11927 Log, or optionally panic, on zero-length kmem allocations
Reviewed by: Dan McDonald <danmcd@joyent.com>
Reviewed by: Jason King <jason.brian.king@gmail.com>

*** 23,33 ****
  /*
   * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma ident   "%Z%%M% %I%     %E% SMI"
  
  #include <sys/smbios_impl.h>
  #include <sys/cmn_err.h>
  #include <sys/varargs.h>
  #include <sys/systm.h>
--- 23,35 ----
  /*
   * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! /*
!  * Copyright (c) 2015 Joyent, Inc.  All rights reserved.
!  */
  
  #include <sys/smbios_impl.h>
  #include <sys/cmn_err.h>
  #include <sys/varargs.h>
  #include <sys/systm.h>
*** 41,57 ****
  }
  
  void *
  smb_alloc(size_t len)
  {
!         return (kmem_alloc(len, KM_SLEEP));
  }
  
  void *
  smb_zalloc(size_t len)
  {
!         return (kmem_zalloc(len, KM_SLEEP));
  }
  
  void
  smb_free(void *buf, size_t len)
  {
--- 43,59 ----
  }
  
  void *
  smb_alloc(size_t len)
  {
!         return (len > 0 ? kmem_alloc(len, KM_SLEEP) : NULL);
  }
  
  void *
  smb_zalloc(size_t len)
  {
!         return (len > 0 ? kmem_zalloc(len, KM_SLEEP) : NULL);
  }
  
  void
  smb_free(void *buf, size_t len)
  {