5045 use atomic_{inc,dec}_* instead of atomic_add_*

*** 612,622 ****
           * Direct Writes
           */
  
          if (!exclusive) {
                  ufs_shared_writes++;
!                 ncur = atomic_add_32_nv(&ufs_cur_writes, 1);
                  if (ncur > ufs_maxcur_writes)
                          ufs_maxcur_writes = ncur;
          }
  
          /*
--- 612,622 ----
           * Direct Writes
           */
  
          if (!exclusive) {
                  ufs_shared_writes++;
!                 ncur = atomic_inc_32_nv(&ufs_cur_writes);
                  if (ncur > ufs_maxcur_writes)
                          ufs_maxcur_writes = ncur;
          }
  
          /*
*** 725,735 ****
                  as_pageunlock(as, pplist, pglck_base, pglck_size, S_READ);
  
          }
  
          if (!exclusive) {
!                 atomic_add_32(&ufs_cur_writes, -1);
                  /*
                   * If this write was done shared, readers may
                   * have pulled in unmodified pages. Get rid of
                   * these potentially stale pages.
                   */
--- 725,735 ----
                  as_pageunlock(as, pplist, pglck_base, pglck_size, S_READ);
  
          }
  
          if (!exclusive) {
!                 atomic_dec_32(&ufs_cur_writes);
                  /*
                   * If this write was done shared, readers may
                   * have pulled in unmodified pages. Get rid of
                   * these potentially stale pages.
                   */