MFC r268780

Nuke the never-used RF_TIMESHARE feature, reducing the complexity of the
code.  The consensus on arch@ is that this feature might have been useful
in the distant past, but is now just unnecessary bloat.

The int_rman_activate_resource() and int_rman_deactivate_resource()
functions become trivial, so manually inline them.

The special deferred handling of RF_ACTIVE is no longer needed in
reserve_resource_bound(), so eliminate the associated code at the
end of the function.

These changes reduce the object file size by more than 500 bytes on i386.

Update the rman.9 man page to reflect the removal of the RF_TIMESHARE
feature.

3 files changed, 16 insertions, 113 deletions

diff --git a/share/man/man9/rman.9 b/share/man/man9/rman.9
index d9a2092..4c8ef29 100644
--- a/share/man/man9/rman.9
+++ b/share/man/man9/rman.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 29, 2011
+.Dd July 15, 2014
 .Dt RMAN 9
 .Os
 .Sh NAME
@@ -141,13 +141,11 @@ represented by a 16-bit flag register, as follows.
 #define RF_ALLOCATED    0x0001 /* resource has been reserved */
 #define RF_ACTIVE       0x0002 /* resource allocation has been activated */
 #define RF_SHAREABLE    0x0004 /* resource permits contemporaneous sharing */
-#define RF_TIMESHARE    0x0008 /* resource permits time-division sharing */
-#define RF_WANTED       0x0010 /* somebody is waiting for this resource */
 #define RF_FIRSTSHARE   0x0020 /* first in sharing list */
 #define RF_PREFETCHABLE 0x0040 /* resource is prefetchable */
 .Ed
 .Pp
-The remainder of the flag bits are used to represent the desired alignment
+Bits 15:10  of the flag register are used to represent the desired alignment
 of the resource within the region.
 .Pp
 The
@@ -299,12 +297,9 @@ The
 .Fa bound
 argument must be a power of two.
 It may be set to zero to specify no boundary restriction.
-The default behavior is to allocate an exclusive segment, unless the
+A shared segment will be allocated if the
 .Dv RF_SHAREABLE
-or
-.Dv RF_TIMESHARE
-flags are set, in which case a shared
-segment will be allocated.
+flag is set, otherwise an exclusive segment will be allocated.
 If this shared segment already exists, the caller has its device
 added to the list of consumers.
 .Pp
diff --git a/sys/kern/subr_rman.c b/sys/kern/subr_rman.c
index cc41e29..568f566 100644
--- a/sys/kern/subr_rman.c
+++ b/sys/kern/subr_rman.c
@@ -110,9 +110,6 @@ static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager");
 
 struct rman_head rman_head;
 static struct mtx rman_mtx; /* mutex to protect rman_head */
-static int int_rman_activate_resource(struct rman *rm, struct resource_i *r,
-				       struct resource_i **whohas);
-static int int_rman_deactivate_resource(struct resource_i *r);
 static int int_rman_release_resource(struct rman *rm, struct resource_i *r);
 
 static __inline struct resource_i *
@@ -322,7 +319,7 @@ rman_adjust_resource(struct resource *rr, u_long start, u_long end)
 
 	/* Not supported for shared resources. */
 	r = rr->__r_i;
-	if (r->r_flags & (RF_TIMESHARE | RF_SHAREABLE))
+	if (r->r_flags & RF_SHAREABLE)
 		return (EINVAL);
 
 	/*
@@ -435,7 +432,7 @@ rman_adjust_resource(struct resource *rr, u_long start, u_long end)
 	return (0);
 }
 
-#define	SHARE_TYPE(f)	(f & (RF_SHAREABLE | RF_TIMESHARE | RF_PREFETCHABLE))
+#define	SHARE_TYPE(f)	(f & (RF_SHAREABLE | RF_PREFETCHABLE))
 
 struct resource *
 rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
@@ -452,10 +449,9 @@ rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
 	       "length %#lx, flags %u, device %s\n", rm->rm_descr, start, end,
 	       count, flags,
 	       dev == NULL ? "<null>" : device_get_nameunit(dev)));
-	KASSERT((flags & (RF_WANTED | RF_FIRSTSHARE)) == 0,
+	KASSERT((flags & RF_FIRSTSHARE) == 0,
 	    ("invalid flags %#x", flags));
-	new_rflags = (flags & ~(RF_ACTIVE | RF_WANTED | RF_FIRSTSHARE)) |
-	    RF_ALLOCATED;
+	new_rflags = (flags & ~RF_FIRSTSHARE) | RF_ALLOCATED;
 
 	mtx_lock(rm->rm_mtx);
 
@@ -601,7 +597,7 @@ rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
 	 * additional work, but this does not seem warranted.)
 	 */
 	DPRINTF(("no unshared regions found\n"));
-	if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0)
+	if ((flags & RF_SHAREABLE) == 0)
 		goto out;
 
 	for (s = r; s && s->r_end <= end; s = TAILQ_NEXT(s, r_link)) {
@@ -636,25 +632,11 @@ rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
 			goto out;
 		}
 	}
-
 	/*
 	 * We couldn't find anything.
 	 */
-out:
-	/*
-	 * If the user specified RF_ACTIVE in flags, we attempt to atomically
-	 * activate the resource.  If this fails, we release the resource
-	 * and indicate overall failure.  (This behavior probably doesn't
-	 * make sense for RF_TIMESHARE-type resources.)
-	 */
-	if (rv && (flags & RF_ACTIVE) != 0) {
-		struct resource_i *whohas;
-		if (int_rman_activate_resource(rm, rv, &whohas)) {
-			int_rman_release_resource(rm, rv);
-			rv = NULL;
-		}
-	}
 
