Re: [RFC PATCH 02/11] mm/mempolicy: swap cond reference counting logic in do_get_mempolicy

[restoring the CC list, I supect you didn't want this to be a private
discussion]

On Tue 28-11-23 09:10:18, Gregory Price wrote:

On Tue, Nov 28, 2023 at 03:07:10PM +0100, Michal Hocko wrote:

quoted

On Wed 22-11-23 16:11:51, Gregory Price wrote:
[...]

quoted

@@ -982,11 +991,11 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 	}
 
  out:
-	mpol_cond_put(pol);
+	mpol_put(pol);
 	if (vma)
 		mmap_read_unlock(mm);
 	if (pol_refcount)
-		mpol_put(pol_refcount);
+		mpol_cond_put(pol_refcount);

Maybe I am just misreading the patch but pol_refcount should be always
NULL with this patch

earlier:

+               pol = pol_refcount = __get_vma_policy(vma, addr, &ilx);

i can split this into two lines if preferred.

If addr is not set, then yes pol_refcount is always null.

My bad, missed that. Making that two lines would be easier to read but
nothing I would insist on of course.

-- 
Michal Hocko
SUSE Labs