The patch titled
Subject: mm/vmalloc: add missing READ/WRITE_ONCE() annotations
has been added to the -mm mm-unstable branch. Its filename is
mm-vmalloc-add-missing-read-write_once-annotations.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-add-missing-read-write_once-annotations.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Subject: mm/vmalloc: add missing READ/WRITE_ONCE() annotations
Date: Thu, 25 May 2023 14:57:08 +0200 (CEST)
purge_fragmented_blocks() accesses vmap_block::free and vmap_block::dirty
lockless for a quick check.
Add the missing READ/WRITE_ONCE() annotations.
Link: https://lkml.kernel.org/r/20230525124504.807356682@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/vmalloc.c~mm-vmalloc-add-missing-read-write_once-annotations
+++ a/mm/vmalloc.c
@@ -2094,9 +2094,9 @@ static bool purge_fragmented_block(struc
return false;
/* prevent further allocs after releasing lock */
- vb->free = 0;
+ WRITE_ONCE(vb->free, 0);
/* prevent purging it again */
- vb->dirty = VMAP_BBMAP_BITS;
+ WRITE_ONCE(vb->dirty, VMAP_BBMAP_BITS);
vb->dirty_min = 0;
vb->dirty_max = VMAP_BBMAP_BITS;
spin_lock(&vbq->lock);
@@ -2124,8 +2124,11 @@ static void purge_fragmented_blocks(int
rcu_read_lock();
list_for_each_entry_rcu(vb, &vbq->free, free_list) {
- if (vb->free + vb->dirty != VMAP_BBMAP_BITS ||
- vb->dirty == VMAP_BBMAP_BITS)
+ unsigned long free = READ_ONCE(vb->free);
+ unsigned long dirty = READ_ONCE(vb->dirty);
+
+ if (free + dirty != VMAP_BBMAP_BITS ||
+ dirty == VMAP_BBMAP_BITS)
continue;
spin_lock(&vb->lock);
@@ -2233,7 +2236,7 @@ static void vb_free(unsigned long addr,
vb->dirty_min = min(vb->dirty_min, offset);
vb->dirty_max = max(vb->dirty_max, offset + (1UL << order));
- vb->dirty += 1UL << order;
+ WRITE_ONCE(vb->dirty, vb->dirty + (1UL << order));
if (vb->dirty == VMAP_BBMAP_BITS) {
BUG_ON(vb->free);
spin_unlock(&vb->lock);
_
Patches currently in -mm which might be from tglx@xxxxxxxxxxxxx are
mm-vmalloc-prevent-stale-tlbs-in-fully-utilized-blocks.patch
mm-vmalloc-avoid-iterating-over-per-cpu-vmap-blocks-twice.patch
mm-vmalloc-prevent-flushing-dirty-space-over-and-over.patch
mm-vmalloc-check-free-space-in-vmap_block-lockless.patch
mm-vmalloc-add-missing-read-write_once-annotations.patch
mm-vmalloc-dont-purge-usable-blocks-unnecessarily.patch
