* 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.

4 files changed, 60 insertions, 55 deletions

diff --git a/sys/kern/kern_mbuf.c b/sys/kern/kern_mbuf.c
index f2badd6..c2b749f 100644
--- a/sys/kern/kern_mbuf.c
+++ b/sys/kern/kern_mbuf.c
@@ -111,13 +111,13 @@ uma_zone_t	zone_pack;
 /*
  * Local prototypes.
  */
-static void	mb_ctor_mbuf(void *, int, void *);
-static void	mb_ctor_clust(void *, int, void *);
-static void	mb_ctor_pack(void *, int, void *);
+static int	mb_ctor_mbuf(void *, int, void *, int);
+static int	mb_ctor_clust(void *, int, void *, int);
+static int	mb_ctor_pack(void *, int, void *, int);
 static void	mb_dtor_mbuf(void *, int, void *);
 static void	mb_dtor_clust(void *, int, void *);	/* XXX */
 static void	mb_dtor_pack(void *, int, void *);	/* XXX */
-static void	mb_init_pack(void *, int);
+static int	mb_init_pack(void *, int, int);
 static void	mb_fini_pack(void *, int);
 
 static void	mb_reclaim(void *);
@@ -180,19 +180,20 @@ mbuf_init(void *dummy)
  * contains call-specific information required to support the
  * mbuf allocation API.
  */
-static void
-mb_ctor_mbuf(void *mem, int size, void *arg)
+static int
+mb_ctor_mbuf(void *mem, int size, void *arg, int how)
 {
 	struct mbuf *m;
 	struct mb_args *args;
+#ifdef MAC
+	int error;
+#endif
 	int flags;
-	int how;
 	short type;
 
 	m = (struct mbuf *)mem;
 	args = (struct mb_args *)arg;
 	flags = args->flags;
-	how = args->how;
 	type = args->type;
 
 	m->m_type = type;
@@ -206,17 +207,14 @@ mb_ctor_mbuf(void *mem, int size, void *arg)
 		SLIST_INIT(&m->m_pkthdr.tags);
 #ifdef MAC
 		/* If the label init fails, fail the alloc */
-		if (mac_init_mbuf(m, how) != 0) {
-			m_free(m);
-/* XXX*/		panic("mb_ctor_mbuf(): can't deal with failure!");
-/*			return 0; */
-		}
+		error = mac_init_mbuf(m, how);
+		if (error)
+			return (error);
 #endif
 	} else
 		m->m_data = m->m_dat;
 	mbstat.m_mbufs += 1;	/* XXX */
-/*	return 1;
-*/
+	return (0);
 }
 
 /*
@@ -252,8 +250,8 @@ mb_dtor_pack(void *mem, int size, void *arg)
  * Here the 'arg' pointer points to the Mbuf which we
  * are configuring cluster storage for.
  */
-static void
-mb_ctor_clust(void *mem, int size, void *arg)
+static int
+mb_ctor_clust(void *mem, int size, void *arg, int how)
 {
 	struct mbuf *m;
 
@@ -269,8 +267,7 @@ mb_ctor_clust(void *mem, int size, void *arg)
 	    m->m_ext.ext_buf);
 	*(m->m_ext.ref_cnt) = 1;
 	mbstat.m_mclusts += 1;	/* XXX */
-/*	return 1;
-*/
+	return (0);
 }
 
 /* XXX */
@@ -284,17 +281,18 @@ mb_dtor_clust(void *mem, int size, void *arg)
  * The Packet secondary zone's init routine, executed on the
  * object's transition from keg slab to zone cache.
  */
-static void
-mb_init_pack(void *mem, int size)
+static int
+mb_init_pack(void *mem, int size, int how)
 {
 	struct mbuf *m;
 
 	m = (struct mbuf *)mem;
 	m->m_ext.ext_buf = NULL;
-	uma_zalloc_arg(zone_clust, m, M_NOWAIT);
-	if (m->m_ext.ext_buf == NULL)	/* XXX */
-		panic("mb_init_pack(): Can't deal with failure yet.");
+	uma_zalloc_arg(zone_clust, m, how);
+	if (m->m_ext.ext_buf == NULL)
+		return (ENOMEM);
 	mbstat.m_mclusts -= 1;	/* XXX */
+	return (0);
 }
 