+out:
 	mtx_unlock(rm->rm_mtx);
 	return (rv == NULL ? NULL : &rv->r_r);
 }
@@ -668,91 +650,17 @@ rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
 	    dev));
 }
 
-static int
-int_rman_activate_resource(struct rman *rm, struct resource_i *r,
-			   struct resource_i **whohas)
-{
-	struct resource_i *s;
-	int ok;
-
-	/*
-	 * If we are not timesharing, then there is nothing much to do.
-	 * If we already have the resource, then there is nothing at all to do.
-	 * If we are not on a sharing list with anybody else, then there is
-	 * little to do.
-	 */
-	if ((r->r_flags & RF_TIMESHARE) == 0
-	    || (r->r_flags & RF_ACTIVE) != 0
-	    || r->r_sharehead == NULL) {
-		r->r_flags |= RF_ACTIVE;
-		return 0;
-	}
-
-	ok = 1;
-	for (s = LIST_FIRST(r->r_sharehead); s && ok;
-	     s = LIST_NEXT(s, r_sharelink)) {
-		if ((s->r_flags & RF_ACTIVE) != 0) {
-			ok = 0;
-			*whohas = s;
-		}
-	}
-	if (ok) {
-		r->r_flags |= RF_ACTIVE;
-		return 0;
-	}
-	return EBUSY;
-}
-
 int
 rman_activate_resource(struct resource *re)
 {
-	int rv;
-	struct resource_i *r, *whohas;
+	struct resource_i *r;
 	struct rman *rm;
 
 	r = re->__r_i;
 	rm = r->r_rm;
 	mtx_lock(rm->rm_mtx);
-	rv = int_rman_activate_resource(rm, r, &whohas);
+	r->r_flags |= RF_ACTIVE;
 	mtx_unlock(rm->rm_mtx);
-	return rv;
-}
-
-int
-rman_await_resource(struct resource *re, int pri, int timo)
-{
-	int rv;
-	struct resource_i *r, *whohas;
-	struct rman *rm;
-
-	r = re->__r_i;
-	rm = r->r_rm;
-	mtx_lock(rm->rm_mtx);
-	for (;;) {
-		rv = int_rman_activate_resource(rm, r, &whohas);
-		if (rv != EBUSY)
-			return (rv);	/* returns with mutex held */
-
-		if (r->r_sharehead == NULL)
-			panic("rman_await_resource");
-		whohas->r_flags |= RF_WANTED;
-		rv = msleep(r->r_sharehead, rm->rm_mtx, pri, "rmwait", timo);
-		if (rv) {
-			mtx_unlock(rm->rm_mtx);
-			return (rv);
-		}
-	}
-}
-
-static int
-int_rman_deactivate_resource(struct resource_i *r)
-{
-
-	r->r_flags &= ~RF_ACTIVE;
-	if (r->r_flags & RF_WANTED) {
-		r->r_flags &= ~RF_WANTED;
-		wakeup(r->r_sharehead);
-	}
 	return 0;
 }
 
@@ -763,7 +671,7 @@ rman_deactivate_resource(struct resource *r)
 
 	rm = r->__r_i->r_rm;
 	mtx_lock(rm->rm_mtx);
-	int_rman_deactivate_resource(r->__r_i);
+	r->__r_i->r_flags &= ~RF_ACTIVE;
 	mtx_unlock(rm->rm_mtx);
 	return 0;
 }
@@ -774,7 +682,7 @@ int_rman_release_resource(struct rman *rm, struct resource_i *r)
 	struct resource_i *s, *t;
 
 	if (r->r_flags & RF_ACTIVE)
-		int_rman_deactivate_resource(r);
+		r->r_flags &= ~RF_ACTIVE;
 
 	/*
 	 * Check for a sharing list first.  If there is one, then we don't
diff --git a/sys/sys/rman.h b/sys/sys/rman.h
index 1914a72..d98dac7 100644
--- a/sys/sys/rman.h
+++ b/sys/sys/rman.h
@@ -42,8 +42,8 @@
 #define	RF_ALLOCATED	0x0001	/* resource has been reserved */
 #define	RF_ACTIVE	0x0002	/* resource allocation has been activated */
 #define	RF_SHAREABLE	0x0004	/* resource permits contemporaneous sharing */
-#define	RF_TIMESHARE	0x0008	/* resource permits time-division sharing */
-#define	RF_WANTED	0x0010	/* somebody is waiting for this resource */
+#define	RF_SPARE1	0x0008
+#define	RF_SPARE2	0x0010
 #define	RF_FIRSTSHARE	0x0020	/* first in sharing list */
 #define	RF_PREFETCHABLE	0x0040	/* resource is prefetchable */
 #define	RF_OPTIONAL	0x0080	/* for bus_alloc_resources() */