[PATCH] mm: uml pte atomicity
There's usually a good reason when a pte is examined without the lock; but it
makes me nervous when the pointer is dereferenced more than once.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/kernel/process_kern.c b/arch/um/kernel/process_kern.c
index 0d73cee..34b54a3 100644
--- a/arch/um/kernel/process_kern.c
+++ b/arch/um/kernel/process_kern.c
@@ -222,6 +222,7 @@
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
+ pte_t ptent;
if(task->mm == NULL)
return(ERR_PTR(-EINVAL));
@@ -238,12 +239,13 @@
return(ERR_PTR(-EINVAL));
pte = pte_offset_kernel(pmd, addr);
- if(!pte_present(*pte))
+ ptent = *pte;
+ if(!pte_present(ptent))
return(ERR_PTR(-EINVAL));
if(pte_out != NULL)
- *pte_out = *pte;
- return((void *) (pte_val(*pte) & PAGE_MASK) + (addr & ~PAGE_MASK));
+ *pte_out = ptent;
+ return((void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK));
}
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