From 7f48121e9fa82bdaf0bd0f7a7e49f48803c6c0e8 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 25 May 2023 14:57:08 +0200 Subject: [PATCH] mm/vmalloc: add missing READ/WRITE_ONCE() annotations 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@linutronix.de Signed-off-by: Thomas Gleixner Reviewed-by: Uladzislau Rezki (Sony) Reviewed-by: Christoph Hellwig Reviewed-by: Baoquan He Cc: Lorenzo Stoakes Signed-off-by: Andrew Morton --- mm/vmalloc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 679112e2ffd2..f643c7286c7a 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2094,9 +2094,9 @@ static bool purge_fragmented_block(struct vmap_block *vb, 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 cpu) 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, unsigned long size) 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);