- Fix rman_manage_region() to be a lot more intelligent. It now checks

  for overlaps, but more importantly, it collapses adjacent free regions.
  This is needed to cope with BIOSen that split up ports for system devices
  (like IPMI controllers) across multiple system resource entries.
- Now that rman_manage_region() is not so dumb, remove extra logic in the
  x86 nexus drivers to populate the IRQ rman that manually coalesced the
  regions.

MFC after:	1 week

1 files changed, 41 insertions, 3 deletions

diff --git a/sys/kern/subr_rman.c b/sys/kern/subr_rman.c
index c180eba..f59327a 100644
--- a/sys/kern/subr_rman.c
+++ b/sys/kern/subr_rman.c
@@ -155,7 +155,7 @@ rman_init(struct rman *rm)
 int
 rman_manage_region(struct rman *rm, u_long start, u_long end)
 {
-	struct resource_i *r, *s;
+	struct resource_i *r, *s, *t;
 
 	DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n",
 	    rm->rm_descr, start, end));
@@ -167,15 +167,53 @@ rman_manage_region(struct rman *rm, u_long start, u_long end)
 	r->r_rm = rm;
 
 	mtx_lock(rm->rm_mtx);
+
+	/* Skip entries before us. */
 	for (s = TAILQ_FIRST(&rm->rm_list);
-	     s && s->r_end < r->r_start;
+	     s && s->r_end + 1 < r->r_start;
 	     s = TAILQ_NEXT(s, r_link))
 		;
 
+	/* If we ran off the end of the list, insert at the tail. */
 	if (s == NULL) {
 		TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link);
 	} else {
-		TAILQ_INSERT_BEFORE(s, r, r_link);
+		/* Check for any overlap with the current region. */
+		if (r->r_start <= s->r_end && r->r_end >= s->r_start)
+			return EBUSY;
+
+		/* Check for any overlap with the next region. */
+		t = TAILQ_NEXT(s, r_link);
+		if (t && r->r_start <= t->r_end && r->r_end >= t->r_start)
+			return EBUSY;
+
+		/*
+		 * See if this region can be merged with the next region.  If
+		 * not, clear the pointer.
+		 */
+		if (t && (r->r_end + 1 != t->r_start || t->r_flags != 0))
+			t = NULL;
+
+		/* See if we can merge with the current region. */
+		if (s->r_end + 1 == r->r_start && s->r_flags == 0) {
+			/* Can we merge all 3 regions? */
+			if (t != NULL) {
+				s->r_end = t->r_end;
+				TAILQ_REMOVE(&rm->rm_list, t, r_link);
+				free(r, M_RMAN);
+				free(t, M_RMAN);
+			} else {
+				s->r_end = r->r_end;
+				free(r, M_RMAN);
+			}
+		} else {
+			/* Can we merge with just the next region? */
+			if (t != NULL) {
+				t->r_start = r->r_start;
+				free(r, M_RMAN);
+			} else
+				TAILQ_INSERT_BEFORE(s, r, r_link);
+		}
 	}
 
 	mtx_unlock(rm->rm_mtx);