Skip to content

Commit

Permalink
dlm: remove extra blocking callback check
Browse files Browse the repository at this point in the history
Just before delivering a blocking callback (bast), the dlm_astd
thread checks again that the granted mode of the lkb actually
blocks the mode requested by the bast.  The idea behind this was
originally that the granted mode may have changed since the bast
was queued, making the callback now unnecessary.  Reasons for
removing this extra check are:
- dlm_astd doesn't lock the rsb before reading the lkb grmode, so
  it's not technically safe (this removes the long standing FIXME)
- after running some tests, it doesn't appear the check ever actually
  eliminates a bast
- delivering an unnecessary blocking callback isn't a bad thing and
  can happen anyway

Signed-off-by: David Teigland <teigland@redhat.com>
  • Loading branch information
teigland committed Dec 23, 2008
1 parent d61e9aa commit 0333969
Showing 1 changed file with 1 addition and 6 deletions.
7 changes: 1 addition & 6 deletions fs/dlm/ast.c
Original file line number Diff line number Diff line change
Expand Up @@ -89,13 +89,8 @@ static void process_asts(void)
if ((type & AST_COMP) && cast)
cast(lkb->lkb_astparam);

/* FIXME: Is it safe to look at lkb_grmode here
without doing a lock_rsb() ?
Look at other checks in v1 to avoid basts. */

if ((type & AST_BAST) && bast)
if (!dlm_modes_compat(lkb->lkb_grmode, bmode))
bast(lkb->lkb_astparam, bmode);
bast(lkb->lkb_astparam, bmode);

/* this removes the reference added by dlm_add_ast
and may result in the lkb being freed */
Expand Down

0 comments on commit 0333969

Please sign in to comment.