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Subject[PATCH v3 1/4] mm: vmalloc must set pte via arch code
Date
It is bad practice to directly set pte entries within a pte table.
Instead all modifications must go through arch-provided helpers such as
set_pte_at() to give the arch code visibility and allow it to check
(and potentially modify) the operation.

Fixes: 3e9a9e256b1e ("mm: add a vmap_pfn function")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
mm/vmalloc.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 9683573f1225..48202ec5f79a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2899,10 +2899,16 @@ struct vmap_pfn_data {
static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private)
{
struct vmap_pfn_data *data = private;
+ unsigned long pfn = data->pfns[data->idx];
+ pte_t ptent;

- if (WARN_ON_ONCE(pfn_valid(data->pfns[data->idx])))
+ if (WARN_ON_ONCE(pfn_valid(pfn)))
return -EINVAL;
- *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
+
+ ptent = pte_mkspecial(pfn_pte(pfn, data->prot));
+ set_pte_at(&init_mm, addr, pte, ptent);
+
+ data->idx++;
return 0;
}

--
2.25.1
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