakeup(udv);
-               simple_unlock(&uobj->vmobjlock);
-               FREE(udv, M_TEMP);
-               break;  /* DONE! */
-
-       }       /* while (1) loop */
+       /*
+        * got it!   nuke it now.
+        */
+       LIST_REMOVE(udv, u_list);
+       if (udv->u_flags & UVM_DEVICE_WANTED)
+               wakeup(udv);
+       simple_unlock(&udv_lock);
+       simple_unlock(&uobj->vmobjlock);
+       FREE(udv, M_TEMP);
 
        UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0);
        return;