On Thu, Jan 24, 2019 at 2:19 PM Javier González [off-list ref] wrote:

quoted

On 22 Jan 2019, at 11.15, hans@owltronix.com wrote:

From: Hans Holmberg <redacted>

pblk_line_meta_free might sleep (it can end up calling vfree, depending
on how we allocate lba lists), and this can lead to a BUG()
if we wake up on a different cpu and release the lock.

As there is no point of grabbing the free lock when pblk has shut down,
remove the lock.

Signed-off-by: Hans Holmberg <redacted>
---
drivers/lightnvm/pblk-init.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index f9a3e47b6a93..eb0135c77805 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c

@@ -584,14 +584,12 @@ static void pblk_lines_free(struct pblk *pblk)
      struct pblk_line *line;
      int i;

-     spin_lock(&l_mg->free_lock);
      for (i = 0; i < l_mg->nr_lines; i++) {
              line = &pblk->lines[i];

              pblk_line_free(line);
              pblk_line_meta_free(l_mg, line);
      }
-     spin_unlock(&l_mg->free_lock);

      pblk_line_mg_free(pblk);

--

2.17.1

Can you add a comment too indicating that this is only safe on a single
threaded shutdown?

To be able to free the lines, we need have stopped anything accessing
the lines first. That seems obvious to me.

It would be nice to make a pass over the code and document pblk's
locking(and other concurrency handling, like the line krefs) though.

Thanks,
Hans

Otherwise the patch looks good.

Reviewed-by: Javier González <redacted>