* Add a "how" argument to uma_zone constructors and initialization functions

  so that they know whether the allocation is supposed to be able to sleep
  or not.
* Allow uma_zone constructors and initialation functions to return either
  success or error.  Almost all of the ones in the tree currently return
  success unconditionally, but mbuf is a notable exception: the packet
  zone constructor wants to be able to fail if it cannot suballocate an
  mbuf cluster, and the mbuf allocators want to be able to fail in general
  in a MAC kernel if the MAC mbuf initializer fails.  This fixes the
  panics people are seeing when they run out of memory for mbuf clusters.
* Allow debug.nosleepwithlocks on WITNESS to be disabled, without changing
  the default.

Both bmilekic and jeff have reviewed the changes made to make failable
zone allocations work.

1 files changed, 4 insertions, 3 deletions

diff --git a/sys/security/mac/mac_label.c b/sys/security/mac/mac_label.c
index eedc1dfaa3d9..19bd5b06e362 100644
--- a/sys/security/mac/mac_label.c
+++ b/sys/security/mac/mac_label.c
@@ -45,7 +45,7 @@ __FBSDID("$FreeBSD$");
 
 uma_zone_t	zone_label;
 
-static void	mac_labelzone_ctor(void *mem, int size, void *arg);
+static int	mac_labelzone_ctor(void *mem, int size, void *arg, int flags);
 static void	mac_labelzone_dtor(void *mem, int size, void *arg);
 
 void
@@ -57,8 +57,8 @@ mac_labelzone_init(void)
 	    UMA_ALIGN_PTR, 0);
 }
 
-static void
-mac_labelzone_ctor(void *mem, int size, void *arg)
+static int
+mac_labelzone_ctor(void *mem, int size, void *arg, int flags)
 {
 	struct label *label;
 
@@ -66,6 +66,7 @@ mac_labelzone_ctor(void *mem, int size, void *arg)
 	label = mem;
 	bzero(label, sizeof(*label));
 	label->l_flags = MAC_FLAG_INITIALIZED;
+	return (0);
 }
 
 static void