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Subject[PATCH v1 05/46] powerpc/kasan: Remove unnecessary page table locking
Date
Commit 45ff3c559585 ("powerpc/kasan: Fix parallel loading of
modules.") added spinlocks to manage parallele module loading.

Since then commit 47febbeeec44 ("powerpc/32: Force KASAN_VMALLOC for
modules") converted the module loading to KASAN_VMALLOC.

The spinlocking has then become unneeded and can be removed to
simplify kasan_init_shadow_page_tables()

Also remove inclusion of linux/moduleloader.h and linux/vmalloc.h
which are not needed anymore since the removal of modules management.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/mm/kasan/kasan_init_32.c | 19 ++++---------------
1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index c41e700153da..c9d053078c37 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -5,9 +5,7 @@
#include <linux/kasan.h>
#include <linux/printk.h>
#include <linux/memblock.h>
-#include <linux/moduleloader.h>
#include <linux/sched/task.h>
-#include <linux/vmalloc.h>
#include <asm/pgalloc.h>
#include <asm/code-patching.h>
#include <mm/mmu_decl.h>
@@ -34,31 +32,22 @@ static int __init kasan_init_shadow_page_tables(unsigned long k_start, unsigned
{
pmd_t *pmd;
unsigned long k_cur, k_next;
- pte_t *new = NULL;

pmd = pmd_ptr_k(k_start);

for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) {
+ pte_t *new;
+
k_next = pgd_addr_end(k_cur, k_end);
if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)
continue;

- if (!new)
- new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);
+ new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);

if (!new)
return -ENOMEM;
kasan_populate_pte(new, PAGE_KERNEL);
-
- smp_wmb(); /* See comment in __pte_alloc */
-
- spin_lock(&init_mm.page_table_lock);
- /* Has another populated it ? */
- if (likely((void *)pmd_page_vaddr(*pmd) == kasan_early_shadow_pte)) {
- pmd_populate_kernel(&init_mm, pmd, new);
- new = NULL;
- }
- spin_unlock(&init_mm.page_table_lock);
+ pmd_populate_kernel(&init_mm, pmd, new);
}
return 0;
}
--
2.25.0
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