1 files changed, 41 insertions, 24 deletions

diff --git a/usr/src/uts/common/os/lwp.c b/usr/src/uts/common/os/lwp.c
index feb8e76c42..f5be1b40b3 100644
--- a/usr/src/uts/common/os/lwp.c
+++ b/usr/src/uts/common/os/lwp.c
@@ -25,7 +25,7 @@
  */
 
 /*
- * Copyright (c) 2013, Joyent, Inc. All rights reserved.
+ * Copyright 2015, Joyent, Inc.
  */
 
 #include <sys/param.h>
@@ -115,7 +115,7 @@ lwp_create(void (*proc)(), caddr_t arg, size_t len, proc_t *p,
 	ret_tidhash_t *ret_tidhash = NULL;
 	int i;
 	int rctlfail = 0;
-	boolean_t branded = 0;
+	void *brand_data = NULL;
 	struct ctxop *ctx = NULL;
 
 	ASSERT(cid != sysdccid);	/* system threads must start in SYS */
@@ -283,6 +283,19 @@ lwp_create(void (*proc)(), caddr_t arg, size_t len, proc_t *p,
 	 */
 	lep = kmem_zalloc(sizeof (*lep), KM_SLEEP);
 
+	/*
+	 * If necessary, speculatively allocate lwp brand data.  This is done
+	 * ahead of time so p_lock need not be dropped during lwp branding.
+	 */
+	if (PROC_IS_BRANDED(p) && BROP(p)->b_lwpdata_alloc != NULL) {
+		if ((brand_data = BROP(p)->b_lwpdata_alloc(p)) == NULL) {
+			mutex_enter(&p->p_lock);
+			err = 1;
+			atomic_inc_32(&p->p_zone->zone_ffmisc);
+			goto error;
+		}
+	}
+
 	mutex_enter(&p->p_lock);
 grow:
 	/*
@@ -630,18 +643,6 @@ grow:
 		} while (lwp_hash_lookup(p, t->t_tid) != NULL);
 	}
 
-	/*
-	 * If this is a branded process, let the brand do any necessary lwp
-	 * initialization.
-	 */
-	if (PROC_IS_BRANDED(p)) {
-		if (BROP(p)->b_initlwp(lwp)) {
-			err = 1;
-			atomic_inc_32(&p->p_zone->zone_ffmisc);
-			goto error;
-		}
-		branded = 1;
-	}
 
 	if (t->t_tid == 1) {
 		kpreempt_disable();
@@ -654,7 +655,6 @@ grow:
 		}
 	}
 
-	p->p_lwpcnt++;
 	t->t_waitfor = -1;
 
 	/*
@@ -695,9 +695,21 @@ grow:
 	t->t_pre_sys = 1;
 	t->t_post_sys = 1;
 
+	/* Complete branded lwp initialization */
+	if (PROC_IS_BRANDED(p)) {
+		BROP(p)->b_initlwp(lwp, brand_data);
+		/*
+		 * The b_initlwp hook is expected to consume any preallocated
+		 * brand_data in a way that prepares it for deallocation by the
+		 * b_freelwp hook.
+		 */
+		brand_data = NULL;
+	}
+
 	/*
 	 * Insert the new thread into the list of all threads.
 	 */
+	p->p_lwpcnt++;
 	if ((tx = p->p_tlist) == NULL) {
 		t->t_back = t;
 		t->t_forw = t;
@@ -753,8 +765,9 @@ error:
 		if (cid != NOCLASS && bufp != NULL)
 			CL_FREE(cid, bufp);
 
-		if (branded)
-			BROP(p)->b_freelwp(lwp);
+		if (brand_data != NULL) {
+			BROP(p)->b_lwpdata_free(brand_data);
+		}
 
 		mutex_exit(&p->p_lock);
 		t->t_state = TS_FREE;
@@ -891,13 +904,6 @@ lwp_exit(void)
 	if (t->t_upimutex != NULL)
 		upimutex_cleanup();
 
-	/*
-	 * Perform any brand specific exit processing, then release any
-	 * brand data associated with the lwp
-	 */
-	if (PROC_IS_BRANDED(p))
-		BROP(p)->b_lwpexit(lwp);
-
 	lwp_pcb_exit();
 
 	mutex_enter(&p->p_lock);
@@ -941,6 +947,17 @@ lwp_exit(void)
 	DTRACE_PROC(lwp__exit);
 
 	/*
+	 * Perform any brand specific exit processing, then release any
+	 * brand data associated with the lwp
+	 */
+	if (PROC_IS_BRANDED(p)) {
+		mutex_exit(&p->p_lock);
+		BROP(p)->b_lwpexit(lwp);
+		BROP(p)->b_freelwp(lwp);
+		mutex_enter(&p->p_lock);
+	}
+
+	/*
 	 * If the lwp is a detached lwp or if the process is exiting,
 	 * remove (lwp_hash_out()) the lwp from the lwp directory.
 	 * Otherwise null out the lwp's le_thread pointer in the lwp