 /*
@@ -315,19 +313,21 @@ mb_fini_pack(void *mem, int size)
 /*
  * The "packet" keg constructor.
  */
-static void
-mb_ctor_pack(void *mem, int size, void *arg)
+static int
+mb_ctor_pack(void *mem, int size, void *arg, int how)
 {
 	struct mbuf *m;
 	struct mb_args *args;
-	int flags, how;
+#ifdef MAC
+	int error;
+#endif
+	int flags;
 	short type;
 
 	m = (struct mbuf *)mem;
 	args = (struct mb_args *)arg;
 	flags = args->flags;
 	type = args->type;
-	how = args->how;
 
 	m->m_type = type;
 	m->m_next = NULL;
@@ -346,17 +346,14 @@ mb_ctor_pack(void *mem, int size, void *arg)
 		SLIST_INIT(&m->m_pkthdr.tags);
 #ifdef MAC
 		/* If the label init fails, fail the alloc */
-		if (mac_init_mbuf(m, how) != 0) {
-			m_free(m);
-/* XXX*/		panic("mb_ctor_pack(): can't deal with failure!");
-/*			return 0; */
-		}
+		error = mac_init_mbuf(m, how);
+		if (error)
+			return (error);
 #endif
 	}
 	mbstat.m_mbufs += 1;	/* XXX */
 	mbstat.m_mclusts += 1;	/* XXX */
-/*	return 1;
-*/
+	return (0);
 }
 
 /*
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index a83b9e1..a104ae4 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -74,9 +74,9 @@ static void doenterpgrp(struct proc *, struct pgrp *);
 static void orphanpg(struct pgrp *pg);
 static void pgadjustjobc(struct pgrp *pgrp, int entering);
 static void pgdelete(struct pgrp *);
-static void proc_ctor(void *mem, int size, void *arg);
+static int proc_ctor(void *mem, int size, void *arg, int flags);
 static void proc_dtor(void *mem, int size, void *arg);
-static void proc_init(void *mem, int size);
+static int proc_init(void *mem, int size, int flags);
 static void proc_fini(void *mem, int size);
 
 /*
@@ -128,12 +128,13 @@ procinit()
 /*
  * Prepare a proc for use.
  */
-static void
-proc_ctor(void *mem, int size, void *arg)
+static int
+proc_ctor(void *mem, int size, void *arg, int flags)
 {
 	struct proc *p;
 
 	p = (struct proc *)mem;
+	return (0);
 }
 
 /*
@@ -178,8 +179,8 @@ proc_dtor(void *mem, int size, void *arg)
 /*
  * Initialize type-stable parts of a proc (when newly created).
  */
-static void
-proc_init(void *mem, int size)
+static int
+proc_init(void *mem, int size, int flags)
 {
 	struct proc *p;
 	struct thread *td;
@@ -195,6 +196,7 @@ proc_init(void *mem, int size)
 	proc_linkup(p, kg, ke, td);
 	bzero(&p->p_mtx, sizeof(struct mtx));
 	mtx_init(&p->p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
+	return (0);
 }
 
 /*
diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
index c5e9504..7f6ef95 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -143,8 +143,8 @@ MTX_SYSINIT(tid_lock, &tid_lock, "TID lock", MTX_DEF);
 /*
  * Prepare a thread for use.
  */
-static void
-thread_ctor(void *mem, int size, void *arg)
+static int
+thread_ctor(void *mem, int size, void *arg, int flags)
 {
 	struct thread	*td;
 
