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authorJoel Sherrill <joel.sherrill@OARcorp.com>2004-10-15 21:05:07 +0000
committerJoel Sherrill <joel.sherrill@OARcorp.com>2004-10-15 21:05:07 +0000
commit626ace47dfdfd510ee8363381a97339f99303959 (patch)
tree20ef46bf72c4e67a8ba0c7b59254feb995ed35bc /cpukit
parentba1a188c9baf899782523b857463671736451440 (diff)
downloadrtems-626ace47dfdfd510ee8363381a97339f99303959.tar.bz2
2004-10-15 Joel Sherrill <joel@OARcorp.com>
PR 692/rtems * rtems/src/regiongetsegment.c, rtems/src/regionreturnsegment.c: The Region Manager did not follow the proper protocol when blocking and unblocking tasks waiting on buffers. This was a bug introduced with the transition to an Allocation Mutex.
Diffstat (limited to 'cpukit')
-rw-r--r--cpukit/ChangeLog8
-rw-r--r--cpukit/rtems/src/regiongetsegment.c11
-rw-r--r--cpukit/rtems/src/regionreturnsegment.c15
3 files changed, 32 insertions, 2 deletions
diff --git a/cpukit/ChangeLog b/cpukit/ChangeLog
index 76e04cda0f..c1cc5bf052 100644
--- a/cpukit/ChangeLog
+++ b/cpukit/ChangeLog
@@ -1,3 +1,11 @@
+2004-10-15 Joel Sherrill <joel@OARcorp.com>
+
+ PR 692/rtems
+ * rtems/src/regiongetsegment.c, rtems/src/regionreturnsegment.c: The
+ Region Manager did not follow the proper protocol when blocking and
+ unblocking tasks waiting on buffers. This was a bug introduced with
+ the transition to an Allocation Mutex.
+
2004-09-29 Joel Sherrill <joel@OARcorp.com>
* configure.ac, libmisc/cpuuse/README, libmisc/stackchk/README,
diff --git a/cpukit/rtems/src/regiongetsegment.c b/cpukit/rtems/src/regiongetsegment.c
index 27d6bf66dd..dc58a27ff3 100644
--- a/cpukit/rtems/src/regiongetsegment.c
+++ b/cpukit/rtems/src/regiongetsegment.c
@@ -98,6 +98,14 @@ rtems_status_code rtems_region_get_segment(
return RTEMS_UNSATISFIED;
}
+ /*
+ * Switch from using the memory allocation mutex to using a
+ * dispatching disabled critical section. We have to do this
+ * because this thread is going to block.
+ */
+ _Thread_Disable_dispatch();
+ _RTEMS_Unlock_allocator();
+
executing->Wait.queue = &the_region->Wait_queue;
executing->Wait.id = id;
executing->Wait.count = size;
@@ -107,7 +115,8 @@ rtems_status_code rtems_region_get_segment(
_Thread_queue_Enqueue( &the_region->Wait_queue, timeout );
- _RTEMS_Unlock_allocator();
+ _Thread_Enable_dispatch();
+
return (rtems_status_code) executing->Wait.return_code;
}
diff --git a/cpukit/rtems/src/regionreturnsegment.c b/cpukit/rtems/src/regionreturnsegment.c
index 74517c0812..79d33b3828 100644
--- a/cpukit/rtems/src/regionreturnsegment.c
+++ b/cpukit/rtems/src/regionreturnsegment.c
@@ -94,6 +94,19 @@ rtems_status_code rtems_region_return_segment(
}
the_region->number_of_used_blocks -= 1;
+
+ /*
+ * Switch from using the memory allocation mutex to using a
+ * dispatching disabled critical section. We have to do this
+ * because this thread may unblock one or more threads that were
+ * waiting on memory.
+ *
+ * NOTE: The following loop is O(n) where n is the number of
+ * threads whose memory request is satisfied.
+ */
+ _RTEMS_Unlock_allocator();
+ _Thread_Disable_dispatch();
+
for ( ; ; ) {
the_thread = _Thread_queue_First( &the_region->Wait_queue );
@@ -113,8 +126,8 @@ rtems_status_code rtems_region_return_segment(
_Thread_queue_Extract( &the_region->Wait_queue, the_thread );
the_thread->Wait.return_code = RTEMS_SUCCESSFUL;
}
+ _Thread_Enable_dispatch();
- _RTEMS_Unlock_allocator();
return RTEMS_SUCCESSFUL;
}