[tip: x86/mm] mm: Remove pointless barrier() after pmdp_get_lockless()

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the x86/mm branch of tip:

Commit-ID:     eb780dcae02d5a71e6979aa7b8c708dea8597adf
Gitweb:        https://git.kernel.org/tip/eb780dcae02d5a71e6979aa7b8c708dea8597adf
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Fri, 21 Oct 2022 13:47:29 +02:00
Committer:     Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Thu, 15 Dec 2022 10:37:27 -08:00

mm: Remove pointless barrier() after pmdp_get_lockless()

pmdp_get_lockless() should itself imply any ordering required.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20221022114425.298833095%40infradead.org
---
 mm/hmm.c    | 1 -
 mm/vmscan.c | 3 ---
 2 files changed, 4 deletions(-)

diff --git a/mm/hmm.c b/mm/hmm.c
index 39cf50d..601a99c 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -362,7 +362,6 @@ again:
 		 * values.
 		 */
 		pmd = pmdp_get_lockless(pmdp);
-		barrier();
 		if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))
 			goto again;
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 88ef873..4936a88 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4041,9 +4041,6 @@ restart:
 	for (i = pmd_index(start), addr = start; addr != end; i++, addr = next) {
 		pmd_t val = pmdp_get_lockless(pmd + i);
 
-		/* for pmdp_get_lockless() */
-		barrier();
-
 		next = pmd_addr_end(addr, end);
 
 		if (!pmd_present(val) || is_huge_zero_pmd(val)) {