@@ -165,6 +165,7 @@ thread_ctor(void *mem, int size, void *arg)
 	 * next thread.
 	 */
 	td->td_critnest = 1;
+	return (0);
 }
 
 /*
@@ -202,8 +203,8 @@ thread_dtor(void *mem, int size, void *arg)
 /*
  * Initialize type-stable parts of a thread (when newly created).
  */
-static void
-thread_init(void *mem, int size)
+static int
+thread_init(void *mem, int size, int flags)
 {
 	struct thread *td;
 	struct tid_bitmap_part *bmp, *new;
@@ -251,6 +252,7 @@ thread_init(void *mem, int size)
 	td->td_sleepqueue = sleepq_alloc();
 	td->td_turnstile = turnstile_alloc();
 	td->td_sched = (struct td_sched *)&td[1];
+	return (0);
 }
 
 /*
@@ -287,25 +289,27 @@ thread_fini(void *mem, int size)
 /*
  * Initialize type-stable parts of a kse (when newly created).
  */
-static void
-kse_init(void *mem, int size)
+static int
+kse_init(void *mem, int size, int flags)
 {
 	struct kse	*ke;
 
 	ke = (struct kse *)mem;
 	ke->ke_sched = (struct ke_sched *)&ke[1];
+	return (0);
 }
 
 /*
  * Initialize type-stable parts of a ksegrp (when newly created).
  */
-static void
-ksegrp_init(void *mem, int size)
+static int
+ksegrp_init(void *mem, int size, int flags)
 {
 	struct ksegrp	*kg;
 
 	kg = (struct ksegrp *)mem;
 	kg->kg_sched = (struct kg_sched *)&kg[1];
+	return (0);
 }
 
 /*
diff --git a/sys/kern/sys_pipe.c b/sys/kern/sys_pipe.c
index 03f88e1..9efdc54 100644
--- a/sys/kern/sys_pipe.c
+++ b/sys/kern/sys_pipe.c
@@ -182,9 +182,9 @@ static void pipe_clone_write_buffer(struct pipe *wpipe);
 static int pipespace(struct pipe *cpipe, int size);
 static int pipespace_new(struct pipe *cpipe, int size);
 
-static void	pipe_zone_ctor(void *mem, int size, void *arg);
+static int	pipe_zone_ctor(void *mem, int size, void *arg, int flags);
 static void	pipe_zone_dtor(void *mem, int size, void *arg);
-static void	pipe_zone_init(void *mem, int size);
+static int	pipe_zone_init(void *mem, int size, int flags);
 static void	pipe_zone_fini(void *mem, int size);
 
 static uma_zone_t pipe_zone;
@@ -201,8 +201,8 @@ pipeinit(void *dummy __unused)
 	KASSERT(pipe_zone != NULL, ("pipe_zone not initialized"));
 }
 
-static void
-pipe_zone_ctor(void *mem, int size, void *arg)
+static int
+pipe_zone_ctor(void *mem, int size, void *arg, int flags)
 {
 	struct pipepair *pp;
 	struct pipe *rpipe, *wpipe;
@@ -247,6 +247,7 @@ pipe_zone_ctor(void *mem, int size, void *arg)
 	pp->pp_label = NULL;
 
 	atomic_add_int(&amountpipes, 2);
+	return (0);
 }
 
 static void
@@ -261,8 +262,8 @@ pipe_zone_dtor(void *mem, int size, void *arg)
 	atomic_subtract_int(&amountpipes, 2);
 }
 
-static void
-pipe_zone_init(void *mem, int size)
+static int
+pipe_zone_init(void *mem, int size, int flags)
 {
 	struct pipepair *pp;
 
@@ -271,6 +272,7 @@ pipe_zone_init(void *mem, int size)
 	pp = (struct pipepair *)mem;
 
 	mtx_init(&pp->pp_mtx, "pipe mutex", NULL, MTX_DEF | MTX_RECURSE);
+	return (0);
 }
 
 static void