Use dedicated lock name for pbufs

(cherry picked from commit 531f8cf)

sys/kern/vfs_bio.c

@@ -400,12 +400,6 @@ struct bufqueue __exclusive_cache_line bqempty;
  */
 uma_zone_t buf_zone;
 
-/*
- * Single global constant for BUF_WMESG, to avoid getting multiple references.
- * buf_wmesg is referred from macros.
- */
-const char *buf_wmesg = BUF_WMESG;
-
 static int
 sysctl_runningspace(SYSCTL_HANDLER_ARGS)
 {
@@ -1175,6 +1169,12 @@ kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est)
 	return (v);
 }
 
+/*
+ * Single global constant for BUF_WMESG, to avoid getting multiple
+ * references.
+ */
+static const char buf_wmesg[] = "bufwait";
+
 /* Initialize the buffer subsystem.  Called before use of any buffers. */
 void
 bufinit(void)
@@ -1205,7 +1205,7 @@ bufinit(void)
 		bp->b_xflags = 0;
 		bp->b_data = bp->b_kvabase = unmapped_buf;
 		LIST_INIT(&bp->b_dep);
-		BUF_LOCKINIT(bp);
+		BUF_LOCKINIT(bp, buf_wmesg);
 		bq_insert(&bqempty, bp, false);
 	}
 

sys/sys/buf.h

@@ -291,16 +291,14 @@ struct buf {
 /*
  * Buffer locking
  */
-extern const char *buf_wmesg;		/* Default buffer lock message */
-#define BUF_WMESG "bufwait"
 #include <sys/proc.h>			/* XXX for curthread */
 #include <sys/mutex.h>
 
 /*
  * Initialize a lock.
  */
-#define BUF_LOCKINIT(bp)						\
-	lockinit(&(bp)->b_lock, PRIBIO + 4, buf_wmesg, 0, LK_NEW)
+#define BUF_LOCKINIT(bp, wmesg)						\
+	lockinit(&(bp)->b_lock, PRIBIO + 4, wmesg, 0, LK_NEW)
 /*
  *
  * Get a lock sleeping non-interruptably until it becomes available.

sys/vm/vm_pager.c

@@ -480,6 +480,8 @@ pbuf_dtor(void *mem, int size, void *arg)
 	BUF_UNLOCK(bp);
 }
 
+static const char pbuf_wmesg[] = "pbufwait";
+
 static int
 pbuf_init(void *mem, int size, int flags)
 {
@@ -489,7 +491,7 @@ pbuf_init(void *mem, int size, int flags)
 	if (bp->b_kvabase == NULL)
 		return (ENOMEM);
 	bp->b_kvasize = ptoa(PBUF_PAGES);
-	BUF_LOCKINIT(bp);
+	BUF_LOCKINIT(bp, pbuf_wmesg);
 	LIST_INIT(&bp->b_dep);
 	bp->b_rcred = bp->b_wcred = NOCRED;
 	bp->b_xflags = 0;